BYGL Weekly News for October 29, 2018

BYGL Weekly News for October 29, 2018

 

 

The following articles were compiled during the last 7 days by members of the Extension, Nursery, Landscape, Turf (ENLT) team to benefit those who are managing a commercial nursery, garden center, or landscape business or someone who just wants to keep their yard looking good all summer.  Access the BYGL website for additional information on other seasonal topics at: http://bygl.osu.edu

 

For more pictures and information, click on the article titles.  To contact the authors, click on their names.

 

 

A Diagnostic Dilemma Reveals an Unusual Plant Disease

Authors Joe Boggs

Published on October 23, 2018

 

 

We strive to post BYGL Alerts based on timely, current observations.  However, sometimes our discoveries are made much later as we try to identify what we photographed during the growing season.  Such is the case with this report.

 

This past June, I came across some odd, wart-like symptoms on the upper leaf surfaces of plants I could only identify as some type of morning glory (family Convolvulaceae).  I was certain at the time that the symptoms were caused by an eriophyid mite (family Eriophyidae).  The “warts” looked like symptoms produced by oak leaf blister mites, Aceria triplacis, on its namesake host.  Or, walnut pouch galls produced by the eriophyid, Eriophyes brachytarsus.

 

Of course, the first question you should ask in plant problem diagnostics is “what is the plant?”  I was confident at the time that the plant was some type of morning glory, but I couldn’t find a diagnostic “fit” by searching the web using “eriophyid mites” and “morning glory” or variations on this theme.  So, I abandoned the search for another day; it was June and there were plenty of other diagnostic shiny things to pursue.

 

My lack of persistence came home to roost today as I was trying to label the images taken at the time so I could use them for teaching.  I had no diagnosis, or even a correct plant ID, to guide me on where to place the pictures in my image library and I hate adding more images to my ever-expanding “Unknowns” image folder.

 

I started all over again and finally identified the plants in my pictures:  wild sweet potato (Ipomoea pandurata, family Convolvulaceae).  This plant was new to me although I have probably walked past it many times.

 

Armed with a plant name, I began searching the web for information on eriophyid mites on wild sweet potato … and barreled down a diagnostic blind alley by ignoring another question you should ask in plant problem diagnostics:  “what exactly do you see?”  I consider this one of the most important questions to avoid getting lost in the diagnostic wilderness.

 

Looking closely at one of my images, I saw tiny, white, puffball-like structures in the indentations on the underside of the leaves rather than the expected felt-like material produced by an eriophyid mite.  It wasn’t an eriophyid mite after all; it was possibly a plant disease!  I was emerging from the diagnostic wilderness!

 

A quick search for diseases of wild sweet potato revealed a disease and plant pathogen that were new to me.  The disease is called white rust which may indicate a fungal infection is involved; however, the pathogen is Albugo ipomoea-panduratae.  This is not a fungus; it’s an oomycete.

 

These fascinating organisms were once lumped in with fungi.  However, oomycetes are now grouped in completely different taxonomic categories; some even say a different kingdom.  Unfortunately, many types are still given names that make them sound like fungi such as water molds or downy mildews.

 

Knowing that oomycetes are not fungi is more than a taxonomic exercise.  For one, oomycetes go through a mobile stage with whip-like flagella that allows them to swim in water.  This explains why irrigation ponds and streams can play an important role in spreading these organisms and their resulting plant diseases.

 

In fact, some water molds produce very significant plant diseases such as downy mildew of impatiens produced by Plasmopara obducens and downy mildew of cucurbits produced by Pseudoperonospora cubensis.  Of course, the most notorious of all is late blight of potato produced by Phytophthora infestans which was responsible for the Irish potato famine and resulting diaspora of the Irish people.

 

White rust can occur on both cultivated and wild sweet potatoes as well as many other morning glory family members.  However, various web resources indicate the disease rarely causes damage severe enough to warrant control measures.  Still, the location where I found the infected wild sweet potato plants may speak to the connection between water and pathogen spread.  The plants are in a park frequently inundated by flood waters from the Little Miami River.

 

I’ve learned from experience that a successful plant problem diagnosis is often the result of perseverance; even dogged persistence.  Sometimes it happens quickly, sometimes it takes months or even years.

 

I also keep re-learning that ignoring important plant problem diagnostic questions can add to that time; even contribute to my “unknowns” folder.  We’re updating our “20 Questions on Plant Diagnosis” OSU Fact Sheet.  In the meantime, you can review the current version under “More Information” below.  Obviously, I need to take my own advice.

 

More Information

20 Questions on Plant Diagnosis

https://ohioline.osu.edu/factsheet/plpath-gen-3

 

 

 

 

 

 

Thursday, February 7, 2019

Sharonville Convention Center

11355 Chester Rd

Cincinnati, OH  45246

 

SAVE THE DATE:  MARK YOUR CALENDARS!

ONLINE REGISTRATIONComing Soon!

Don’t miss out on:

è Cutting edge horticultural training sessions

è Networking opportunities

è Vendor/Trade Show

è Pesticide Re-certification (Ohio, Indiana, Kentucky) & Professional credit opportunities

è Keynote:  “The State of Trees,” Dr. Dan Herms, Vice President of Research & Development, The Davey Tree Expert Company

Sponsorship Opportunities are Available!

Your business can reach “the best of” the Tri-state’s green industry:  three straight years of record-breaking attendance! 

 

Click this hotlink to learn more:   https://hamilton.osu.edu/program-areas/agriculture-and-natural-resources/horticulture/2019-tri-state-green-industry        

 

The Tri-State Green Industry Conference is a collaborative educational effort between:

Ohio State University Extension

University of Kentucky Cooperative Extension

Purdue Extension

Cincinnati State Technical and Community College

Boone County Arboretum

Cincinnati Zoo and Botanical Garden

Spring Grove Cemetery and Arboretum.

Questions? Call Julie Crook (513) 946-8998, or e-mail at: crook.46@osu.edu

BYGL Weekly News for October 15, 2018

BYGL Weekly News for October 15, 2018

The following articles were compiled during the last 7 days by members of the Extension, Nursery, Landscape, Turf (ENLT) team to benefit those who are managing a commercial nursery, garden center, or landscape business or someone who just wants to keep their yard looking good all summer.  Access the BYGL website for additional information on other seasonal topics at: http://bygl.osu.edu

 

For more pictures and information, click on the article titles.  To contact the authors, click on their names.

 

 

Get Ready for a Little Breaking and Entering

Authors Joe Boggs

Published on October 11, 2018

 

 

Our drop in temperatures throughout Ohio will no doubt convince fall home invading insects that it’s time to seek winter quarters.  These unwelcomed guests typically include Boxelder Bugs (Boisea trivittatus); Western Conifer Seed Bugs (Leptoglossus occidentalis); Magnolia Seed Bugs (Leptoglossus fulvicornis); Multicolored Asian Lady Beetles (Harmonia axyridis); and the most notorious of all, Brown Marmorated Stink Bugs (Halyomorpha halys).

 

These home invaders have several things in common.  First, their populations may vary considerably even across relatively short distances.  Some homes may be inundated while those located just a few miles away remain free of insect marauders.

 

Even more challenging, late-season outdoor populations are not always a reliable predictor of indoor excursions.  Just because you didn’t see them in September doesn’t mean you won’t see them sitting next to you on your sofa in November.

 

A Series of Unfortunate Events

The second thing these home invaders have in common is their “cold-blooded” physiology meaning the speed of their metabolism is mostly governed by ambient temperature; the higher the temperature, the faster their metabolism, and the faster they “burn” fat.  Yes, insects have fat, but it’s confined by their hard exoskeletons so they don’t suffer ever-expanding waistlines.

 

These insects feed voraciously in late summer to accumulate fat.  They then seek sheltered locations in the fall where cool temperatures slow their metabolism during the winter so they will not exhaust their stored fat reserves.  This survival strategy keeps them alive since there is nothing for them to eat throughout the winter.

 

The insects are attracted to the solar heat radiating from southern or western facing roofs and outside walls as well as the warmth radiating from within.  This can lead them into attics, outside wall voids, and spaces around door jams and window frames that make perfect overwintering sites.  They stand a good chance of surviving the winter as long as they remain in these cool, protected sites.

 

However, sometimes they make a terrible error; for both the insect and a homeowner.  Instead of staying put, they continue to follow the heat gradient into homes.  This is accidental and disastrous for the insects because the high indoor temperatures cause them to burn through their fat reserves and starve to death.  And, they do not go gentle into that good night!  Starving brown marmorated stink bugs and multicolored Asian lady beetles commonly take flight to buzz-bomb astonished homeowners and terrified pets.

 

The Best Defense is a Good Offense

The best defense against home invaders buzzing or lumbering around inside a home is to prevent them from entering in the first place.  Although there are effective indoor marmorated stink bug traps, they shouldn’t be used in place of sealing openings that allow the bugs to enter the home.  An ounce of prevention is worth a pound of bugs.

 

Large openings created by the loss of old caulking around window frames or door jams provide easy access into homes.  Such openings should be sealed using a good quality flexible caulk or insulating foam sealant for large openings.

 

Poorly attached home siding and rips in window screens also provide an open invitation.  The same is true of worn-out exterior door sweeps including doors leading into attached garages; they may as well have an “enter here” sign hanging on them.  Venture into the attic to look for unprotected vents, such as bathroom and kitchen vents, or unscreened attic vents.  While in the attic, look for openings around soffits.  Both lady beetles and stink bugs commonly crawl upwards when they land on outside walls; gaps created by loose-fitting soffits are gateways into home attics.

 

Handle with Care

Insects that find their way into a home should be dealt with carefully. Swatting or otherwise smashing these insects can cause more damage than leaving them alone since fluids inside their bodies can leave permanent stains on furniture, carpets, and walls.  Also, mashing multicolored Asian lady beetles and brown marmorated stink bugs can release a lingering eau de bug; lady beetles have stinky blood and stink bugs are called stink bugs for a reason!

 

Vacuum cleaners present their own set of risks.  A “direct-fan” type of vacuum cleaner should never be used.  Passing the refuse through an impeller will create a horrifying bug-blender!  Even a “fan-bypass” type (e.g. Shop-Vac) with the refuse bypassing the impeller can develop a distinctive scent if used on stink bugs because the bugs will release their defense odor in response to swirling around inside the vacuum tank.

 

However, fragrant misadventures with vacuum cleaners can be minimized with a slight modification involving using a nylon ankle sock.  The method is clearly described in the OSU Factsheet titled, Multicolored Asian Lady Beetle (see “More Information” below).

 

Small numbers of home invaders can be scooped-up and discarded by constructing a simple but effective “bug collector” using a plastic pint water bottle.  Large numbers of insects can be quickly dispatched by placing a small amount of soapy water in the bottom of the bug collector.

 

More Information

OSU Factsheet, Multicolored Asian Lady Beetle, ENT-44

https://ohioline.osu.edu/factsheet/ENT-44

 

 

 

 

Calico Scale Crawlers Move to Stems

Authors Joe Boggs

Published on October 11, 2018

 

 

Infestations of the non-native Calico Scale (Eulecanium cerasorum) can be difficult to detect during the growing season.  However, clusters of crawlers on blackened stems coupled with dead females are key diagnostic features for spotting calico scale at this time of the year.

 

Calico scale is a “soft scale” meaning that female scales are protected by a soft helmet-shaped shell.  This is a relatively large soft scale with mature female shells measuring about 1/4″ in diameter. The scale’s common name comes from the starkly contrasting calico pattern of black-and-white markings on the shells of live females found on the stems in the spring.

 

Females produce fertile eggs in late-spring to early-summer without the need for mating; there are no males.  This form of reproduction without males is called parthenogenesis.

 

The females then die and turn orangish-brown, but they don’t disappear.  The dead females may give the false impression that control efforts such as an insecticide application were effective.  In fact, I’ve have received pictures in the past of calico scale females that died of natural causes being used as proof that an insecticide application was effective.

 

Some of the dead females will remain attached to the stems well into the fall.  However, others may become detached leaving behind a distinct silvery-white deposit that starkly contrasts with black sooty molds.  Indeed, if you know what to look for, you can easily spot these deposits on stems 10 – 15′ above the ground.

 

The 1st instar crawlers that hatch from the eggs distribute themselves among their host’s leaves where they crowd together along leaf veins and tap into phloem vessels.  They remain on the leaves throughout the growing season molting into 2nd instar crawlers in mid-summer.  They migrate back to stems prior to the leaves dropping in autumn and settle down for the winter.  It’s a smart move; they would have a terrible experience if they remained on the shed leaves.

 

The overwintered crawlers molt into parthenogenetic females in the spring.  There is one generation per season.

 

As with all soft scales, calico scale adults and crawlers feed by inserting their piercing-sucking mouthparts into phloem vessels to extract amino acids that are dissolved in the sugary plant sap.  Both adults and crawlers discharge excess sap from their anus in the form of sticky, sugary “honeydew” that drips onto the leaves, stems, and branches of scale-infested trees.

 

Black sooty molds colonize the honeydew to produce blackened twigs, branches and trucks which is one of the most obvious symptoms of a heavy calico scale infestation.  The blackening becomes particularly evident after trees shed their leaves allowing sunshine to spotlight the black fungal growth.

 

Calico scale can infest a wide variety of deciduous trees including buckeye, crabapple, dogwood, elm, hackberry, hawthorn, honeylocust, horse-chestnut, magnolia, maple, oak, pear, redbud, sweetgum, tuliptree, yellowwood, witchhazel, and zelkova.  However, I’ve found they are particularly fond of honeylocust; it’s my “go-to” tree for looking for calico scale in an urban landscape.

 

There are no effective management tactics that can be applied at this time of the year to suppress a calico scale infestation.  However, discovering a calico scale infestation now will give you time to plan a management strategy for next season.

 

As with most soft scales, calico scale is seldom a direct killer of established landscape trees.  But heavily infested trees may suffer branch dieback and the accumulated stress caused by substantial sap loss coupled with other stress-producing conditions may kill trees.  So, the best first step in scale management is to resolve other issues that may affect tree health.

 

 

 

Fall Color: It’s not just for leaves anymore!

Authors Thomas deHaas

Published on October 11, 2018

 

 

As we approach fall and its wide range of colors, we sometimes forget about other sources of color in the landscape: FRUIT!

Viburnums, Deciduous Hollies, even Dogwoods can provide fall color in the landscape.  Viburnum fruit can range from almost black to purple (Viburnum dentatum)

to red, (Viburnum trilobum ‘Wentworth’) even pink (Viburnum nudum) and yellow (Viburnum dilitatum ‘Michael Dodge).

 

In addition, these fruits can attract wildlife to the landscape. Deciduous Holly berries, often known as winterberries can range from bright red (Ilex verticillata ‘Stoplight’) to orange and yellow (Ilex verticilatta ‘Winter Gold’).  The fruit will remain after the leaves fall and until eaten by birds and wildlife.  Beautyberry can provide a splash of violet-purple color (Callicarpa dichotoma ‘Issai’).

 

Even flowering dogwood can put on a show with its red fruit.(Cornus florida)

 

So as you plan for next year and what plants to consider, don’t think just about flowers or fall color. Consider the fruit.

 

 

 

Great Lakes Apple Crunch Day – October 11, 2018

Authors Amy Stone

Published on October 10, 2018

 

 

Thursday, October 11, 2018 is Great Lakes Apple Crunch Day. The purpose of the day is to celebrate National Farm to School Month by crunching into locally and regionally grown apples. Everyone, regardless of your age, is welcome to Crunch!

 

Here are some details from Wisconsin who coordinates this multi-state event.

  • Location:Any site including K-12 schools, early care settings, hospitals, colleges/universities, business campuses, state agencies and other organizations across Minnesota, Wisconsin, Illinois, Indiana, Michigan and Ohio
  • Details:Celebrate National Farm to School Month by crunching into apples at NOON on Thursday, October 11. Everyone is welcome to Crunch! Although we aim for a collective Crunch on October 11, you are welcome to Crunch any day or time in October that works for you.
  • Join in!Last October 1,543,781 students, children, teachers, and good food supporters across the region crunched. Let’s join forces and meet the ONE MILLION CRUNCH goal again this year! Visit the Great Lakes Apple Crunch Facebook page to get updates and see photos from last year’s Crunch. You can find the page at:  https://www.facebook.com/GreatLakesGreatAppleCrunch

 

In Ohio you can actually register a group by logging in at: https://uwmadison.co1.qualtrics.com/jfe/form/SV_e5tFJJ58wr0g3at

 

In addition another web-resource that is being promoted this fall is: https://ohioapples.com/  This website will connect you with local orchards. You are able to search by GPS, by county, by orchard or by keyword. There is also information about apple nutrition, recipes and information on handling and storing Ohio apples.

 

So whether you take a crunch tomorrow as part of a larger event, be sure to enjoy some local apples before the season disappears.

 

Earlier this month, I was part of a behind-the-scenes tour at a local orchard in Northwest Ohio. As part of the tour we did an apple tasting of a dozen varieties – both antique varieties and those that are newer. The owner shared with the group about their involvement in the Midwest Apple Improvement Association. To learn more about this group of growers, check out their website at: http://www.midwestapple.com/index.php

 

Happy National Apple Crunch Day – one day early!

 

More Information

Great Lakes Apple Crunch Day

https://www.cias.wisc.edu/applecrunch/

 

 

 

 

Why Trees Matter – October 24, 2018

Authors Amy Stone

Published on October 10, 2018

 

 

Join us October 24, 2018 for the annual ‘Why Trees Matter Forum’ at the Miller Pavilion at Secrest Arboretum, Wooster, Ohio. We love trees – do you?

 

This year we welcome keynote speaker Dr. Barb Fair from North Carolina State University. There is a host of other speakers to round out the day where we get to focus on all the reasons trees matter.

 

You won’t want to miss out on this educational program all about trees! See you at Secrest on October 24!

 

More Information

Link to Registration

https://woodlandstewards.osu.edu/events/why-trees-matter-forum

 

 

 

 

A Spicy Surprise

Authors Joe Boggs

Published on October 9, 2018

 

 

I received a container of ground cayenne peppers with a surprise far greater than the capsaicin kick.  The product was heavily infested with cigarette beetles (Lasioderma serricorne, family Anobiidae).  The homeowner noted they hadn’t used the product for some time.  However, they had noticed small brown beetles buzzing around their home and collecting on their window seals.

 

Cigarette beetles and drugstore beetles (Stegobium paniceum, family Anobiidae) are two common “pantry pests” in Ohio.  Both beetles are reddish-brown and may feed on the same products.  However, cigarette beetles are more rounded in their shape and covered in long hairs giving them a somewhat fuzzy appearance (see “More Information” below).

 

Cigarette beetles are so-named because they were commonly found feeding on tobacco products.  The beetles may also be found feeding and fouling a wide range of dried and processed products including paprika, chili powder, dried ginger, dates, raisins, dried pasta, pet foods, stored grains, cereals, and seeds of all sorts including birdseed and seeds found in dried flower arrangements.

 

Although their primary means of transport and spread is through infested materials, cigarette beetles also live outdoors and may find their way into homes.  For this reason, purchased products cannot always be blamed with certainty as being the source of a home pantry invasion.  Still, it’s a good idea for products to be used before their “sell by” date and products being held in reserve to survive a zombie apocalypse should be periodically inspected.

 

Outdoors, the beetles are good flyers and most active at dusk.  They are attracted to light and I have found them buzzing around porch lights at night.  They reverse course inside homes with the beetles flying from darkened interiors to windows.  Homeowners may find a collection of dead beetle bodies on window seals which is a strong indication of a cigarette beetle infestation.

 

Finding cigarette beetles or any other pantry pest in a home should trigger an immediate search and destroy mission.  All possible food sources throughout the home (e.g. basements, attached garages) should be opened and inspected.  These beetles can spread rapidly throughout a home to produce many “satellite infestations.”

 

Infested products will include beetles; fuzzy, white, grub-like beetle larvae; and hardened pupal cells from which the adults emerge.  Of course, cigarette beetles change both the appearance and consistency of their food as they pass it through their gut.  Whether the product is a fine powder like ground cayenne peppers or large clumps like pet food or breakfast cereal, it will all get converted into sawdust-like frass (= excrement) in the end.

 

Infested products should be double-bagged and placed outside to await trash collection.  The products should not be stored in a garage any structure attached to a home.  Products that are not infested should be placed in sealed plastic containers.  Plastic food storage bags should not be used because the beetles can chew through the thin plastic.

 

Traps are available that are baited with the female sex pheromone for the cigarette beetle, serricornin (4, 6-dimethyl-7-hydroxy-nonan-3-one).  The traps only attract males and are best used for monitoring to make certain a satellite infestation isn’t missed.  The traps aren’t effective enough in a home environment to eliminate an infestation.

 

On a final note, we discussed this infestation during our BYGL Zoom Inservice this morning and Pam Bennett (OSU Extension, Clark County) noted that finding cigarette beetles in the ground cayenne peppers should give pause to the idea that capsaicin (the “hot” in hot peppers) is a good insecticide.  Indeed, the infestation provided clear evidence that some insects, like cigarette beetles, can revel in it!

 

More Information

Cigarette Beetle

http://entnemdept.ufl.edu/creatures/urban/stored/cigarette_beetle.htm

 

 

 

 

Time to Clean-Up Garden Peonies

Authors Joe Boggs

Published on October 8, 2018

 

 

Peony leaf blotch disease is caused by the fungus Graphiopsis chlorocephala (formerly Cladosporium paeoniae).  The fungus produces diseases with different names depending on the symptoms.

 

Leaf blotch occurs when infections produce large, shiny, brown or purple leaf lesions.  Peony “red spot” and “measles” occur when fungal infections produce distinct red to reddish-black spots on the stems.  Typically, the measles symptoms appear before the leaf blotch symptoms with the stem lesions expanding as the season progresses.

 

Peonies are also susceptible to a specific gray mold fungus, Botrytis paeoniae.  The fungus may infect newly emerging shoots in the spring covering them in a fine, velvety gray mold.  The Botrytis can also infect flower parts later in the season to produce “bud blast” with flower buds failing to open and “flower blight” with opened flowers collapsing and becoming blackened.  Fungal infections can also move down the stems to produce a “shoot blight.”

 

Unfortunately, web searches may yield reports with images that clearly show peony leaf blotch but are mislabeled “Botrytis blight,” or images of Botrytis infections that are blamed on the leaf blotch fungus.  These fungi have very different disease cycles.  Of course, it’s not unusual to find both diseases on the same peony plant.

 

The good news is that these diseases are not considered to be killers of garden (herbaceous) peonies.  Symptoms tend to escalate as the season progresses meaning plants apparently have enough time to produce and store enough carbohydrate to support regrowth the following season.  However, both of these diseases can seriously detract from the aesthetic value of peonies in landscapes meaning there is value in trying to halt infections and subsequent symptoms.

 

Management

 

The Disease Triangle illustrates the three conditions that must be met for a plant disease to develop:  the pathogen must be present; the plant host must be susceptible to infection; and environmental conditions must be present that support infection and disease development.  Removing only one of these conditions will prevent disease development.

 

Various web reports on peony leaf blotch recommend planting less susceptible varieties; however, I have found no scientific publications presenting data from plant trials that assessed disease susceptibility.  There are anecdotal accounts that susceptibility varies among the different peony varieties and I’ve observed this in peony plantings.  Of course, other factors may be responsible for varying levels of infections such as micro-environments acting to increase or decrease infections within the plantings.

 

Some disease suppression may be achieved by environmental management such as avoiding overhead irrigation.  However, it’s difficult to manage natural overhead irrigation in the form of rainfall.

 

Suppression of the pathogen by fungicidal applications can be effective; however, success is generally problematic.  Multiple applications are required over a significant portion of the growing season and heavy rainfall events can mean a shortening of the intervals between applications.  Relying on fungicides alone is not likely to be successful for home gardeners and can even present a serious challenge for landscape management professionals.

 

Removal of the plant pathogens through sanitation is one of the effective management strategies for both of these garden peony diseases.  This approach focuses on getting rid of infectious tissues that harbor the fungi throughout the growing season or over the winter.

 

Here are the ABCs of managing these diseases using all parts of the Disease Triangle starting this fall:

 

Fall (right now!):

  1. Cut, remove and destroy all of the top growth down to the soil line.
  2. Rake, remove and destroy all mulch and plant debris that was beneath the infected plants.
  3. Redistribute new mulch for the winter to a depth of no more than 2 – 3″.  This will suppress the release of fungal spores next spring from infectious debris that may have been missed during the fall clean-up.

 

Spring:

Protect new shoots using an appropriately labeled fungicide.  The product label must include the site (e.g. landscape, nursery, etc.) and make certain peonies are not listed as being sensitive to the product.  This is an added protective measure and requires just one or two applications.  I have heard a number of anecdotal accounts of peony leaf blotch being successfully managed without these fungicidal applications in the spring.  However, these applications should be considered if there were heavy Botrytis infections this season.

 

During the Growing Season:

  1. Remove and destroy bloom buds, flowers, and stems showing signs of Botrytisinfections.  “Dead-heading” spent flowers is also recommended.
  2. Selectively prune plants to improve air circulation which will enhance leaf and stem drying.
  3. Avoid overhead irrigation; use drip irrigation if available.

 

 

 

 

OHIO STATE UNIVERSITY EXTENSION

Where trade names are used, no discrimination is intended and no endorsement by Ohio State University Extension is implied. Although every attempt is made to produce information that is complete, timely, and accurate, the pesticide user bears responsibility of consulting the pesticide label and adhering to those directions.

Ohio State University Extension embraces human diversity and is committed to ensuring that all research and related educational programs are available to clientele on a nondiscriminatory basis without regard to race, color, religion, sex, age, national origin, sexual orientation, gender identity or expression, disability, or veteran status. This statement is in accordance with United States Civil Rights Laws and the USDA.

CFAES provides research and related educational programs to clientele on a nondiscriminatory basis. For more information: [ http://go.osu.edu/cfaesdiversity ].

Any materials in this newsletter may be reproduced for educational purposes providing the source is credited.

 

 

BYGL Weekly News for October 8, 2018

BYGL Weekly News for October 8, 2018

The following articles were compiled during the last 7 days by members of the Extension, Nursery, Landscape, Turf (ENLT) team to benefit those who are managing a commercial nursery, garden center, or landscape business or someone who just wants to keep their yard looking good all summer.  Access the BYGL website for additional information on other seasonal topics at: http://bygl.osu.edu

For more pictures and information, click on the article titles.  To contact the authors, click on their names.

 

A Most Unusual Grub

Authors Joe Boggs

Published on October 6, 2018

 

 

I came across a green June beetle (Cotinis nitida, family Scarabaeidae) larva (grub) last Thursday slowly slinking across a driveway.  This is one of the largest and strangest white grubs you’ll ever see in Ohio.  First, the mature grubs are huge measuring well over 1″ in length.  They look like white grubs on steroids.

 

Second, the grubs practice a highly unusual mode of movement:  they crawl along on their backs in an undulating motion!  You can see this bizarre upside-down grub-crawl in a video I posted by clicking on “Grub Crawl” under “More Information” below.

 

The grubs rolling motion cause them to superficially resemble caterpillars.  In fact, when I first saw this grub creeping along, I thought it was a caterpillar.  Since green June beetles crawl without the aid of their legs, you’ll notice their legs are smaller than those of other white grubs, particularly in relation to the size of their bodies.

 

The other unusual thing about these grubs is that unlike other white grubs affecting turfgrass, green June beetle grubs create vertical burrows 10-12″ into the soil, and they normally remain closely associated with these burrows.  They primarily feed on decaying organic matter such as thatch and much of their damage to turfgrass is associated with their burrowing and tunneling behavior.  However, they have been known to feed on turfgrass producing damage in irregular patches.

 

The grubs venture out of their burrows in late-evening or during the night to feed or to go on an upside-down crawl-about in search of more food.  They may also be driven out by heavy rains to appear in large numbers meandering across driveways and sidewalks or dropping into swimming pools.  Although they can damage turfgrass, they’re primarily considered a nuisance pest.

 

The same is true of the large, metallic green adult beetles.  Although they may occasionally feed on tree leaves as skeletonizers, or they may be found on ripening fruit, the beetles are most notorious for emerging en masse to terrorize backyard gardeners, golfers, sunbathers, small pets, etc., as they cruise about 2 – 3 ft. above the ground.  Their large size coupled with an audible “buzzing” sound and low-level flight plan may induce mild panic in individuals unfamiliar with this insect.  Like their grubs, the beetles have great entertainment value.

 

There appears to be a strong association between high organic and high populations of this beetle.  So, control efforts should focus on reducing organic matter, particularly thatch, beneath infested lawns.  For example, thatch reduction using core aeration to hasten decay by infusing oxygen into the organic matter may eventually make infested lawns less attractive as grub development sites by these buzz-bombing beetles.

 

The grubs are also food for the larvae of the blue-winged wasp (Scolia dubia).  This wasp is a common visitor to late-season blooms such as those produced by goldenrod (Solidago spp.).  Providing a good late-season nectar source, such as planting late-bloomers in landscapes, can help draw in this parasitoid wasp.

 

On a final note, I posted a BYGL Alert about this wasp just a few weeks ago (see Blue-Winged Wasps Cruising Lawns, September 17, 2018) and incorrectly stated that it is “a parasitoid of white grubs with a particular affinity for green June beetle (Continus nitida) and Japanese beetle (Popillia japonica) grubs.”  This is only half-right.  As turfgrass entomologist and (thankfully!) BYGL fact-checker, Dan Potter (Entomology, University of Kentucky) pointed out, there is no scientific evidence this wasp attacks Japanese beetle grubs.  However, it’s well established that the wasp is the nemesis of green June beetle grubs.

 

More Information

Grub Crawl

https://youtu.be/EF8UeznxE5M

 

 

 

Bullet Galls and Their Guards

Authors Joe Boggs

Published on October 6, 2018

 

 

Oak bullet galls have reached their maximum size for the season and will soon release their developing female wasps.  The galls arise from twigs and are produced under the direction of several species of cynipid wasps (family Cynipidae) belonging to the genus Disholcaspis.  So, you may find different types of bullet galls depending on the exact gall-making wasp species that directed their creation.

 

Most bullet galls are more or less round-shaped and measure about 1/2″ in diameter.  Colors vary from light green to reddish-green, to light brown depending on the wasp species and the age of the gall.  Some bullet galls are covered in very fine, short hairs, while others are completely smooth.  They cause no appreciable harm to their oak hosts because they do not disrupt the vascular flow in the twigs.

 

Complex Life Cycle

 

The life cycle of bullet gall-wasps involves two different types of galls produced at different times of the year.  The current bullet galls will give rise to female wasps around the end of this month; no males are produced.  Wasp emergence is heralded by a small hole in the gall.  Once the wasps have emerged, the “spent” galls shrivel, darken in color, and some will detach from the oak stems over the winter.

 

The self-fertile females crawl to a dormant leaf bud where they lay a single egg per bud.  These eggs along with the resulting wasp larvae stimulate the tree to produce small, inconspicuous leaf galls in the spring.  Both male and female wasps develop inside these leaf galls and adults emerge in mid-to-late spring.

 

The mated females fly or crawl to newly elongated twigs where they insert their eggs through the phloem to be in contact with the cambium.  Or, depending on the gall-wasp species, they insert an egg in a new leaf bud.  This is important because the wasp requires the services of undifferentiated (meristematic) cells to grow their bullet galls.

 

As with all galls produced by wasps, midge flies, and other insects, the bullet wasp gall-maker uses various chemicals to turn plant genes on and off at just the right time to induce and direct gall formation.  Thus far, no researcher has ever duplicated this interaction without the aid of an insect gall-maker.

 

Paying for Protection

 

Many bullet galls include extrafloral nectaries (a plant organ) in their gall structure.  I find this to be incredible, but it’s not unique to bullet galls.  A number of other cynipid wasp galls also exude nectar including the oak bud gall produced by the wasp Neuroterus vesicula.

 

The nectar exuded from the galls attract a variety of stinging insects including bald-faced hornets (Dolichovespula maculata) and yellowjackets (Vespula spp.) as well as biting insects such as carpenter ants (Camponotus spp.).

 

Yellowjackets and bald-faced hornets are Jekyll and Hyde wasps.  During much of the season, they chow-down on soft-bodied insects such as caterpillars and sawfly larvae.  Their predatory lifestyle makes them beneficial insects.  However, in the fall, they switch from high-protein diets to high carbohydrate diets.  They can be a serious stinging-nuisance as they compete with our own high-carb consumption of soda, donuts, and certain adult beverages.

 

Bullet gall-makers take advantage of the wasp’s high-carb hankering with the nectar oozing from the extrafloral nectaries on the galls serving as “wasp candy.”  Of course, ants will also show-up to the sugar party.

 

Presumably, the close attention of stinging and biting insects prevents the immature gall-making wasp larvae located within the galls from receiving the unwanted attention of predators and parasitoids.  In other words, a little sugar bribe makes the gall-home safe for the gall-makers helpless offspring.

 

 

 

Small but Mighty Fly

Authors Joe Boggs

Published on October 5, 2018

 

 

I came across a beautiful little native fly this week while taking pictures of pollinators on common goldenrod (Solidago canadensis).  The fly, Trichopoda pennipes, doesn’t have a common name, but some web-based resources refer to it as the “feather-legged fly.”  This is not entirely correct.

 

It is just one type of feather-legged fly with the common name given to all members of the Trichopoda genus.  The name of the genus comes from the Greek tricho meaning “hair;” and poda meaning foot.  In fact, some refer to these flies as “hairy-legged flies.”  Even with the naked eye, you can clearly see the hair-like structures on the hind tibia that are responsible for the common and scientific names.

 

I came across an online resource that referred to Trichopoda pennipes as the orange-and-black feather-legged fly.  Although this common name hasn’t been approved by the Entomological Society of America, I like it because it’s so descriptive. So, I’ll refer to it in short-hand as the O&B fly.

 

Other fascinating features that are clearly visible on the O&B fly are their two wings which mean it’s truly a fly belonging to the order Diptera:  Di = two; ptera = wings.  Flies actually have four wings but the hind wings are modified into two knob-like structures called halteres which are used by flies for balance during flight.  It’s one reason flies are such good flyers and are called flies.  The saddlebag-shaped halteres on the O&B fly are relatively large compared to many dipterans and they are covered in orange scales making them easy to see.

 

The O&B fly belongs to the fly family Tachinidae (the parasitoid flies) and is found throughout much of North America.  Members of this family are well known for their prowess in tracking their hosts and for their larvae (maggots) ravaging their hosts from the inside out.

 

The O&B fly focuses its parasitoid scrutiny on the “true bugs” (order Hemiptera, suborder Heteroptera).  They can pay particular attention to some significant stink bugs (family Pentatomidae) including the southern green stink bug (Nezara viridula) notable for damaging cotton and other field crops and the brown marmorated stink bug (Halyomorpha halys) notable for damaging a number of different crops then invading homes to brag about it.  The fly will also parasitize various leaf-footed bugs (family Coreidae) such as the squash bug (Anasa tristis).

 

Research has shown that sex pheromones used by the southern green stink bug females to attract mates can be detected and used by the O&B fly to zero in on the bugs.  This devious host detection method is not unique to this fly; it’s been reported with other tachinid flies.

 

Once a bug host is located, the O&B fly females lay single or multiple eggs on the surface of their host.  The resulting fly maggots bore into their host; however, only one maggot survives to consume the entire contents of their bug host.  Again, this is not unique to this fly, or even to flies.  There are some parasitoid wasps that also subject their offspring to a survival of the fittest test.

 

Some parasitism rates by the O&B fly that are reported outside of scientific publications sound too good to be true, so they probably are.  However, various research papers do indicate this fly can have some significant impacts under certain conditions.

 

For example, there appears to be a connection between nectar sources, successful adult mating, and higher rates of parasitism.  Yet another example of the value of providing food for a pollinator adult (e.g. butterfly gardens) so their parasitoid or predator offspring can help reduce the number of nearby plant pests.  Where have you heard that before?

 

 

 

ArborEatYumm: OSU’s College of Food…

Authors Jim Chatfield

Published on October 4, 2018

 

 

…FOOD Agricultural and Environmental Sciences. Let it never be forgot, the centrality of FOOD. Even in the landscape. So, Come one, come all.  Next Tuesday, October 9, at OSU’s Secrest Arboretum, from 5:00 – 8:00 pm, there will be a free Arbor-Eat-Um program. Edible landscaping. Bring your favorite landscape plant products that are edible: blueberry buckle, black chokeberry jam.

 

Mark Hoenigman and his pawpaw trifle, Cathy Herms and her Autumn olive pate de fruits – controlling invasives one bite at a time. Lois Rose and her Medlar jam. Ramp soup. Honey. Maple syrup. Dolgo crabapple butter – Mike Lee where are you?

 

Nothing from your landscape?  Just bring your appetite. Miller Pavilion. You do not need to register. Be there.

 

 

 

What Lies Beneath

Authors Joe Boggs

Published on October 3, 2018

 

 

I enjoy making unexpected discoveries with one revelation leading to the next and then the next like pulling apart one of those Russian nesting dolls.  My chain of discoveries started with finding “fresh” puffball mushrooms during a walk in a local park.  I was thrilled because I had never taken pictures of the early stages of these peculiar looking mushrooms.

 

Puffballs are the common name for the fruiting structures of a group of fungi that were once lumped together in the descriptively named but now obsolete taxonomic class, Gasteromycetes (Greek:  gaster = stomach; mycetes = fungus).  Unlike the mushrooms that we may love on our pizzas with the spores produced and released from external gill-like structures beneath a cap, the spores in puffballs are produced internally inside a hollow cavity called a gasterothecium (= stomach-like).

 

The puffballs I came across with their white, spongy interiors will eventually undergo a dramatic change to become brown sacs full of powdery spores that puff when squeezed; thus puffballs.  I hope to return to capture the next phase in their development unless someone steps on them to release clouds of spores.  Puffballs have great entertainment value.

 

I pulled up one of the puffballs and discovered the bottom was riddled with pits and holes created by pillbugs as they dined on the fungal delicacy.  I was thrilled because I had no pictures of these odd looking terrestrial crustaceans (phylum Arthropoda, subphylum Crustacea).  It was like lifting off the top of a Russian nesting doll to discover another doll hiding beneath.

 

Pillbugs are so-named because they roll themselves into a pill-like ball when disturbed.  This odd behavior gives rise to other common names such as armadillo bugs based on their roll-up behavior coupled with their obvious body plates.

 

You see this common name reflected by name of the pillbug family, Armadillidiidae.  It also appears in the name of the genus of the two most common pillbug species found in Ohio, Armadillidium vulgare (common pillbug) and A. nasatum.  Both are European natives that were introduced to North America so long ago it’s now common to think of them as native species.

 

Pillbugs live in dark, moist environments and are generally considered to be detritivores feeding on decaying plant debris.  However, on rare occasions, they may feed on living plant material and have been known to cause damage to vegetables including root crops like radishes and carrots as well as lettuce leaves and ripe tomatoes.  They may also become serious greenhouse pests by consuming seedling roots and young stems in contact with the soilless media.  However, pillbugs are mostly just nuisance pests because of their propensity to show up in large numbers where they’re least appreciated such as in cool, wet garages and basements.

 

Sowbugs (family Oniscidae) are not the same as pillbugs although they both may be found living in the same locations.  Sowbugs have two, small, pointed tail-like appendages that stick out of their back ends.  Pillbugs do not.  However, the big difference is that sowbugs cannot roll their bodies into round balls.  They may huff and puff and curl a bit, but they just can’t pull off the rolly-pollie body tuck.

 

Pillbug management around homes should focus on prevention through closing entry points and environment modifications to promote drying.  Door sweeps and door jambs should be inspected and action taken to close gaps that have become too wide.  Pillbugs benefit from high moisture, so running dehumidifiers will help keep basements and garages dry.  Mulch should be raked away from foundations to produce a “dry barrier.”  Also, decaying vegetation should be removed.

 

Of course, there are things that eat pillbugs which brings me to my third Russian doll discovery.  While taking pictures of the pillbugs crawling in and out of the cavities in the puffball, I came across a voracious predacious soldier beetle larva (Chauliognathus spp., family Cantharidae).  The soldier beetle larva was thrusting itself into the cavities to enjoy a pillbug meat treat.

 

Adult soldier beetles are also called “leatherwings” for their soft, flexible front wings.  The adults feed on nectar and pollen and are considered important plant pollinators.  In fact, goldenrod soldier beetles (C.  pennsylvanicus) are currently swarming over the flowers of its namesake native host plant.  Another common Ohio species, the margined leatherwing (C. marginatus), made its appearance this past spring and early summer on other flowering plants.

 

Soldier beetles and their predacious larvae are a good example of the value of providing food for a pollinator adult (e.g. butterfly gardens) so their predaceous larvae can help reduce pestiferous arthropods.  Research has shown the same is true for pollinators with parasitoid larvae.  It’s like opening a Russian nesting doll to discover unexpected treasure hidden beneath.

 

 

 

Diagnostics of Beech Leaf Disease: The Ultimate Beech Read

Authors Jim Chatfield  Joe Boggs

Published on October 2, 2018

 

 

Our knowledge of Beech Leaf Disease (BLD), an emergent problem on American beech (Fagus grandifolia) in northeast Ohio and nearby areas is still in the early stages. For example, we do not know what causes BLD.  The most promising development in learning causation is that we now have scientists with some grant funding on the case. Carrie Ewing in Enrico Bonello’s lab at Ohio State University is doing her PhD work on BLD.

 

We also have excellent monitoring and mapping of the disease, including Lake Metro Parks and BLD discoverer John Pojacnik and Cleveland Metro Parks, as well as the Ohio Department of Natural Resources Division of Forestry and Holden Arboretum.  But we do not know what causes BLD, if it is a pathogen whether it has a vector, the long-term threat to forest and landscape beeches, and on and on.

 

We do have some diagnostic aids: what BLD looks like as well as other problems that are often misdiagnosed as BLD. So here is the first in a series of BYGL BLD Diagnostic comparisons. We have discussed BLD in a number of previous BYGL-alerts (https://bygl.osu.edu/node/885), but here is a one on one comparison of look-alikes and diagnostic beech mis-reads.

 

BLD vs. A Leaf Curling Aphid.

 

I find this to be the most common BLD mis-read. I wish I could tell you the species of the aphid in this example: I cannot, but it is common in most beech woodlands on a few or many trees. At least I think it is the same aphid; it may very well be that there are a number of aphids that cause this leaf curling on beech. As you can see from the picture, the symptom on beech is the curling of leaf margins, with the sign of the aphid typically being cast skins of the aphids within the curled leaf. Presence of these aphids is not correlated with BLD.

 

As you can also see, there is a leaf discoloration symptom associated with the leaf curling. This is the key to it being mistaken for Beech Leaf Disease. The yellowing near the infestation is mis-interpreted as the “banding” symptom on BLD. With BLD though, there is clear banding of deep green and lighter greens, not this yellow banding noted from the leaf curling aphid.

 

This leaf curling aphid causes truly minimal damage to the plant. BLD, on the other hand is a serious problem, causing considerable progressive thinning of the canopy and in some cases tree death. So, check it out when you see beeches in the woods BTW, our landscape European (F. sylvatica) and Asian beeches (F. orientalis and others) have been diagnosed with BLD in nurseries.

 

Next time, let us remind ourselves of two other aphids that occur on beech: boogie-woogie aphids on American beech and woolly beech aphids on European beech. Also, neither of which is BLD.

 

BYGL Weekly News for September 24, 2018

The following articles were compiled during the last 7 days by members of the Extension, Nursery, Landscape, Turf (ENLT) team to benefit those who are managing a commercial nursery, garden center, or landscape business or someone who just wants to keep their yard looking good all summer.  Access the BYGL website for additional information on other seasonal topics at: http://bygl.osu.edu

For more pictures and information, click on the article titles.  To contact the authors, click on their names.

Ohio Pollinator Habitat Initiative – Annual Milkweed Pod Collection 

Authors Amy Stone

Published on September 19, 2018

The Ohio Pollinator Habitat Initiative (OPHI) is encouraging all Ohioans who have grown common milkweed this season to harvest seed pods and take them to a participating Soil and Water Conservation Office. The Annual Milkweed Pollination Collection is in its third year in Ohio. In 2015, 7 counties piloted the milkweed seed pod collection. The project has grown and it is estimated that over 22 million seeds have been collected by volunteers across the buckeye state over the 3 years.

Milkweed is the only host plant for the monarch butterfly for egg laying and the caterpillars rely on it for food. It also serves as a food source for monarchs butterflies, as well as many other pollinator species.

To make the collection as successful, the OPHI has come up with the following tips:

  • Make sure that before you collect seed, you become familiar with the common milkweed to avoid harvesting pods from similar plants such as hemp dogbane and swamp milkweed. The collection is for only the common milkweed.
  • It is best to collect the pods when they are dry, grey, or brown. IT IS IMPORTANT TO CHECK THIS! (Since pod collection starts September 1 and runs through October 31… please use September as the time to locate milkweed plants and to keep an eye on the pods while they ripen and then pick them once they look like the picture in the link.)
  • If the center seam pops with gentle pressure, they can be harvested.
  • Store the pods in paper bags; plastic bags collect unwanted moisture.
  • Put the date and county collected on the bag when you turn them in.
  • Keep the pods in a cool, dry area until you can deliver them to the nearest collection site.
  • You can find the nearest collection site at https://www.agri.ohio.gov/wps/portal/gov/oda/divisions/soil-and-water-conservation/find-a-local-swcd/swcd-list

 

These are the districts that are participating with the OPHI Pod collection this year as indicated in the salmon color above:

Adams, Ashland, Athens, Auglaize, Belmont, Brown, Butler, Carroll, Clark, Clermont, Clinton, Columbiana, Cuyahoga, Darke, Delaware, Fairfield, Fayette, Franklin, Fulton, Greene, Hamilton, Hancock, Harrison, Henry, Hocking, Holmes, Huron, Jefferson, Knox, Lake, Logan, Lorain, Lucas, Madison, Mahoning, Medina, Meigs, Mercer, Miami, Monroe, Montgomery, Muskingum, Noble, Ottawa, Paulding, Pickaway, Pike, Preble, Putnam, Richland, Ross, Sandusky, Shelby, Stark, Summit, Trumbull, Union, Van Wert, Warren, Washington, Wayne, Williams, Wood, and Wyandot

Collections began the first of September and will continue through October 30. If you have questions regarding milkweed collection, please contact Marci Lininger at Marci.Lininger@dot.ohio.gov or Lori Stevenson at Lori_Stevenson@fws.gov or reach out to your local Soil and Water Conservation District. Not familiar with the office in the county that you live? Check out their webpage to be able to search and find the location in your county: https://ofswcd.org/who-we-are/find-your-swcd.html

For more information on best practices for collecting milkweed please refer to this video! http://u.osu.edu/beelab/milkweed-seed/  Happy seed collecting!
 

More Information

Ohio Pollinator Habitat Initiative

http://www.ophi.info/home.html

OSU Bee Lab

http://u.osu.edu/beelab/

Monarch Joint Venture

https://monarchjointventure.org/

 

 

 

Rare and Unusual Caterpillar on Poplar

Authors Joe Boggs

Published on September 18, 2018

 

 

I had never seen or heard of the poplar tentmaker (Closter inclusa) until we ran into this unusual caterpillar on its namesake host during the Greater Cincinnati Diagnostic Walk-About last Monday at the Boone County Arboretum.  In fact, it took me a while to identify this seldom-seen defoliator.

 

I felt better about my lengthy ID challenge after reading what David Wagner wrote about the moth behind the caterpillar in his book, “Caterpillars of Eastern North America.”  He noted, “It is rare – should you find its caterpillar or secure livestock, take notes and images.”

 

Such is often the case with seldom seen native moths.  They fly below the radar until they or their caterpillars appear out of the blue to test our resolve for making an insect identification.

 

Wagner and other sources indicate the caterpillars feed on various members of the Populus genus as well as willows (Salix spp.).  We found the caterpillars feeding on a hybrid poplar (P. deltoidies x P. heterophylla ‘Rainbow River’).

 

The caterpillars are “tentmakers” in the truest sense of the word.  When I hear “tent-making caterpillars,” I think of silk nests like those produced by eastern tent caterpillars (Malacosoma americanum).  However, the poplar tentmaker actually constructs tents by using silk to stick together two or more leaves.  Then they line their dangling domiciles with a cozy layer of silk.

 

The caterpillars spend the day hanging out inside their protective silk-lined tents no doubt dodging predators and perhaps exchanging grand plans for after they pupate.  They venture forth at night to feed on leaves consuming everything except the main veins.  If not for the odd dangling “tents,” their leaf damage could easily be mistaken for damage caused by a general defoliator such as yellownecked caterpillars (Datana ministra).

 

The look-a-like leaf symptoms also extended to sawfly larvae we found on the same poplars populated by the tentmaker.  Thus far, I’ve not been successful in identifying the sawfly.  The larvae looked identical to the species, Nematus calais.  However, this species is reported to only feed on willow.  Regardless, had the sawfly larvae not been present, it would have been easy to assume all of the leaf damage was being caused by the tentmaker.

 

The poplar tentmaker has 3 – 4 generations in the southern U.S. and we saw evidence there are at least 2 generations in our part of the country.  The moth may be rare, but that does not mean its caterpillars will not occasionally cause noticeable defoliation.  However, reports indicate the most significant damage occurs late in the growing season after trees have already generated and stored enough carbohydrate to support the production of new leaves next season.  Consequently, the poplar tentmaker probably has a limited impact on the overall health of its host trees.

 

 

 

The Impatient Gardener

Authors Jim Chatfield  Jason Veil

Published on September 18, 2018

 

 

The genus Impatiens is quite familiar to most gardeners. From beds and borders of bedding impatiens, use receding and then rebounding some in recent years with the scourge of downy mildew disease, to the ever-more colorful types of New Guinea impatiens and their genetic resistance to downy mildew: these flowers are garden staples. There are also our native impatiens, the orange-flowered Impatiens capensis  and the yellow-flowered I. pallida, known as jewelweed or touch-me-not.

 

Jewelweeds have tell-tale gem-shaped fruits, water that beads on the leaves, leaves temporarily wilting like other impatiens during the heat of the sun, and fruits that explode upon touch to expel seeds outward from the mothership. Twice in the woods and roadside of Secrest Arboretum I have also seen a salmon-flowered variant of our native jewelweed, a product presumably of a random mutation.

 

So, imagine my wonder when while on Mackinaw Island in Michigan for a gardening conference recently I noticed a tall plant with narrow leaves and delightful pink and white flowers in flower beds looking up toward the Grande Hotel.  At first, I thought it was a type of snapdragon or other plant in the Scrophulariaceae with its unusual mouth-agape blossoms. Then the jewel-like fruits on the plants came into focus. A pink jewelweed?

 

Secrest curator Jason Veil had not seen this flower before either, but his cell-phone was handy. It was Impatiens glandulifera, the Himalayan jewelweed or Himalayan balsam (impatiens being in the Balsaminaceae family). We were all excited about learning of this new (to us) garden plant – a pink touch-me-not.  I must write about it, I thought. Alas, within the day, our horticulturist interest waned as we read on that this Himalayan native annual plant is now present across much of Europe and North America after introduction as an ornamental, with one source even labeling it as one of the most invasive species in the world.

 

I don’t know about that, but clearly it is invasive. Who knew? Not us. Our perspective changed from something we did not know of to admiration to not planning to further the spread in a matter of hours. Then a few weeks later, in the Denver Botanic Gardens, we noticed beds of two more Impatiens species, the yellow-and-white-flowered I. bicolor and the lavender-and-white-flowered Impatiens balfourii, both from India. Our impatiens knowledge continues apace.

 

 

 

 

Blue-Winged Wasps Cruising Lawns

Authors Joe Boggs

Published on September 17, 2018

 

 

Blue-winged wasps (Scolia dubia) are continuing to make low-level flights over lawns in southwest Ohio.  As their common name implies, the wasps have dark blue wings.  Their legs and thorax are also dark blue.  However, their most distinguishing features are two light-yellow spots on top of their orange-tipped abdomens.

 

The wasps usually fly a few inches above the turfgrass, often in loops or in a figure-8 pattern.  They may also be spotted landing on flowers to sip nectar, most often on common goldenrod (Solidago canadensis).

 

There are two beneficial aspects to this wasp.  It is a plant-pollinator as well as a parasitoid of white grubs with a particular affinity for green June beetle (Continus nitida) and Japanese beetle (Popillia japonica) grubs.

 

Once a grub is located during their low-level flights, the wasp digs into the soil until it finds the grub, or it will simply enter a green June beetle grub’s soil burrow.  Digging through the soil is not without consequences as evidenced by tattered wings.

 

The wasp first stings and paralyzes the grub, then it lays an egg on the grub’s body.  When the egg hatches, the wasp larva feeds leech-like on its hapless grub victim until the grub is no more.  Their negative impact on white grub populations can be significant.

 

Providing a good late-season nectar source, such as goldenrod, can help draw in this parasitoid wasp to draw down white grubs.  It’s a good example of how butterfly gardens (a.k.a. pollinator gardens) can serve as an important component in an overall pest management strategy.

 

 

 

A Non-Native, Native Lizard

Authors Joe Boggs

Published on September 17, 2018

 

 

If you’re ever visiting Cincinnati during the dog days of summer, keep your eyes peeled for a fascinating non-native lizard scurrying over rock walls, darting across sidewalks, and lurking in landscaping.  I’ve posted BYGL reports about these lizards in the past because the story of how they got to Cincinnati is so intriguing and their ascent to equal treatment amongst native reptiles is almost unprecedented for reptiles in Ohio.

 

The lizard’s common name is influenced by where you stand, literally.  If you’re an American herpetologist, you would call them European wall lizards (Podarcis muralis).  If you live in Europe, they are common wall lizards.  If you’re a native Cincinnatian, you would likely call them “Lazarus lizards.”

 

The lizards are capable of shedding part of their tail to survive a predator’s attack; a defense mechanism known as autotomy.  The detached tail will continue to whip back and forth to further distract (bewilder?) a predator.  A slight swelling of the tail often indicates where the old tail broke off and a new tale grew.

 

However, the local common name “Lazarus” has nothing to do with dropping a tail to rise again.  It’s associated with the Lazarus family best known in Ohio for their connections with department stores.

 

In 1951, 10-year-old George Rau Jr., step-son of Fred Lazarus III, came across some common wall lizards scurrying across rocky slopes while on a family vacation to Lake Garda in northern Italy.  George smuggled a few (6 to 10 depending on the reference source) through customs to release them at his family’s home on Torrence Court located in the eastern Cincinnati suburb of Hyde Park.

 

Some of the European expats thrived to eventually become so numerous that Torrence Court is still sometimes referred to as “Lizard Hill.”  Local residents called them “Lazarus lizards” in misplaced recognition of the lizard’s perceived patrons.  Of course, they should have been named “George’s Lizards” in honor of their true sponsor.

 

The lizard story may ring like local lore; however, George Rau wrote a letter in 1989 to herpetologists at the Cincinnati Museum of Natural History detailing his role as the lizard leader.  He also repeated his story in several interviews with the news media.

 

Research conducted by Cassandra Homan for her 2013 University of Cincinnati M.S. Thesis (see “More Information” below) added credibility to Rau’s claim.  She compared genetic samples collected from the Cincinnati lizards to samples taken from the reported source population in Europe and confirmed a substantial loss of genetic diversity indicating a genetic bottleneck.  Her computer simulations suggested the bottleneck was likely associated with only three individuals surviving their release to become the founders of the Cincinnati populations.

 

The European wall lizards mostly feed on insects which means they no doubt compete with one or more of our four lizard and skink species (order Squamata, suborder Lacertilia) native to Ohio.  The non-native lizards are now found in pockets throughout much of Cincinnati and parts of the adjoining states of Kentucky and Indiana.  Although their spread has been patchy owing to their requirement of rocky terrain or stone walls on south-facing slopes in order to survive winters, localized population densities may be as high as 1,500 per acre.

 

Indeed, the species has been so successful in colonizing southwest Ohio, it has achieved a rare status for a non-native.  The “European wall lizard (Podarcis muralis)” is listed among the names of native reptiles in Chapter 1531: Division of Wildlife; 1531.01 Division of wildlife definitions.  It is considered a “naturalized species” that is protected by law.

 

More Information

Bottlenecks and Microhabitat Preference in Invasive Wall Lizard, Podarcis mural…

https://etd.ohiolink.edu/ap/10?0::NO:10:P10_ETD_SUBID:89321

 

 

 

Tune In – What You Need To Know About Spotted Lanternfly (SLF)

Authors Amy Stone

Published on September 17, 2018

 

 

Last week, Emerald Ash Borer University (EABU) hosted a webinar on the Spotted Laternfly (Lycorma delicatula). The session has been recorded and is available online for viewing. The presentation is free, as well as other past EABU educational sessions.

 

The SLF session provided information for someone who is not familiar with SLF, and individuals with some background but would like an update on the latest developments. Just like other invasive species, we need to be alert to our own surroundings and if we see something that we suspect could be SLF or another invasive species, report it using the Great Lakes Early Detection App, contact the Ohio Department of Agriculture (ODA), or your contact in the local OSU Extension Office. The SLF has not been detected in Ohio, but we must remain on alert. This webinar is a great way to quickly get up to speed and know what to look for throughout the entire year.

 

The presenters for the SLF webinar were Heather Leach, Spotted Lanternfly Extension Coordinator and Dr. Julie Urban, Senior Research Associate, both of Penn State University.  They were able to share their knowledge and first hand experience on a pest we do not want in Ohio.

 

The webinar included the following information:

 

  • Life Cycle
  • Biology
  • Host Preference

o    Tree of Heaven

o    Black Walnut

o    Grapes

o    Apples

o    and more than 70 more plants

  • Damage

o    Plant Death and Decline

o    Yield Losses

o    Sooty Mold Accumulations

  • Current Research Update

 

The recorded webinar can be found online at https://www.youtube.com/watch?v=WSjKoBCukac

 

I found the session to be very useful and filled with practical information. The speakers included the photo below in their presentation. While I was taken back by the number of SLF adults in this photo, I reminded myself to be alert to not only these huge number that anyone would likely notice, but fine tune my diagnostic skills to look for the single specimen, the egg mass at quick glance could look like mud, or the unusually high activity of yellow jackets attracted to the honeydew produced by the SLF this time of the year.

 

You can help fight invasive species by learning more and engaging others about these pests.

 

If you are interested in the topic of invasives and want to learn more, check out future EABU sessions. of the fall schedule include:

  • Gypsy Moth: Past, Present and Future, Thursday, September 27, 11:00 am EST
  • Lingering Ash: EAB Resistant Ash Trees, Thursday, October 4, 11:00 am EST
  • Managing Ash Tree Post Emerald Ash Borer, Thursday, October 11, 11:00 am EST
  • The Asian Longhorned Beetle, Thursday, October 16, 11:00 am EST

 

Recorded sessions can be accessed through the emerald ash borer website: http://www.emeraldashborer.info/eabu.php

 

More Information

Penn State University Extension

https://extension.psu.edu/spotted-lanternfly

Pennsylvania Department of Agriculture

https://www.agriculture.pa.gov/Plants_Land_Water/PlantIndustry/Entomology/spott…

 

 

 

Redbud Leaffolder Damage

Authors Joe Boggs

Published on September 17, 2018

 

 

Participants at last week’s Greater Cincinnati Diagnostic Walk-About were thrilled to view the unusual leaf symptoms caused by the Redbud Leaffolder (Fascista cercerisella; order Lepidoptera; family Gelechiidae) on its namesake host.  Or, maybe it was just me who was thrilled.

 

While populations are not as high as in 2016, it is not uncommon to find redbuds with leaves turning brown after being folded over or “glued” together.  I’m not aware of any host preference studies for this native moth; however, the damage has always seemed more evident on weeping redbuds.  Of course, this could simply be due to the damage being more obvious because of the vertical orientation of the leaves.

 

Three overlapping generations of this velvety black moth occur per season in Ohio with 2nd and 3rd generation nests usually containing caterpillars in various stages of development.  Populations tend to build with each generation meaning that the most significant damage occurs late in the season.  The moth spends the winter as pupae in debris and fallen leaves beneath infested trees.

 

The leaffolder caterpillars produce nests described by their common name by using silk stitching to fold over leaf edges.  However, the nonconformist caterpillars also make nests like those produced by a “leaftier” by stitching together neighboring leaves.  In fact, in my opinion, the high frequency of tied-together leaves challenges the correctness of the caterpillar’s common name.

 

The caterpillars reside in heavy silk tubes within both types of nests.  They partially emerge out of their tubes to feed as skeletonizers, consuming the upper and lower leaf surfaces.  The affected areas turn orangish-brown which sharply contrasts with the normal dark green color of the foliage.

 

Early instar caterpillars are cream-colored and have no discernible markings.  As the caterpillars mature, markings begin to develop with alternating segments darkening to produce a striking appearance of black and light-green bands running the length of the body.  They resemble tiny banded sea kraits (snakes).  When disturbed, the caterpillars wiggle back and forth violently further enhancing their tiny snake impersonation.  They have great entertainment value!

 

Insecticidal applications are not generally required for managing this moth in Ohio landscapes.  Besides, the caterpillars live in protected locations which makes the successful use of insecticides problematic.

 

Most of the leaf damage is produced by the current 3rd generation caterpillars.  Trees have already generated and stored enough carbohydrate to support the production of new leaves next season.  Consequently, the leaffolder has a limited impact on the overall health of the tree even during localized population outbreaks.

 

Where practical, populations can be reduced by pinching nests to kill caterpillars.  Raking and destroying fallen leaves will also reduce localized numbers by eliminating overwintering moth pupae.

 

BYGL Weekly News for September 3, 2018

BYGL Weekly News for September 3, 2018

The following articles were compiled during the last 7 days by members of the Extension, Nursery, Landscape, Turf (ENLT) team to benefit those who are managing a commercial nursery, garden center, or landscape business or someone who just wants to keep their yard looking good all summer.  Access the BYGL website for additional information on other seasonal topics at: http://bygl.osu.edu

For more pictures and information, click on the article titles.  To contact the authors, click on their names.

Thousand Cankers Disease (TCD) Update – Don’t Rush to Cut Walnut Trees!

Authors Joe Boggs

Published on August 31, 2018

 

The long-term outlook for eastern black walnuts (Juglans nigra) seemed dire when the Thousand Cankers Disease (TCD) complex was confirmed in Butler County, OH, in 2013.  Thankfully, TCD has not followed the devastating trajectory we originally feared.  It is not rolling through our native black walnuts à la emerald ash borer (Agrilus planipennis) rolling through our native ash.  The two situations are like apples-to-oranges.

 

However, there have been some recent reports of Ohio landowners being approached by misinformed timber buyers and loggers citing TCD as a reason to cut and sell walnut trees.  There is no support for the pre-salvage harvesting of walnut trees.

 

Rather than following unsolicited advice, landowners should talk with a professional forester of their choosing before planning any timber harvest including the possible harvest of high-value black walnut trees.  The “Ohio Call Before You Cut” is a great resource ((877) 424-8288).  See “More Information” below for the website.

 

Background

 

The TCD complex involves a phytopathogenic fungus, Geosmithia morbida (Gm), carried from tree-to-tree by the Walnut Twig Beetle (WTB), Pityophthorus juglandis, which is a type of bark beetle.  Both are found naturally in walnuts native to the southwest U.S. such as Southern California black walnut (J. californica) and Arizona walnut (J. major).  However, since the trees, beetles, and fungus co-evolved, TCD does not kill these trees.

 

Such is not the case with eastern black walnut since it did not co-evolve with the TCD complex.  It is generally accepted that unprocessed wood from eastern black walnuts planted in the southwestern U.S. served as vehicles for the TCD complex to hitchhike to other locations in the U.S.  Although the exact route is unknown, it eventually arrived in Ohio.

 

As is common with bark beetles, WTB attacks its host’s stems in multiple locations with the females boring through the bark and tunneling through the phloem.  The Gm fungus carried by the beetles infects the surrounding phloem tissue producing small circular to oblong shaped dark brown cankers in the phloem tissue.  TCD is so-named because of the collective impact of multiple cankers:  “death by a thousand cuts” becomes death by a thousand cankers.

 

Despite its common name, WTB actually targets branches that are greater than 1/2″ in diameter.  They will also tunnel into the main stems.  The adult and larval tunneling and feeding activity produce symptoms typical of bark beetles with frass-filled galleries meandering through the phloem.

 

Traps baited with an aggregation pheromone that attracts both male and female WTBs have been available for a number of years.  They have been successfully used to detect new WTB infestations in the U.S. as well as evaluating the population densities and the spread of known infestations.

 

WTB was first detected by traps in Ohio late in 2012.  Thanks to a report from an alert landowner, infested and infected trees were found in August 2013.  Trap counts were impressively large within the TCD site.  For example, the beetle catch shown in the image below was over 1,000 beetles caught in one week.  This caused us all to believe TCD was a clear and present danger to our native black walnut trees.

 

However, in 2014, beetle trap catches dropped off dramatically and have remained low ever since.  Only 1 beetle was caught last year in multiple traps deployed to evaluate beetle populations in Ohio.  A similar dramatic drop in trap catches was observed that same year in eastern Tennessee where a much larger WTB infestation had been found some years before.  In fact, many heavily infested trees in Tennessee that were expected to die have recovered.

 

The reason for the sharp decline in beetles as well as the intensity of infections is not entirely known.  However, research conducted by University of Minnesota graduate student Andrea Hefty for her Ph.D. thesis revealed that WTB has low-temperature survival thresholds for both the adults and larvae.  Some have speculated that the southward shift in the North Polar Vortex during the 2013-14 winter season may have produced temperatures that crossed those thresholds.

 

Of course, black walnuts trees aren’t out of the woods yet.  Even though beetle trap catches are low, they aren’t zero.  There is always a chance beetle populations could rebound which is why Butler County, OH, remains quarantined.  Movement of walnut trees as well as wood products such as logs cannot be moved outside of the county within Ohio, or outside of the state, without conforming to quarantine restrictions.  For details, contact the Ohio Department of Agriculture (ODA).

 

Observe and Report

 

The possibility that TCD could rise again is why we must remain vigilant not just in Butler County, but elsewhere in Ohio.  Symptoms of TCD include yellowing foliage (chlorosis) that progresses rapidly to brown wilted foliage, and finally branch dieback.  Infected trees develop thinning canopies and top dieback with epicormic growth sometimes sprouting from lower portions of main stems.

 

Unfortunately, walnut anthracnose produced by the fungus, Ophiognomonia leptostyla, may be mistaken for symptoms of TCD and vice versa.  This is particularly important to keep in mind since the annual dropping of walnut leaflets and leaves due to anthracnose is well underway in southwest Ohio.  The fungus is specific to black walnut.  Unlike some of the other anthracnose diseases, walnut anthracnose is characterized by small dark brown spots rather than the larger irregularly shaped necrotic lesions seen with ash or oak anthracnose.  The spots are responsible for the alternate common name for the disease of walnut black spot.

 

However, don’t rely entirely on the images I’ve provided in this report to eliminate TCD from a diagnosis.  If you suspect TCD is affecting a walnut tree, you should contact our ODA.  It’s always better to report a suspected occurrence of TCD even if it turns out not to be rather than to ignore an actual TCD site out of fear of being wrong.  Remember that TCD in Ohio was originally discovered thanks to an alert landowner contacting our ODA!

 

More Information

Call Before You Cut

http://callb4ucut.com/ohio/

 

 

 

No Asian Hornets in the U.S.

Authors Joe Boggs

Published on August 28, 2018

 

 

When you read or hear about “Asian hornets,” you need to keep two things in mind.  First, the “Asian” moniker has been commonly applied to at least three hornet species native to various Asian regions.  These include the Yellow-Legged Hornet, which is sometimes called the Yellow-Legged Asian Hornet (Vespa velutina); the Asian Giant Hornet (V. mandarinia) which is the world’s largest hornet; and the Japanese Hornet which is a subspecies (V. mandarinia japonica).

 

The second thing to remember is that none of these hornets have been found living in the U.S. in spite of what you may find posted online.  However, this does not mean we shouldn’t be vigilant.  The yellow-legged hornet was discovered in France in 2004 and has spread into a number of other European countries.  It was found in Great Britain’s Channel Islands in 2016.

 

It’s a significant accidental introduction because this species, as well as the two other Asian species, behave as predators; they kill other insects and can wreak havoc on honey bee hives.  If you suspect that you’ve run across one of the Asian species, contact your state’s agricultural regulatory agency for instructions.  Official positive identification requires preserved specimens.  Frozen specimens are ideal if you can safely collect and freeze the suspects.

 

Cases of Mistaken Identity

 

Photographs cannot provide official positive identifications of a non-native Asian hornet; however, they can still be very useful.  I always recommend snapping some pictures and sending them to the appropriate entomology experts in your state.  I’d be happy to take a look at them if you’re in Ohio.

 

The two insects most commonly mistaken for Asian hornets are European hornets (V. crabro) and our native cicada killer wasps (Sphecius speciosus).  Cicada killers are the largest native wasp found in Ohio.  Their activity usually starts winding down at this point in the season; however, both the wasps and their robust namesake food item, dog-day cicadas (Tibicen spp.; family Cicadidae), remain in full-swing in southwest Ohio.

 

European hornets were first found in the U.S. in New York State around 1840.  Since that time, the hornets have spread to most states east of the Mississippi and a few states to the west.  European hornets are impressively large, measuring 1 – 1 1/4″ in length.  Their black and yellow markings on their abdomen make them look like yellowjackets on steroids; however, their head and thorax have distinct chestnut-colored markings.  Yellowjackets have black and yellow markings on the head and thorax.

 

Technically, this non-native is the only “true hornet” found in Ohio.  Taxonomically, our native bald-faced hornets (Dolichovespula maculata) are not hornets; they are grouped with yellowjackets which is why they are in the same genus as native Aerial Yellowjackets (D. arenaria).

 

Unlike our native yellowjackets and wasps, European hornets can cause noticeable girdling damage to twigs and branches of trees and shrubs by stripping bark to the white wood.  It is speculated that the hornets are extracting sugar from the phloem tissue.  Although the damage may be noticeable, it’s seldom significant enough to cause concern.

 

European hornets construct paper nests that may look similar to the bald-faced hornet nests.  However, they are most often found in hollow trees and sometimes in the walls of homes.

 

Normally, European hornets overwinter just like our native bald-faced hornets, paper wasps, and yellowjackets with only the queens that are produced this season surviving the winter.  The new queens leave the nests to seek protected overwintering sites; old nests are not re-used.  However, occasionally the entire European hornet nest will survive the winter if they are sufficiently protected.  Indeed, although it is rare, nests in Ohio have been observed surviving through three winters.

 

European hornets are reputed to be highly aggressive and their large size does make them look pretty scary.  However, during past encounters with this hornet, I was able to take close-up images and move branches with hornets on them without being stung or even charged.  Still, landscapers should be cautious around these large stinging insects.  Like wasps and yellowjackets, they are capable of stinging repeatedly.

 

The hornets may also fly at night and are attracted to porch lights or lights shining through windows.  They have been known to repeatedly charge windows at night inducing panic in homeowners.

 

Beware of the Web

 

Unfortunately, there are numerous spurious web reports of giant Asian hornets swarming through multiple U.S. states.  I do not believe these are intentional “fake news” reports; I believe most are cases of misidentifications or misunderstandings.

 

For example, you can find several online reports of the Asian stingers being found in Jersey.  That’s not New Jersey but one of the Channel Islands, officially the Bailiwick of Jersey in the English Channel.  It’s easy to miss such nuances while scanning web headlines.

 

 

 

Invasive Plant Species Alert – Japanese Stiltgrass

Authors Cindy Meyer

Published on August 28, 2018

 

 

Japanese stiltgrass was not on my radar until a recent visit to a local park. It had piqued my interest because of the lushness of the plants beneath a full canopy of trees. My first thought was, what is this grass that could be a recommendation for shady sights? My excitement quickly waned because our hosts explained that the annual grass unfortunately, is considered an invasive species. In fact, this non-native species from Asia, which was first found in Tennessee in 1919, can produce up to a 1000 seeds per plant and crowds out native plants. The seeds from this plant are dispersed by a number of mechanisms including foot traffic, water movement, equipment, and wildlife.

 

Japanese stiltgrass (Microstegium vimineum) can be found in disturbed areas such as; edges of fields, forests, ditches, recreational trails, etc. It grows in low-light environments with sufficient soil nutrients and moisture but it can also adapt to low-nutrient and low-moisture areas with adequate light.

Japanese stiltgrass leaves are flat, pale green, asymmetrically lance-shaped, and about 1–3 inches in length. Leaves are sparsely hairy on both sides and along the margins. A shiny, off-center, mid-rib is conspicuous on the upper surface, which is sometimes described as a silver stripe, and is a distinctive identification feature. Leaves are arranged alternately along the branched stem and project outward. Spikelike flowers up to 3 inches long develop in late summer or early fall in the axils of the leaves at the tip of the stem.  A shallow and fibrous root system is a distinguishing characteristic that sets it apart from the native white grass (Leersia virginica), which has a stout rhizome.

 

Management

Managing for Japanese stiltgrass is not unlike managing for other invasive plant species. It requires diligent, hard work! Inspection of equipment such as mowers, road maintenance equipment, and timber harvesting is important. Cleaning and sanitizing equipment with known stiltgrass infestations helps to prevent spreading of this grass. Hand-pulling is effective late in the season before plants flower. Pulled plants should be bagged. Mowing and/or weed eating is also effective if done before the plants mature and go to seed. Chemical control with non-selective herbicides, non-selective pre-emergent herbicides and selective grass-specific herbicides can be effective but may require more than one application over the course of a few years. When using any chemical always read and follow label instructions.

 

 

More Information

Ohio State University Extension – Ohioline Factsheet

https://ohioline.osu.edu/factsheet/F-70-11

Rutgers – Japanese Stiltgrass Control in the Home Lawn and Landscape

https://njaes.rutgers.edu/fs1237/

University of Maryland Extension – Home & Garden Information Center

https://extension.umd.edu/hgic/problems/japanese-stiltgrass

 

 

 

 

Broom of the Week; ‘Cody’s Feathers’ Baldcypress

Authors Jim Chatfield Jason Veil

Published on August 27, 2018

 

 

A baldcypress broom: no not a description of my hairstyle. Secrest Arboretum Curator Jason Veil and moi were at the Harper’s Collection of Dwarf Conifers at Hidden Lake Gardens of Michigan State University this past weekend. We of course looked at the Taxodium distichum ‘Secrest’ cultivar, but Jason also called me over to a lovely ‘Cody’s Feathers’ specimen, and pointed out what I certainly did not know – that it was originally spotted outside the Wayne County Hospital in Wooster.

 

Who ya gonna call? Well, how about he who found it there, lo a decade and a half ago: Bill Bargar of Wadsworth, a longtime member and website and newsletter writer for the American Conifer Society. We called Bill for background and a few wonderful pictures.

 

“Witch’s brooms” are strange, condensed, short-internode proliferation of shoots within the more typical growth of the plant, in this case a baldypress.  Many factors can cause broom-like growth but if caused by stable factors (such as a stable genetic mutation), then horticulturists see if they can usher a new version of the plant into the plant-lover world.

Bill who collected this broom, propagated it, and had it registered as a unique variant, the cultivar ‘Cody’s Feathers’, the cultivar name arising from his son’s description of the appearance of the feathery growth. Bill then grafted the cuttings to a compatible baldcypress rootstock.

 

This cultivar differs from other baldcypress brooms in its habit: as Jason describes it ‘Cody’s Feathers’ has a dense, shrub-like rounded habit that is unique. You can see this in Jason’s pictures from Hidden Lake. Bill’s images include a mature specimen at J.C. Raulston Arbortum at North Carolina State University, and the deep bronze-red color of foliage, highlighted in contrast to the blue-green cones.

 

BYGL Weekly News for August 20, 2018

The following articles were compiled during the last 7 days by members of the Extension, Nursery, Landscape, Turf (ENLT) team to benefit those who are managing a commercial nursery, garden center, or landscape business or someone who just wants to keep their yard looking good all summer.  Access the BYGL website for additional information on other seasonal topics at: http://bygl.osu.edu
 
For more pictures and information, click on the article titles.  To contact the authors, click on their names.
 
 
Authors Joe Boggs
Published on August 17, 2018
 
https://bygl.osu.edu/sites/default/files/styles/720/public/field/image/1%20Brown%20Marmorated%202014%202.jpg?itok=667japnP
 
I’m seeing damage on ripening tomatoes in southwest Ohio caused by Brown Marmorated Stink Bug (BMSB) (Halyomorpha halys) nymphs.  I first saw damage from both the adults and nymphs on my own tomatoes in 2015.  At that time, we didn’t know which direction BMSB populations would take in the southwest part of the state.  Would they become apocalyptic like in the Mid-Atlantic States or would they settle into becoming a “background” problem?
  
Thankfully, BMSB has followed a more moderate population trajectory in southwest Ohio compared to elsewhere with high populations confined to localized “hot spots” rather than being widespread.  However, that doesn’t mean BMSB can’t present a challenge to both backyard gardeners as well as commercial growers. Even low populations can produce noticeable damage making tomatoes unsalable or not usable as table fare by home gardeners.
 
Both nymphs and adults use their piercing-sucking mouthparts to puncture the epidermis and extract plant juices.  On green tomatoes, the damage may appear as whitish spots with indistinct borders.  Although the spots may only measure 1/16 – 1/2″ in diameter, they can merge to affect large areas of the fruit.
  
On ripe tomatoes, the damage appears as hazy golden yellow spots.  Stink bug damage may be superficial with little impact on the tomato flesh.  While damaged tomatoes are still edible, their unsightly appearance reduces their marketability.    However, heavy feeding may produce areas with whitish, spongy tissue, and feeding sites can initiate infections that enhance the “eww yuck” factor. 
 
BMSB management on tomatoes is a challenge owing to the often sudden appearance of damage to ripening tomatoes.  Heavy damage can occur before gardeners realize they have a significant bug problem.
  
There’s also a challenge with a limited number of insecticides labeled for use on ripening tomatoes.  You must always read and follow label directions paying particular attention to the time between the application and the harvest of vegetables called the “harvest interval.”  Unfortunately, this may preclude the use of many common insecticides if tomatoes and other targeted vegetable plants have ripened fruit that you’re planning to harvest.
 
Do not use traps thinking they will protect the tomatoes.  Research conducted by the University of Maryland showed they do the opposite:  they actually invite more bugs to the tomato party.  Likewise, if you’re growing patio tomatoes, keep the outside lights turned off at night.  They serve as “eat here” signs.
 
Finally, if you only have a few plants, the bugs can be managed by close inspections and digital control for the nymphs (use gloves!), or by using the “knock off and stomp” method for the adults.  I love the smell of stink bug in the morning!  Of course, you may want to leave your shoes outside.
 
 
 
 
Authors Joe Boggs
Published on August 17, 2018
 
https://bygl.osu.edu/sites/default/files/styles/720/public/field/image/1%20Stylized%20Orb%20Weaver%20Web.jpg?itok=OA8Dbasf
 
This is the time of the year in Ohio when female spiders of many web spinning species reach maturity.  They become most evident when their gossamer creations are illuminated by early morning sunlight reflecting off a heavy dew.
  
I was lucky to experience this magical but fleeting light effect during an early morning hike around my neighborhood a few days ago.  I was amazed by the sheer number of spider living near at hand.
  
There are over 600 species of spiders found in Ohio and most feed almost exclusively on insects.  The spiders that are currently dominating (draping over?) landscapes are the Sheetweb Weavers (family Linyphiidae); the Funnel Weavers (family Agelenidae); and the Orb Weavers (family Araneidae).
  
Orb Weavers
 
As their common name describes, orb weavers produce flat, circular (orb) webs.  The webs are intricate structures involving both sticky and non-sticky silk.
 
Non-sticky silk is used for “radial threads” which radiate from a central point like spokes on a bicycle wheel.  The non-sticky silk is also used for “frame threads” which encircle the web like a bicycle wheel to hold the radial threads in place and to attach the web to supports such as plant stems.  “Spiral threads” are composed of sticky silk arranged in a spiral pattern emanating from the center of the web; it’s the sticky silk that captures the spider’s prey.
  
A “stabilimentum” is a vertical pattern off dense silk centered in the web that is produced by many orb weavers.  The stabilimentum produced by the large, showy Black and Yellow Garden Spider (Argiope aurantia) usually has a zigzag pattern giving rise to the alternate common name of “Zigzag Spider.”  The dense webbing reflects ultraviolet light which attracts insects to their doom.
  
The closely related and similarly sized Banded Garden Spider (A. trifasciata) produces exactly the same type of orb web.  This spider is also native to Ohio; however, it’s not as common as its black and yellow cousin.
  
Look closely between the branch tips of shrubs and you may spot the diminutive Trashline Spider (Cyclosa spp.).  The silk in their stabilimentum enshrouds the drained bodies of previous victims; the morbid structure is responsible for the “trashline” common name.
  
The spiders rest in the middle of their trashline.  Their small size and mottled coloration makes them very difficult to see among their similarly sized and colored bundles of trash.  Indeed, research has shown that the trash bundles serve to confuse predators, such as birds and wasps, intent on making a meal of the spider, and the greater the number of bundles, the greater the confusion. 
  
Funnel Weavers
 
Funnel weavers produce large, flat, sheet-like webs spun across grass, under rocks or boards, or over the branches of shrubs such as yews and junipers.  The webs slope gently towards a narrow funnel or tube where the spider resides, awaiting its next victim.
  
The spiders are medium-sized and resemble small wolf spiders.  Funnel webs may measure more than 1′ across and can become very evident with dew, or when they snare dust during droughty conditions.
  
Sheetweb Weavers
 
Sheetweb weavers construct several types of webs depending upon the spider species.  Some species spin flat or slightly curved webs that overlay vegetation and rival the sizes of webs spun by funnel weavers.  However, there is no funnel in the web.  The spiders hide beneath one edge of the web, or in plant foliage along the edge of the web, to await their prey.
  
One of the more interesting sheetweb weavers is the bowl and doily weaver (Frontinella communis).  This is one of the few spider species with males capable of producing webs; however, females still dominate web weaving.
  
The spider constructs a complex web structure consisting of distinctly bowl-shaped webbing suspended from plant stems by a crisscrossing array of silk threads; this is the “bowl” in the common name.  The bowl is anchored below by a horizontal array of interwoven silk threads; the “doily.”  Flying insects drop into the web-bowl after bouncing in pin-ball fashion off the interlacing silk threads used to suspend the web.   Of course, when they drop into the web-bowl, they fall into the “arms” (and fangs!) of the awaiting spider!
  
Preserve; Don’t Kill
 
Spiders eat insects and research has consistently shown they remove a significant number of pests that we would have to deal with otherwise.  Of course, numerous arachnid engineered insect traps draped over low growing shrubs can look like Halloween decorations.
  
Continually removing the webs will eventually cause the spiders to take a hint and relocate elsewhere.  If you see the spider on the web, just shoo it off before destroying their web so you don’t accidently commit and arachnicidal act.
 
 
 
Authors Erik Draper
Published on August 15, 2018
 
Sweet corn with damage in the field
 
I was asked to help a vegetable grower figure out what was going on with something wreaking havoc and eating his ripening sweet corn.  Typically, when someone mentions sweet corn and problems, the first demon that comes to mind are those little masked, sweet-toothed bandits, known as raccoons!   When I arrived out in the field, I was surprised to see the corn stalks standing tall in nice rows.  The masked marauders climb up the cornstalk to the get to the ripest, uppermost ear of corn; consequently, the corn stalks are most often snapped off or pushed over down to the ground from the plump little pilferers!  It wouldn’t be so bad if they would munch the whole ear of corn, but nooo way!  They’ll take a couple of bites out of the ear, move on to the next sweet smelling corn stalk and the climb for corn continues through the night.  One hungry raccoon can damage numerous cornstalks and destroy 2-4 dozen ears of ripening sweet corn in a single night!
 
I digress, so as I walked out into the field there wasn’t a single corn stalk tipped over and I thought, “what in the heck is the problem… the corn is all upright!”  I then looked more closely at the actual ears of corn and saw the damage.
  
It was consistently about 18 inches to 2 feet off the ground and not a single ear had been bent down or torn off or ripped open.  The damage was more prevalent on the outside rows of sweet corn and was always on the side of the ear of corn and through the husks covering the ear.
 
The damage began as an elliptical area or opening and progressed up the ear until the husks split open to reveal the upper part of the ear.  Everything was neat and tidy and no half-munched kernels were on the ground or scattered around the base of the stalks.
  
The damaged ear continued to dry out and secondary pathogens then began to invade the open wounds and ruin the entire ear of corn.
 
Did you figure out the problem?  It baffled me until I found some damage near a huge mud puddle that held some tracks, then it fit together and all made perfect sense.
 
And now it will all make sense to you when you see the culprit…
 
I can image that this culprit will be invited to dinner for this year’s Thanksgiving day meal because it is already stuffed full with sweet corn!!  Should be quite tasty!
 
 
Authors Joe Boggs
Published on August 15, 2018
 
https://bygl.osu.edu/sites/default/files/styles/720/public/field/image/1%20Oleander%20Aphid%20Mandevilla%202018%202.jpg?itok=6G1tktut
 
My wife loves mandevilla (Mandevilla spp.).  The deep green foliage and showy flowers of these tropical or subtropical vines provide a nice trellised accent on our front porch.  So, when she told me one of our vines was under attack by hordes of sap-sucking aphids, I acted quickly … in the interest of domestic bliss.
 
As with any pest management effort, it’s important to identify the pest.  I was surprised to discover the aphids adorning the mandevilla stems were Oleander Aphids (Aphis nerii).  These bright yellow aphids are easy to identify with legs that look like they were dipped in black ink and black cornicles (siphuncules) which are the two “stovepipes” on the top of the back end of their abdomens.
  
Readers who grow common milkweed (Asclepias syriaca) for monarchs (Danaus plexippus) and other colorful native insects are no doubt familiar with this non-native aphid.  Indeed, it’s sometimes called the “milkweed aphid” for its preference for various members of the dogbane family (Apocynaceae); most notably plants in the genera Asclepias (milkweeds); Cynanchum (climbing milkweed, C. laeve), Vinca, and Nerium (oleander).
 
Of course, aficionados of plant taxonomy may be surprised that I was surprised to find oleander aphids on mandevilla.  That’s because I didn’t know these vining plants also belong to the dogbane family; until the aphids taught me.
  
This is not the first time oleander aphids provided me with a plant ID and taxonomy lesson.  I never knew there was such a thing as climbing milkweed until I stumbled across a vine in an Ohio woodlot festooned with these aphids.  Plant pests can be very helpful with making a plant ID.
  
Oleander aphids are parthenogenetic meaning there are no males; all are females.  This partially explains why this aphid can rapidly develop high population densities.  They also seem to be resistant to high summer temperatures which is unlike many other aphid species that are most prolific during the cool temperatures of spring and fall.
 
As their common name implies, oleander aphids evolved with their namesake Mediterranean host and draw chemical protection from their host plants.  The milky, sticky sap of oleander and milkweeds contains serious toxins called cardenolide glycosides.  As with a number of other insects that feed on plants in the dogbane family, oleander aphids incorporate the glycosides into their flesh as protection against predators.  It’s speculated that their bright yellow coloration warns predators against taking a taste.
 
On the other hand, some insects are unaffected by the aphid’s chemical shield.  Although research has shown the aphid’s honeydew contains cardiac glycosides, the chemicals do not dissuade some ants from “tending” the aphids in exchange for a sweet treat.
  
There are also several predators that are not dissuaded by the aphid’s toxic flesh including syrphid (hover) fly larvae, lacewings, and even some lady beetle larvae and adults.  Of course, some predators may be cowed by the ants.
  
A common nemesis of oleander aphids as well as a number of other aphids is the parasitoid wasp, Lysiphlebus testaceipes.  The wasp lays eggs in the immature aphids; one egg per aphid.  Parasitized aphids are called “aphid mummies” for their swollen, dark brown bodies enveloped in a dry, parchment-like exoskeleton
  
It’s important to preserve the aphid’s enemies.  So, I blasted the mandevilla stems with a solid stream of water to send the aphids on a wild water ride while declaring, “I am Zeus!”  I believe this impressed the Mediterranean aphids but may have surprised the neighbors.  Unfortunately, forcefully dislodging the aphids with water may only provide a temporary reprieve depending on the overall aphid trajectory.
 
In case water-logged aphids return, I’m holding in reserve other management options that are also “gentle” on aphid predators and parasitoids.  This includes using an insecticidal soap; purchased, not home-mixed.  Remember that soaps and detergents produced as cleaning agents may also contain chemicals that are harmful to plants.  Manufactures have no need to exclude these compounds because they are not producing products labeled for use on plants.  Knocking the leaves off my wife’s mandevilla using a “do it yourself” soap mix would not be beneficial to domestic bliss.
 
 
 
Authors Erik Draper
Published on August 14, 2018
 
Reblooming Magnolia 'Yellow Bird'
 
In the world of plants, most often our attention focuses on bloom color, size and timing of when blooms will make an impact in our landscape.  Blooms are nice as a moving focal point during the growing season, but people become a little upset when plants don’t do what they are supposed to and only when they are supposed to do it.  This is the time of year that concerned citizens call into the office wondering whether or not their magnolias or rhododendrons are going to die.  When asked why they think that the plants are going to die, the response is always the same, “because they are blooming again and they already bloomed this year!”
 
The official term for this startling behavior of plants blooming twice in a year when that is not typical, is “remontant”.  Therefore, remontant is another name for what we term “reblooming” plants.  Reblooming plants will bloom in their expected season and bloom cycle time frame and suddenly an unexpected second set of flowers appears later in the season!  In the landscape world, remontant plants are extremely desirable and this reblooming trait in new hybrid plants is intentionally selected for and sought out.
 
Remember that plants like magnolias, rhododendrons, forsythia and even crabapples, will set bloom for the next year, during our current growing season.  It is the formation of those blooms for next year, which often contribute to remontant tendencies of certain plants.  The blooms must be formed and ready to go by the time the plants shut down for winter.  With this “ready to bloom” approach, some plants after a strong growth phase or pause or a significant stress, seem to determine “I’m not waiting any longer… IT’S BLOOM TIME” and emerge.
 
Although we can admire that out-of-season bloom, bear in mind that if that specific, individual flower blooms now, then that specific, individual flower will NOT bloom again during its typical bloom time the flowing year.  A downside of remontant blooms is a slight reduction in overall flower numbers for next year’s floral display, depending on the number of flowers that actually bloomed out of season.  Rarely will remontant plants be totally without any flowers during their typical bloom time.  So get out there and enjoy that “crazy bloom”!

BYGL Weekly News for June 25, 2018

The following articles were compiled during the last 7 days by members of the Extension, Nursery, Landscape, Turf (ENLT) team to benefit those who are managing a commercial nursery, garden center, or landscape business or someone who just wants to keep their yard looking good all summer.  Access the BYGL website for additional information on other seasonal topics at: http://bygl.osu.edu

For more pictures and information, click on the article titles.

Burgeoning Beetles

Authors Joe Boggs

Published on June 22, 2018

I’m seeing large numbers of Japanese Beetles (Popillia japonica) in southwest Ohio.  Compared to previous seasons, the beetles appear to be more evenly distributed; they are not hard to find.  I’m hearing similar reports from the central part of the state.

 

I reported that beetles began to appear on the scene early last week which seemed a bit early [see BYGL Alert! “Masked Chafers and Japanese Beetles are on the Wing,” June 14].  It also seems early for high populations to be causing heavy feeding damage on leaves and flowers.

Japanese beetles were flying well below our radar prior to 2016 with rare reports of damaging populations.  That began to change in 2016 when we saw some heavy localized populations in many areas of Ohio [see BYGL Alert! “Japanese Beetles Making a Comeback,” July 7, 2016].

 

The beetle revival continued last year.  I reported that damaging populations were appearing in the southwest, central, and northeast parts of the state [see BYGL Alert! “Japanese Beetles Abound,” July 5, 2017].  Amy Stone (OSU Extension, Lucas County) wrote a follow-up report that high numbers of beetles were also being seen in northwest Ohio [see BYGL Alert! “More Japanese Beetle Abounding,” July 6, 2017].

 

Although Japanese beetles were widespread throughout the state in 2016 and 2017, their populations were highly localized.  A short drive could take you from a location with high numbers to another location with virtually no beetles.  Beetle populations seem less “patchy” this season with a widespread distribution and few “hot spots;” at least in southwest Ohio.

 

Damage is occurring on a wide range of host plants from sycamores to oaks to black locusts.  Although it’s easy to identify Japanese beetle skeletonizing damage while beetles are present on favored hosts like grape, damage may be more difficult to diagnose later in the season particularly on less well-known hosts

 

A Look into the Crystal Ball

Are we seeing the beginning of general Japanese beetle outbreak?  The short answer is we don’t know.  The long answer is that despite being a non-native, Japanese beetles have started to behave like natives in some areas of North America with populations rising and falling naturally.  As with native pests, there’s always the possibility for periodical outbreaks.  However, outbreaks can be unpredictable.

 

Ever since Japanese beetles were first discovered in North America in 1916 in a nursery near Philadelphia in Riverton, New Jersey, they have been gradually moving westward.  Trailing behind the beetles are a whole host of natural enemies.  Where the beetles have been living for a number of years, such as in Ohio, the natural enemies are able to act on this non-native pest just like natural enemies act on native pests.  So, populations can rise and fall dramatically from year-to-year. I believe that’s what we’re seeing:  a “natural” population rise that I predict will eventually fall.  How can I be sure?  Because, we’ve seen it before.

Families- A Grouping or Gathering of Similar Plants

Authors Erik Draper

Published on June 22, 2018

 

 

Have you ever thought “why in the world should I care about plant families?” Or why does it matter if a plant belongs to a certain family?  What if you were asked, “Can my Pyracantha (firethorn) shrubs get fireblight?”  or “What other plants could be possible target hosts for the Emerald Ash Borer”?  You will be able to understand the answers to these questions, IF YOU UNDERSTAND THE IMPACT OF PLANT FAMILIES!  You can answer with confidence the question posed, “Why in the world are oleander aphids feeding on my Balloon Plant Milkweed (Gomphocarpus physocarpus)?

 

On July 10, 2018 from 10am to 3:30pm, in the Secrest Arboretum Jack and Deb Miller Teaching Pavilion, Paul Snyder, Jason Vail, Jim Chatfield and Erik Draper will help to answer why plant lovers should care about knowing plant families too.  In this class session, we will discuss and look closely at the defining traits and characteristics of at least 15 different plant families commonly used in gardens and landscapes.

 

One key aspect to help with the identification of any plant is knowing the common traits of plant families and then we can ask the question “To which family does this plant belong?”  Understanding plant family traits and characteristics leads to understanding what plants need to not only survive but actually thrive in a landscape setting.  Each plant family has its own key characteristics like the number of flower petals, as well as the number and placement of stamens and pistils.   These characteristics each contribute to the correct identification of an unknown plant and become very useful in resolving certain diagnostic dilemmas.

 

For example, plants in the Ericaceae family, all have a very specific site and soil pH requirement that is required to survive.  If these requirements are brushed aside and ignored, these plants will, over a period of time, have their leaves gradually turn chlorotic, new twig extension will become shorter each year and eventually they will just die!  Can you guess those requirements?  Putting together a few members of the Heath or Ericaceae family helps to form an educated guess… So what do Kalmia, Vaccinium, Rhodendron, Einkanthus all require in order to survive?  They all need extremely low soil pH’s, moist but not saturated soils, high organic matter content, and well-drained soils.

 

Come join us and learn more plant family facts that will help to boost your confidence in choosing those “landscape plants that you always wanted in the garden” to be a success!

 

Cost of the class, which includes outstanding lunch cuisine, is $40.00 per person.  Contact Sarah Mays to register at 330-263-3831 email her at mays.201@osu.edu for more information.

 

 

Twisted Tale of Dodder

Authors Joe Boggs

Published on June 21, 2018

 

 

Dodders are parasitic plants belonging to the morning glory family, Convolvulaceae.  They were formerly placed in the dodder family, Cuscutaceae, with only one genus in the family, Cuscuta.

 

Depending on the reference, there are somewhere between 100 – 170 species worldwide with 13 species found in Ohio.  The two most common species found in our state are Common Dodder (Swamp Dodder), C. gronovii, and Field Dodder, C. pentagona.

 

Just how common are dodders in Ohio?  I don’t see them very often, but I welcome your input.  Please be specific with pictures and exact locations.

 

For example, I’ve been keeping track of what appears to be a single dodder species in the Otto Armleder Memorial Park, Great Parks of Hamilton County, 5057 Wooster Pike, Cincinnati, OH 45226.  All of the images and observations in this report were made at that location.

 

The hallmark of dodders are their thin, tendril-like stems that encircle the stems of their host plants.  Dodder stems range in color from yellow to orange to red depending on the dodder species and age.  Some, but not all species have tiny scale-like leaves.  Although most dodders have some chlorophyll, it’s insufficient to photosynthesize enough sugar to support a singular lifestyle.  Mature dodder plants also lack roots.

 

Dodders are obligate parasites; they can’t make a living without their plant hosts.  They invade their hosts using specialized, peg-like structures called haustoria (singular haustorium).  The dodder’s haustoria are considered modified roots and are used to extract water, carbohydrates, and nutrients from their host’s vascular bundles.

 

Of course, dodders do not start out looking like spent fishing line.  They are annual flowering plants with each flower producing 2 – 4 large seeds depending on the species.

 

Apparently, there is no obvious seed dispersal mechanism for the large dodder seeds.  Infestations in field crops and landscapes are often associated with the movement of soil, equipment, or water.  Indeed, dodders are often found along waterways and Armleder Park is located in the Little Miami River flood plain.

 

The large dodder seeds are loaded with carbohydrate to support the frail seedlings until they can locate a plant victim.  The seedlings produce a rudimentary root system, but if they don’t sniff out a host to latch onto with 10 – 15 days, they die.

 

I used “sniff out” deliberately because that’s exactly what they do.  Research published in Science in 2006 showed that dodder seedlings are capable of detecting plant volatiles released by prospective host plants.  The sensory mechanism used by dodder is not known, nor are the exact chemicals or mixture of chemicals that send an “eat here” message.  However, it was shown that dodder can distinguish between odors emitted by good hosts like tomato and non-hosts like wheat.

 

What Lies Beneath

 

Dodders are stealthy plant invaders using a move that’s been described as mimicking a computer virus.  Research published this year in Nature showed that dodders send microRNA into their hosts that silences the encoding of genes that would normally support defenses.  One of those defenses is a protein that clots the flow of nutrients to the site of the dodder’s haustoria.  Without the “anticoagulant” protein, the plants life blood keeps flowing into the dodder.

 

Dodder wreaks havoc on its plant hosts in other ways.  The dodder bridge between several hosts can serve as a passageway for plant pathogens including viruses and phytoplasma.  Plant stress caused by the heavy extraction of the host’s resources can weaken plants making them even more susceptible to plant pathogens as well as environmental calamities such as drought.

 

I may not see dodder as being widespread in Ohio; however, there is no doubt that dodder causes annual crop losses worldwide that are measured in tens of millions of dollars.  These parasitic plants have been found sucking the life out of over 100 species of plants including alfalfa, clover, soybeans, and even solanaceous plants in gardens such as petunias and tomatoes.

 

The annual life cycle of dodder starting with seed germination in the spring means dodder can be managed using a range of preemergent herbicides.  This is a common and effective approach used to suppress dodder in field crops and ornamental nurseries

 

However, research published in 2008 in the journal Flora casts some doubt that dodder always has an annual life cycle.  The researchers observed a possible perennial characteristic of clover dodder (C. epithymum) by overwintering vegetatively on its most common perennial host Scotch heather (Calluna vulgaris).

 

I observed the possible harboring of dodder within the woody stems of black willow (Salix nigra) last fall.  Dodder flowers were sprouting from woody nodules on the main stems.  The flowers were free from any direct connections to dodder stems.  I remain uncertain exactly what I was seeing and revisited the willows yesterday but could not find dodder tendrils emerging directly from the willow stems.  However, I will be monitoring the trees this season.

 

Twisted Friends with Benefits.

 

Dodders have some nefarious sounding common names such as wizard’s net, devil’s guts, hellbine, and witch’s hair.  However, they are not devoid of providing some benefits.

 

Research published in 2017 in the Proceedings of the National Academy of Sciences showed that dodder’s tangled threads can function as important lines of communication between connected plants.  When a plant was attacked by defoliating caterpillars, messages sent to other plants connected on the dodder web caused them to raise their defenses.  The caterpillars were less successful with attacking the pre-warned plants.

 

Dodders also contains a range of compounds that may be beneficial in human medicine.  They have long been used in Chinese folk medicine.  A review published in 2017 in Biomedicine & Pharmacotherapy reported dodders harbor molecules with possible therapeutic benefits including potential antiviral and anticancer activities.

 

Of course, some claims may be overblown.  In preparing this report, I came across dodder facial cream that promises to reverse skin aging.  I’m hoping to make a bulk purchase.

 

NOTE:  See “More Information” below for key selected research referenced in this report.

 

More Information

2006 Volatile Chemical Cues Guide Host Location and Host Selection by Parasitic…

https://www.fs.fed.us/rm/pubs_other/rmrs_2006_runyon_j001.pdf

2008 Hidden in the host – Unexpected vegetative hibernation of the holoparasite…

https://www.sciencedirect.com/science/article/pii/S0367253008001278

2017 A Review on Phytoconstituents and Biological activities of Cuscuta species

https://www.sciencedirect.com/science/article/abs/pii/S0753332217313185

2017 Plants under stress by parasitic plants

https://www.sciencedirect.com/science/article/pii/S1369526616301819

2017 Stem parasitic plant Cuscuta australis (dodder) transfers herbivory-induce…

http://www.pnas.org/content/114/32/E6703

2018 MicroRNAs from the parasitic plant Cuscuta campestris target host messenge…

https://www.nature.com/articles/nature25027

 

 

More Lace Bugs

Authors Joe Boggs

Published on June 19, 2018

 

 

Lace bugs do well in hot weather and they are certainly doing very well.  I’m finding population densities and levels of damage that are normally seen in July.  I posted a report on hawthorn lace bugs (Corythucha cydoniae) this past Saturday [see “Hawthorn Lace Bugs Affect More Than Hawthorns,” June 16].  This report highlights a few others.

 

Most lace bug species found in Ohio live on the lower leaf surface.  They are tiny insects with the adults measuring no more than 3/16″ long.  Lace bugs are so-named because of the lace-like pattern of veins and membranes in their wings.  The nymphs are even tinier and appear to be covered in small spikes.

 

Both the adults and nymphs use their piercing-sucking mouthparts to suck juices from the leaves.  Although feeding is done on the lower leaf surface, the damage appears on the upper leaf surface as tiny chlorotic spots (= stippling).

 

The first thing you may notice on infested trees are leaves with areas that look “bleached-out,” or leaves that are entirely white to light brown.  High winds and heavy rains can drive lace bugs to lower leaves, so the damage may be heaviest in the lower canopy.  Look closely to make certain you’re seeing stippling and not another plant problem such as powdery mildew.

The stippling may at first appear as distinct 1/4 – 1/2″ diameter spots on the upper leaf surface created by 1st instar nymphs feeding near the cluster of eggs from which they hatched.  Eventually, the stippling will coalesce to produce large white patches as the damage becomes more widespread.  Another feature of lace bugs are black tar-like fecal deposits that add to the unsightly appearance of heavily infested leaves.

 

Heavily damaged portions of the leaf, or entire leaves, will turn yellow to copper-brown.  High lace bug populations can produce enough leaf damage to cause early leaf drop, branch dieback, and even the death of small trees and shrubs.

 

Lace bugs can also be a serious nuisance pest.  They have a penchant for dropping from heavily infested trees onto unsuspecting hikers, picnickers, and patrons of outdoor bars and cafes.  They don’t feed on people, but they can use their piercing-sucking mouthparts to deliver a pinprick bite particularly if they fall between a person’s neck and shirt color.  Adding insult to injury, floating lace bugs can ruin a good Mai Tai.

 

A Rogues Gallery of Lace Bugs

 

Aside from the aforementioned hawthorn lace bugs, other lace bugs producing noticeable leaf damage in Ohio include:  basswood lace bug (Gargaphia tiliae), buckeye lace bug (C. aesculi); oak lace bug (Corythucha arcuata), sycamore lace bug (C. incurvata); and walnut lace bug (C. juglandis).  I’m also getting reports of chrysanthemum lace bugs (C. marmorata) on the rise in the central part of the state.

 

The buckeye, oak, and walnut lace bugs confine their feeding to their namesake hosts.  Sycamore lace bugs may be found on American sycamore and to a lesser extent on London planetree.  Basswood lace bugs feeds on all members of the Tilia genus; however, they have are particularly fond of silver linden (T. tomentosa).

 

Chrysanthemum lace bugs (C. marmorata) are unusual in two ways.  They are found on both the lower and upper leaf surfaces and they may feed on a wide range of herbaceous perennials in the Asteraceae family including asters, black-eyed Susans, goldenrods, and sunflowers.  These lace bugs may occur in greenhouses as well as landscapes.  Indeed, landscape infestations may originate in greenhouses.

 

Management

 

The lace bugs in this report can have 2 to 3 generations per season in Ohio with leaf damage ramping up with each successive generation.  This means it’s critical to target the current first generation with control measures to halt further damage this season.

 

Suppression includes simply applying a heavy jet of water to blast away the lace bugs.  Of course, adults have wings, so they can fly back to trees meaning more “water treatments” may be necessary.  Insecticidal soaps and horticultural oils are effective; however, direct contact is required.  So, make sure to target the undersides of leaves.  The same is true for pyrethroid insecticides; they are stomach poisons but lace bugs are sucking insects.

 

Some systemic insecticides such as acephate (e.g. Orthene, Lepitect) and the neonicotinoids dinotefuran (e.g. Safari, Transtect) and imidacloprid (e.g. Merit, Xytect) are effective against lace bugs.  However, imidacloprid must be applied with enough lead-time to allow the active ingredient to migrate to the leaves in a high enough concentration to kill the bugs; it may be too late.

 

Of course, before using any insecticide, you must read and follow label directions paying close attention to plant safety as well as avoiding impacts on pollinators.  This includes making certain sprays do not drift or runoff onto non-target flowering plants.

 

 

 

A Most Beautiful Beetle

Authors Joe Boggs

Published on June 18, 2018

 

 

Dogbane (Apocynum cannabinum) is the representative species for the dogbane family, Apocynaceae, which includes milkweeds and other plants that ooze sticky white sap ladened with poisonous alkaloids.  Indeed, Apocynum translates to “poisonous to dogs,” or “dog killer.”  Sap from dogbane is reported to have been used against ravenous feral dogs.

 

This is the time of the year when a close look at dogbane may reveal Dogbane Beetles; one of the most beautiful beetles found in Ohio.  Indeed, the beetle’s scientific name, Chrysochus auratus, loosely translates to “made of gold.”  This native beetle should be familiar to BYGL readers; it’s one of my favorite insects and I post at least one report about it each year!

 

The gorgeous iridescent beetles display a captivating array of colors that change with slight changes in your viewing angle.  True to their scientific name, they may look like gleaming droplets of gold, or glisten with multiple mixed shades of green, copper, blue, and red.

 

The secret to the myriad display of colors can be found just below the surface of the exoskeleton.  Beneath an outer translucent layer rests stacks of tiny slanting plates that cover color pigments.  Light rays striking the surface of the plates are reflected as a shimmering sheen, while light rays that bounce off the pigments produce various colors.  The result is a lustrous mix of ever-changing hews; a kaleidoscope of colors that are almost unmatched in the insect world.

 

Of course, the beetle’s colorful display isn’t meant to elicit “oohs and ahhs” from humans; it’s meant to signal, “don’t mess with me” to predators.  Dogbane beetles ingest the poisonous alkaloids (cardiac glycosides) in dogbane sap, store the chemicals in specialized glands, and then they secrete the noxious chemical brew when threatened by predators.  Their bright coloration advertises their nasty chemical defense strategy.  Using bright colors to send a warning message to enemies is known as “aposematic coloration.”

 

 

 

OHIO STATE UNIVERSITY EXTENSION

BYGL Weekly News for May 28, 2018

BYGL Weekly News for May 28, 2018

The following articles were compiled during the last 7 days by members of the Extension, Nursery, Landscape, Turf (ENLT) team to benefit those who are managing a commercial nursery, garden center, or landscape business or someone who just wants to keep their yard looking good all summer.  Access the BYGL website for additional information on other seasonal topics at: http://bygl.osu.edu

 

For more pictures and information, click on the article titles.

White Flower Day

Date Published: May 24, 2018
Authored by: Jim Chatfield

Whaaat. That first picture got your attention, did it not. Pawpaw flowers are not white!  But they are beautiful, and now past. To further digress, Michael Dirr wonderfully terms pawpaw flowers “lurid purple” in color, and purple is a color made up of red and blue, and after all, white light is made up of red, green, and blue, so a perfect lead-in to…

…This past weekend, when I took a walk through my yard, starting with a side area where there is a patch of lily-of-the-valley (Convallaria majalis). I took a sniff of the perfumey flowers (smell but do not eat – all parts are poisonous), then noticed that the patch was not as large as I suspected. In fact, at least half of the patch was wild lily-if-the valley (Maianthemum canadense).

I have seen this in woodlands often, but have ignored it probably for years in my yard, supposing it was Convallaria.  And spreading among these as well was sweet woodruff (Galium odoratum, the May wine herb), intruding on this scene. Three white flowers taking up the ground amidst lilac, striped maple, weeping katsura, kousa dogwood, and other ornamentals.

It got me thinking of what other white flowers were in the yard. And they were legion, including a dwarf Aronia, daisy fleabane volunteers, flowering dogwood, white violets, a spreading white azalea, may-apples, volunteer shrubby honeysuckles, raspberries about to bloom white from their buds, kousa dogwood which bloomed like crazy last year but gets an honorable mention here even though it is taking a year off, a volunteer euonymus, spring beauty wildflowers, and a Korean mountainash Rich Larson of Dawes Arboretum gave me over three decades ago.

And that is just to start. There were highbush blueberries, tiny, creamy bell-like flowers which have great fall color as an ornamental and three of which provide about a gallon of blueberries each year, or rather a half gallon one year and a gallon and a half the next. Fortunately we have good, acid soil.

There was the delightful fragrance and feathery flowers of white fringetree, a tree in the back of our two acres that I ridiculously thought was a small persimmon for a few years after planting.  Emerald ash borer affects this Chionanthus virgincus, a member of the Oleaceae, closely related genetically to its fellow family member, the genus Fraxinus (ashes).  The emerald menace has not affected our fringetree, at least not yet, despite three large mega-infested ashes in our yard we had removed two summers ago.

There are diminutive wild strawberry (Fragaria vesca) plants flowering now. They are more than matched by the beautiful fields of garden strawberries (Fragaria ananassa) for market just past the western edge of our property, courtesy of the ever-bountiful Rittman Orchard. Come June we shall Go Forth Young Man and Woman, to the U-Pick portion of their business as that most wonderful part of the year begins – the Berry Season.

Back to the woody plants: Bloom on our various crabapples was coming to an end then lo these four day ago, but even the spent blossoms of the Molten Lava crabapple demonstrated the elegance of these lovely flowering trees. Flowering dogwood (Cornus florida) was at the end of its reign in our front yard, but a somewhat wild forgotten area in our northern side-yard yielded a surprise. I had almost forgotten and had to relearn the beauty of the creamy butter yellow buds opening to white four-bracted inflorescences of Cornus alternifolia. Wow.

A lowly “weed” disqualified itself as such, at least for the purpose of this bygl-alert, for I want it for the length of time it takes us to see what this tiny white flower represents. It shows us below its plant family credentials. Common chickweeds (Stellaria media) is in the Caryophyllaceae, which commonly has the characteristic of cleft petals, as seen below, with its five petals superficially looking like ten. Other members of this family include, carnation, gypsophila, and many “pinks”.

Common chicweed

Note: If you want to see a wonderful YouTube of identifying the lawn weeds, common chickweed and mouse-eared chickweed, and the larger woodland wildflower, star chickweed, check out: https://www.youtube.com/watch?v=GJnp-lqdofM

Two of my wife’s favorite woody plants are the double-file viburnum amidst our crabapple grove and the ‘White Tigress’ striped maple overarching our picnic table. The flowers of this infinitely interesting maple (bark, stipules, leaves and leaf venation, form, fall color) are what caught my eye this time. I had not looked carefully at the chain of flowers about to become winged fruits. They have what I predsume to be two prominent exerted styles, the tips of which contain the stigmas receptive to pollen grains and the base being the ovaries which when ovules are fertilized will ripen around the developing seeds and become the fruits.

Doublefile viburnum blooms

Finally two usual suspects, except from a certain perspective. Dent-de lions, the French name chanelling the toothed leaves or lion’s teeth, or dandelions, are certainly beautiful in their blowball stage, though unpopular in this seed-spreading mode. And tiny, cream-white flowers of Rhamnus, also in that wild northern area of the ChatScape. But wait, it is diseased. Alas, not in a killing way: A rust fungus (you will have to wait to see it) that has infected this invasive woody plant. Whither will this fungus go next?  Stay tuned soon for some springtime rust alerts, as we segue from white to orange.

Asian Chestnut Gall Wasp

Date Published: May 22, 2018
Authored by: Carri Jagger

The Asian Chestnut Gall Wasp was introduced to North America in 1974 on imported chestnut cuttings. To date it has be identified in Georgia, Alabama, North Carolina, Virginia, Maryland, Pennsylvania, Kentucky, Tennessee and Ohio.

This pest can be distributed throughout the United States by transporting infested seedlings to new areas and by the exchange of infested scion wood used in grafting new trees.

The insect lays its eggs in the buds of chestnut shoots then galls develop on the shoot tips, leaves and catkins.  Nut production and shoot growth are greatly affected by the galls.  Once the adult insect emerges from the gall the dried spent galls become woody and can remain on older limbs for several years.  If the infestation is severe enough it can hurt the overall vigor of the tree and can even cause death.

The adult female wasp is about an eighth of an inch long and they lay a cluster of three to five eggs in the chestnut buds during early summer.  Several adults can oviposit in a bud which could add up to as many as 25 eggs per bud.  Eggs hatch in 40 days with the larvae remaining dormant until the following spring.  When the bud starts to grow the larvae induce gall formation on developing plant tissues.  Before the larvae pupate they feed on the inner gall tissue for 20-30 days.  The adult wasp emerges from the gall in late May to early June.

Management of the pest is very difficult and insecticides are ineffective in suppressing the gall populations.  There are natural enemies that attack and parasitize newly developing galls.  If you have Asian Chestnut Gall you can prune and burn the infested plant material this may slow further movement of this pest.

Information for this alert was derived from the University of Missouri https://extension2.missouri.edu/pa100 and the University of Kentucky http://pest.ca.uky.edu/EXT/ACGW/welcome.htm

Soil Temps Determine Planting Time

Date Published: May 21, 2018
Authored by: Erik Draper

One of the most often asked vegetable questions during this early season is “How soon can I plant my tomatoes and peppers in the garden?”  There are two reasons that the northeast Ohio gardener’s rule of thumb is “wait for Memorial Day” before planting out the tender annuals like tomatoes, peppers and green beans.  The first reason is the possibility of a frost is almost eliminated by waiting until Memorial Day.  Those tender annual plants like squash, tomatoes, green beans and peppers, cannot tolerate a frost event or even lower temperatures at all!

The other reason to wait is that the soil temperatures need to warm up.  Regardless of what daily highs the ambient air temperatures reach, the key limiting factor for early season plant growth is soil temperatures.  The simplest and best way to know when it is time to plant those “prize winning” tomatoes is to buy a soil thermometer and test the soil temperature at about 3-4 inches deep.

Brilliant sunshine, snow showers or cold rains, partly cloudy or completely overcast skies, all serve to impact our soil temperature coming out of the winter season.  It is all about sunshine heating the dark soils, followed by the mostly topical heat layer being gradually moved deeper through the soil profile via conduction.  This is the reason that soils covered with a mulch, are slower to warm up in the spring.  This is due to the mulch acting as a barrier or insulator that prevents the sunlight from directly striking the soil to heat it.

Research studies have provided insight for us to know that tomatoes seem to have problems uptaking phosphorus when soil temperatures, are around or below 50°F.  This lack of phosphorus in young, tomato transplants shows up as a purpling of the underside of the leaves of the plant.  Germination of vegetable seeds is also contingent upon soil temperatures.  This is why peas, radishes, broccoli and other veggies we call “cool-season crops”, have no problem germinating and thriving early in the spring with cooler temperatures.

Put squash, pumpkin, green bean or corn seeds in the ground under those same cool soil conditions and little to nothing happens!  Germination is very slow in these cold, spring soils and the seeds are often overwhelmed by the soil microbes and other decomposers, becoming their source of energy or food.  This is one of the reasons why they are referred to as “warm-season crops”.  The threshold or minimal soil temperatures appears to be about 60°F or higher, which will provide the necessary soil environmental conditions needed by warm-season vegetable crops to grow.

Have some fun in your garden and buy a soil thermometer and track the temperature of your garden soils throughout the growing season.  I think that you‘ll be astounded, amazed and fascinated by what you discover about the temperature trends of your garden soils!

Apples Don’t Fall Far from the Oak Tree

Date Published: May 21, 2018
Authored by: Joe Boggs

Several types of “oak-apple” galls are now obvious on the leaves of their namesake oak hosts in Ohio.  These unusual plant growths range in size at maturity from 1/2 – 2″ in diameter and are named for their resemblance to apples.

Oak-apples are constructed of leaf buds that have been hijacked by a gall-wasp (Family Cynipidae) to surround a single gall-wasp larva located within a seed-like structure positioned at the center of the gall.  The gall structure provides both a protective home and a food source for the developing gall-wasp larva.

Cutting the gall open will reveal the gall’s internal structure.  In general, there are two groups of oak-apple galls:  those with internal tissue composed of a mass of white fibers radiating from the central larval capsule, and those with tissue that strongly resembles the flesh of an apple; it is spongy and juicy.

The so-called Large Empty Oak-Apple Gall is produced by the gall-wasp, Amphibolips quercusinanis (syn. A. inanis).  Galls measures up to 2″ in diameter and arise from leaf buds on scarlet and red oaks.  The gall surface is light green and covered with purplish-red bumps.

The internal structure of this gall is composed of white fibers radiating from the central seed-like gall chamber.  Wasp larvae have chewing mouthparts; so what do the gall-wasp larvae eat? The inside of the gall chamber is lined with specialized cells called nutritive tissue which is constantly being replaced as it is consumed by the gall-wasp larva.  Imagine lounging in a room with pizzas constantly emerging from the walls.

As with all plant galls, oak-apple galls change their appearance once they reach “maturity;” the point where a mature gall-wasp emerges.  In fact, oak-apples are racing towards completing their appointed task this season in the southern part of the state.  They will soon dramatically change color from Granny Smith apple-green to caramel brown.  The mature, brittle galls are called “empty” because the filaments eventually disintegrate leaving an empty gall husk.

There are over 50 species of gall-wasps that are known to produce oak-apple galls in North America and there are probably at least 10-15 distinct species of oak-apple gall-wasps found in Ohio.  Each type of oak-apple is produced by a different species of gall-wasp and their individual handiwork is so unique the galls alone can be used to identify the gall-wasp to species with actually seeing the wasp.

For example, the Small Oak-Apple Gall is produced by the gall-wasp, Cynips clivorum.  This gall forms on the underside of leaf blades as you can see in the images below.  The gall surface is free of any spots or other markings; however, the internal structure is very similar to the Large Empty Oak-Apple Gall.

As with the vast majority of plant galls, oak-apple galls cause no discernable harm to the overall health of their oak hosts.  I believe they actually add ornamental value to their oak hosts, but I may be biased.

 

The Gall Backstory

Gall formation by wasps and other gall-making insects and mites is a complex and fascinating process that is not yet fully understood.  Thus far, no researcher has ever produced a plant gall without the aid of a gall-maker.

Part of the reason the gall-making process is so complex is because gall-makers produce chemicals that turn plant genes on and off at just the right time to direct gall growth.  The resulting galls provide both a protective home and nourishment for the next generation of gall-maker.

The chemicals exuded by gall-makers can only act upon “undifferentiated” meristematic plant cells.  Under the influence of these chemicals, the meristematic cells that were originally destined to become flowers, stems, or leaves in the case of oak-apples, begin marching to a different drummer.

Once the errant cells fall under the chemical spell of a gall-maker, there is no turning back; they will become gall tissue.  Conversely, this also means that gall formation cannot occur once meristematic cells are committed to becoming “normal” plant tissue.  Once leaves are produced, the leaf cells can’t become gall cells.  It’s one reason the leaf-gall season begins in the spring!

The vast majority of galls found on trees cause no appreciable harm to the overall health of their tree hosts.  Keep in mind that the galls are an outward result of a complicated physiological and chemical dance between the gall-maker and the plant host.

No human has managed to duplicate the work so handily done be a group of organisms that are often viewed with disdain.  If not viewed with a sense of wonder and fascination, at least insect and mite gall-makers should garner begrudging respect.  Imagine the plant secrets that would be unlocked if we could unlock the gall-maker’s secrets?

BYGL Weekly News for April 16, 2018

BYGL Weekly News for April 16, 2018

The following articles were compiled during the last 7 days by members of the Extension, Nursery, Landscape, Turf (ENLT) team to benefit those who are managing a commercial nursery, garden center, or landscape business or someone who just wants to keep their yard looking good all summer.  Access the BYGL website for additional information on other seasonal topics at: http://bygl.osu.edu

For more pictures and information, click on the article titles.

 

Turf Tips
Managing Crabgrass in Turf

Date Published: April 9, 2018
Authored by: Jeff Stachler

 

With these rains the lawn is beginning to grow and the weeds are not far behind.  Some of the earliest emerging broadleaf weeds have begun to emerge.  The biggest problem with weeds in turfgrass is reduced aesthetic value, although some weeds can out compete turfgrass when management is reduced.  Smooth and large crabgrass, yellow foxtail, and annual bluegrass are the most frequent annual grass weeds in turfgrass.

 

Smooth crabgrass emerges in the spring before large crabgrass.  Smooth crabgrass emergence begins slowly when soil temperatures in the upper inch of soil reaches 54F for seven days and moisture is available.  This 54F soil temperature occurs many times when the dogwood begin to flower and the forsythia flowers begin to fade.  The current soil temperature for Columbus, Ohio is 41F which is 7.6F lower than the 5-year average!  Visit this website to track soil temperature for your area: http://www.greencastonline.com/tools/soil-temperature .  Based upon the current 10 day forecast, crabgrass preventer does not need to be applied until sometime after April 10th and likely much later.  Waiting to apply crabgrass preventer until just before emergence will ensure control of smooth and large crabgrass later into the season.  Peak crabgrass emergence is from mid-May to July 1st.  Crabgrass preventer must be applied before plants emerge, otherwise it will not be effective.  After applying the crabgrass preventer irrigate the lawn to get the herbicide incorporated into the soil.

If crabgrass densities are high, a postemergence herbicide application may be required.  If you have used preemergence crabgrass preventer for many years and have successfully controlled the crabgrass, it may be wise to stop applying the crabgrass preventer and scout to see whether any crabgrass will emerge.  If it does emerge then apply a postemergence herbicide.  Crabgrass can be controlled with some postemergence herbicides, but timing and rate are very important to effectively control crabgrass.  Effective postemergence herbicides include Dimension, Methar 30, Acclaim Extra, MSMA Turf Herbicide, and Drive 75 DF, but some of these may be difficult to obtain.  Acclaim Extra can injure certain bluegrass varieties.  When applying postemergence herbicides be sure to obtain thorough coverage and do not mow for two days before and after the herbicide application.

 

 

 

Tigers on the Prowl

Date Published: April 14, 2018
Authored by: Joe Boggs

 

I spotted one of my favorite insect predators darting about on forest trails yesterday:  Six-Spotted Tiger Beetles (Cicindela sexguttata).  Their common name is well justified as these tiny “tigers” hunt, kill, and eat other insects.

 

The shiny beetles are more emerald green in color than Emerald Ash Borer (Agrilus planipennis) (EAB) causing them to be commonly mistaken for the non-native borer.  Indeed, these tiger beetles have excellent eyesight, quick speed, and they are agile flyers; traits that make it difficult for people to get a close look for accurate identification.

 

Six-Spotted Tiger Beetles have a curious affinity for hanging out on woodland trails; they can certainly liven up a walk in the woods.  The beetles have elongated bodies with the thorax about half the width of the front wings and abdomen.  They have long legs and their bulging black eyes (the better to see you with, my dear!) make them look like they’re wearing dark goggles.

 

As the common name implies, six-spotted green tiger beetles have white spots that are arranged along the trailing edge of the wing covers, three spots per side.  The spots are small and sometimes obscured by light bouncing off their highly reflective shiny green bodies.

 

This ferocious predator sports powerful sickle-shaped mandibles that are used to grab and dispatch luckless arthropod prey; a trait that is shared with other tiger beetles (family Carabidae (Ground Beetles); subfamily Cicindelinae (Tiger Beetles)).  A word of caution:  these carnivores can also use their impressive mandibles to deliver a painful bite to the hand of the overly curious.

 

Even the larvae of this tiny tiger are predators.  However, instead of actively hunting their prey, they conceal themselves in vertical burrows in the soil to await hapless victims.  When a meat item such as insects or spiders walks past, the tiger larva springs forth like a jack-in-the-box to grab dinner with their powerful mandibles.

 

The bottom line is that six-spotted tiger beetles are highly effective and important predators throughout their life cycle.  So, keep your eyes peeled for and hands away from these tiny tigers prowling our woodland trails … and don’t kill them since they are good guys!

 

For More Info:

·         University of Kentucky, Kentucky Critter Files

http://www.uky.edu/Ag/CritterFiles/casefile/insects/beetles/tiger/tiger.htm

 

 

Browned Boxwoods

Date Published: April 13, 2018
Authored by: Joe Boggs

 

Boxwoods with light brown to golden brown leaves are common this spring in Greater Cincinnati.  Some of the leaf browning is due to winter injury with foliage at the tips of branches, particularly at the tops of plants or on the windward side of plants, most heavily affected.

 

Some was caused by salt damage either directly with “ice melt” or rock salt inadvertently thrown onto foliage, or indirectly with “salt spray” carried onto foliage from nearby roadways.  Salt damage is sometimes, but not always, concentrated on wide side of the plant.

 

However, a close examination may also reveal the telltale blister-like leaf symptoms caused by the boxwood leafminer (Monarthropalpus flavus).  Leafmines may be found throughout the plants although the highest concentration also occurs on foliage at branch tips.

 

Normally, the blister mines turn brown a bit later in the spring.  However, I’m noticing this year that the blister mines are turning brown much earlier and there appears to be a connection to widespread winter injury.  I’m not certain if winter injury is magnifying the leafmining damage, or vice versa.

 

Gently separating the upper and lower leaf surfaces (the leafminer had already done most of the work!) will reveal the bright yellow leafmining larvae (maggots) of this midge fly wiggling around in their blister mines.  The larvae will soon complete their development and pupate.  The pupae are also bright yellow at first, but turn orangish-yellow as this stage nears completion.

 

This non-native midge fly was accidentally introduced into North America from Europe in the early 1900s and is now common throughout Ohio, particularly in the southern and central parts of the state.  Adults emerge at around the same time red horsechestnuts (Aesculus × carnea) and doublefile viburnums (Viburnum plicatum) are in full bloom (440 GDD).  Except for their bright orange abdomens, the adults superficially resemble miniature mosquitoes.

 

Females use their needle-like ovipositors to insert eggs between the upper and lower leaf surfaces of boxwood leaves.  Each leaf may contain multiple oviposition sites with several eggs per site.  These sites will become individual leafmines producing the blister-like leaf symptoms.

 

Eggs hatch in early-summer and the resulting larvae spend the remainder of the season consume interior leaf tissue as they develop through the 1st and 2nd instar stages.  Winter is spent as 3rd instar larvae inside the leafmines.  The larvae resume feeding in the spring and develop through a 4th instar stage.

 

Much of the leaf damage occurs in early spring with the ravenous larvae rapidly expanding their leafmines.  Multiple leafmines in individual leaves may coalesce causing the upper and lower leaf surfaces to delaminate over the entire leaf.  Individual mines may turn reddish-green at this time of the year with heavily mined leaves turning from yellow to orangish-brown causing the leafmining damage to be mistaken for winter injury.

 

A close examination of the leafmines at this time of the year may also reveal small translucent “windows” created by the larvae in the lower leaf surface.  The pupae will wiggle through these weak points to ease emergence of the fragile adults.

 

This pupal activity is responsible for one of the most unusual features of this midge fly:  reports of hissing, crackling, or rustling sounds coming from heavily infested boxwoods.  I’ve reported on this strange phenomenon in past BYGLs.  So, reports from gardeners or landscapers that they’ve heard boxwoods going snap, crackle, and pop should be taken seriously as the odd sounds are an indicator of a heavy boxwood leafminer infestation.

 

Damaging boxwood leafminer infestations can be suppressed through applications of neonicotinoids such as imidacloprid (e.g. Merit, Xytect, Marathon, and generics) or dinotefuran (e.g. Safari, Transtect, Zylam).  However, application timing has been modified in recent years to avoid negative impacts on pollinators.

 

Boxwood blooms attract a wide range of pollinators; blooming plants can literally buzz with their activity.  Therefore, the insecticide applications must be delayed until AFTER boxwoods bloom.  Some minor miner damage will occur, particularly with the imidacloprid that is taken-up more slowly compared to dinotefuran.  However, this is a small price to pay for protecting pollinators.

 

You may find recommendations for topical applications of pyrethroid insecticides such as bifenthrin (e.g. Talstar) to target adult leafminer females before they lay eggs.  However, adults typically emerge in Greater Cincinnati while boxwoods are in full bloom, so I no longer recommend this application.

 

Plant selection provides a more long term solution to the depredations of boxwood leafminer by removing insecticides from the management equation.  A helpful research-based listing of the relative susceptibility of boxwoods to the leafminer was published in 2014 by the American Boxwood Society in their “The Boxwood Bulletin” [see More Information below].

 

For More Info:

·         American Boxwood Society, Boxwood Leafminer Evaluation

http://www.boxwoodsociety.org/uploads/54_1_2014_Summer.pdf#page=9

 

 

Watch Your ASH!

Date Published: April 16, 2018
Authored by: Thomas deHaas

 

Many of the Green Ash trees, Fraxinus pennsylvanica are dying in Perry, Ohio – Lake County. Why?

Green ash is popular as a shade tree in residential areas because of its good form and adaptability to a wide range of sites.

 

It is susceptible to Emerald Ash borer, an invasive species.

 

Emerald ash borer (EAB), Agrilus planipennis Fairmaire, is an exotic beetle that was discovered in southeastern Michigan near Detroit in the summer of 2002. The adult beetles nibble on ash foliage but cause little damage.

5449380 Debbie Miller, USDA Forest Service, Bugwood.org

 

The larvae (the immature stage) feed on the inner bark of ash trees,

5471796 Kenneth R. Law, USDA APHIS PPQ, Bugwood.org

 

disrupting the tree’s ability to transport water and nutrients.

Emerald ash borer probably arrived in the United States on solid wood packing material carried in cargo ships or airplanes originating in its native Asia. As of August 2017, it is now found in 31 states, and the Canadian provinces of Ontario and Quebec. Since its discovery, EAB has:

·         Killed hundreds of millions of ash trees in North America.

·         Caused regulatory agencies and the USDA to enforce quarantines and fines to prevent potentially infested ash trees, logs or hardwood firewood from moving out of areas where EAB occurs.

·         Cost municipalities, property owners, nursery operators, and forest products industries hundreds of millions of dollars.

http://www.emeraldashborer.info/

Symptoms include defoliation, D-shaped exit holes in the bark,

wood pecker damage (as they hunt for the larvae)

and ‘blonding’, which is large portions of bark that fall off the tree reveal a patch of wood that looks ‘blond’ in color.

A tree that shows severe infestation will die within the year. The danger is these trees soon become a fall hazard and need to be removed before injury or property damage occurs. It is recommended that you hire a tree removal service that is ISA certified and/or bonded.

 

Now that the Emerald Ash Borer has infested Lake County, Ohio, many Green Ash trees in the landscape and forest woodlots have died. But the real danger is right overhead.

 

With dead trees and wind combinded, it can be a costly and deadly combination. A tree that shows severe infestation will die within the year. The danger is these trees soon become a fall hazard and need to be removed before injury or property damage occurs.

 

Our understanding of how EAB can be managed successfully with insecticides has advanced since this bulletin was initially published in 2009. This version has been revised to address frequently asked questions and reflect the current state of understanding of insecticide options for controlling EAB and their effectiveness. It is important to note that research is an ongoing process. Scientists from universities, government agencies, and companies will continue to make discoveries and advance EAB management and ash conservation.

http://www.emeraldashborer.info/documents/Multistate_EAB_Insecticide_Fact_Sheet.pdf

 

 

They’re Baaack!

Date Published: April 10, 2018
Authored by: Joe Boggs

 

Last Friday, Larry Parker (Cincinnati Parks) sent to me the images below of Boxelder Bugs (Boisea trivittata, order Hemiptera) hanging out on a park building.  ‘Tis the season.

 

These boxelder bugs didn’t fly to the building this spring; they were already there.  This fall home invader overwintered somewhere in the building (walls, attic, etc.) and spring temperatures are beginning to roust them from their winter barracks.  The bugs were clustered as they awaited outdoor temperatures that will support their flight; they were gone from the building as of yesterday.

 

The bugs Larry photographed had successfully made their way outside, but this is not always the case.  Occasionally, they become confused by warm indoor temperatures and find their way into homes and other structures.  They don’t bite or represent a threat to anyone or anything inside a structure, but they can be serious nuisance pest as they frantically crawl or fly around looking for a route to the great outdoors.

 

This is the first report I’ve received this spring of boxelder bugs emerging from their overwintering sites.  However, with the predicted warm-up this week, I’m sure this is just the beginning.

 

We can also expect other fall home invaders to soon make their spring appearances.  These include Western Conifer Seed Bugs (Leptoglossus occidentalis); Multicolored Asian Lady Beetles (Harmonia axyridis); and the notorious Brown Marmorated Stink Bugs (Halyomorpha halys).

 

Boxelder bugs range in size from 1/2″ – 3/4″ long.  They are narrow-shaped, flat-backed, and dark gray or dark brownish-black.  They have three highly visible orangish-red stripes running lengthwise on the pronotum, the area behind the head; “trivittata” is Latin for “three-striped”.

 

The bugs are seed-feeders and are so-named because of a strong association with Acer negundo; however, both the adults and nymphs will commonly use their piercing-sucking mouthparts to draw juices from the seeds of other trees in the Acer genus.  They have also been observed feeding on alder, apple, buckeye, cactus, geranium, grape, honeysuckle, lilac, linden, oak, peach, plum, spirea, strawberry, and tulip.  I’m aware of boxelder trees being cut down in an attempt to eliminate the bugs; however, their wide-ranging feeding activity illustrates why this management effort may fail.

 

The best offense against these and other fall home invaders buzzing or lumbering around inside homes and other structures is a strong defense.  Large openings created by the loss of old caulking around window frames or door jams provide easy access into homes.  Such openings should be sealed using a good quality flexible caulk.

 

Poorly attached home siding and rips in window screens also provide an open invitation.  The same is true of worn-out exterior door sweeps including doors leading into attached garages; they may as well have an “enter here” sign hanging on them.  Venture into the attic to look for unprotected vents, such as bathroom and kitchen vents, or unscreened attic vents.  While in the attic, look for openings around soffits.  Both lady beetles and stink bugs commonly crawl upwards when they land on outside walls; gaps created by loose-fitting soffits are gateways into home attics.

 

For More Info:

·         University of Minnesota Fact Sheet

https://www.extension.umn.edu/garden/insects/find/boxelder-bugs/

BYGL Weekly News for April 9, 2018

BYGL Weekly News for April 9, 2018

The following articles were compiled during the last 7 days by members of the Extension, Nursery, Landscape, Turf (ENLT) team to benefit those who are managing a commercial nursery, garden center, or landscape business or someone who just wants to keep their yard looking good all summer.  Access the BYGL website for additional information on other seasonal topics at: http://bygl.osu.edu

For more pictures and information, click on the article titles.

Hort Shorts
Mulch Volcanos are Erupting

Date Published: April 7, 2018
Authored by: Joe Boggs

Why in the name of all that is horticulturally holey do we continue to see mulch piled around tree trunks to stratospheric heights?  What is the appeal?  And, why can’t we stamp out these mulch monstrosities despite years of educational efforts?

The image below was taken 20 to 25 years ago by Jim Chatfield using a 35mm camera.  It shows Erik Draper’s size 12 shoes positioned to illustrate mulch piled over 2 feet high. The three of us used this image for years in numerous training programs to teach against this horticultural horror (volcano mulch, not Erik).

Of course, there have been numerous efforts by other Extensioneers, Master Gardeners, and our Green Industry to educationally eradicate mulch volcanoes (a.k.a. mulch mounds).  There has been some success.  I can count on provoking groans from audiences of horticulture professionals or Master Gardeners by showing them pictures of mulch volcanoes.  The impact is so profound, I commonly hear groans lingering throughout my presentations!

And yet, mulch volcanoes continue to erupt.

Indeed, this mulch rant was incited by a visit to a local hospital yesterday where my wife had a minor medical procedure.  Nothing serious, but I spent the wait-time cruising the hospital’s landscape.  Unfortunately, the most striking feature was new mulch formed into high mounds:  mulch volcanoes were erupting everywhere!

Adding insult to injury was the peculiar practice of digging a “mulch moat” around the base of the mulch stratovolcanoes.  Creating these mulch moats not only cuts existing tree roots extending into the surrounding soil, but the trench can prevent root regrowth into the soil beyond the moat.  In essence, each tree has its entire root system confined to the area beneath its mulch volcano.  ARRGHH!

I’m certain the hospital is staffed by some of the best medical professionals in our region.  However, as visitors and patients approach the hospital, they are greeted by clear evidence of far less than professional horticultural practices.

When It’s Done Right

Organic mulches such as aged bark mulch are a wonderful thing.  They moderate soil temperatures, preserve soil moisture, suppress weeds, and as the organic mulch slowly decays, it contributes to the organic content of the underlying soil.  The dark color of natural bark mulch also enhances landscape aesthetics.  Of course, the availability of organic mulch dyes makes other colors available; shopping for mulch can be like using an artist’s palette.

 

Last season, I highlighted an exemplary use of mulch in Glenwood Gardens, Great Parks of Hamilton County (see BYGL April 27, 2017, “Glenwood Gardens: A “Volcano” Mulch-Free Zone”).  They had followed all of the general recommendations for the proper use of hardwood mulch around trees.  The mulch rings were as large in diameter as practical and mulch depths were no more than 2 – 3 inches.  Mulch that found its way onto the tree trunks was pulled away from the trunk flare.

When It’s Done Wrong

Volcano mulch does not kill trees outright; if it did, people wouldn’t do it.  Instead, it produces subtle, long-term, ill-effects.  Although bark mulch may at first appear light and airy, it will ultimately compact as it degrades to interfere with oxygen reaching tree root cells.  Trees respond by growing roots into the mulch; however, the roots can become exposed as the mulch further degrades.

The slopes of mulch volcanoes cause roots to turn; they can’t grow into thin air!  Eventually these roots encircle the tree trunk and merge with the stem tissue.  As these errant roots increase girth, they gradually girdle the trunk and restrict vascular flow.  Thus, they are known as “stem girdling roots.”

As the mulch decomposes and dries out, it will eventually start to repel water; it becomes hydrophobic.  You can observe the hydrophobicity of dry organic matter when you try to moisten a bag of dry peat moss.  Of course, water repellency ultimately causes roots that have grown into the mulch to dehydrate.

The deleterious nature of volcano mulch is not immediately apparent.  Moisture starvation and vascular strangulation can ultimately kill a tree; however, along the way they produce tree stress.  This can induce trees to drop their defenses against infestations by opportunistic insect pests such as native borers or infections by plant pathogens.  Of course, pests and diseases get blamed if trees succumb, not the volcano mulch that made the trees susceptible in the first place.

William Shakespeare, in King Henry VI, Part III, provided the perfect quote:

And many strokes, though with a little axe,

Hew down and fell the hardest-timbered oak.”

Volcano mulch is a little axe.

Weed of the Week – Hairy Bittercress

Date Published: April 6, 2018
Authored by: Amy Stone

Hairy Bittercress (Cardamine hirsute)

While temperatures remain cold, and even an occasional snow flake takes flight, there is weed that is giving it is all this spring. That weed is hairy bittercress. While it has been lurking in gardens all winter long, it is flowering its little heart out and setting seeds right now in northwest Ohio.

This weed sends out leaves in a basal rosette from seeds that germinated last year. Like other members of the mustard family (Brassicaceae), its tender greens are edible. You might be fooled by the common name—the plant is typically not bitter, but rather peppery in taste. Its flowers can be tough to chew, but the tender leaves are said to be a source of vitamin C, calcium, magnesium, beta-carotene and antioxidants.

Speaking of flowers, hairy bittercress produces a small cluster of tiny flowers each with 4 white petals. Narrow seed pods stand tall above the flowers. When dried or disturbed, the seed pods “explode” sending seeds in all directions.

This seed dispersal strategy is known as ballochory. Jewelweed and cranesbill also employ this as a strategy to spread seeds.

Removing plants prior to them setting seed is highly recommended. In northwest Ohio you will have to move pretty quickly as it doesn’t take much time for the seeds to develop. The use of a pre-emergent herbicide can help reduce future populations. Hairy bittercress can be a nuisance in the landscape, turf, greenhouse and nurseries.

Purple Haze All in My Eyes

Date Published: April 6, 2018
Authored by: Joe Boggs

Driving south on I-71 Wednesday, I was mesmerized by a deep purple veil creeping across fields like smoke on the water.  The purple haze, all in my eyes, made me wanna drive ’til I ran out of highway into the purple sky.

The annual bloom of Purple Deadnettle (Lamium purpureum) that is just getting underway in farm fields flanking Ohio’s southern highways was responsible for my nostalgic pop culture smash-up.  Even this weed’s name would be great for a rock band; think Deep Purple meets deadheads.

Purple deadnettle is a winter annual meaning that seeds germinate in late summer to early fall.  Members of this sneaky group of weeds grow throughout the winter and sing their flower song in the spring.  This isn’t a problem for farmers because winter annuals are easily plowed under in the spring so they don’t compete with summer annual crops.  In fact, in some ways, they act like winter cover crops.

However, winter annuals can create headaches for landscape and turfgrass managers.  Since preemergent herbicides are typically used to target the spring germinating seeds of summer annuals (e.g. crabgrass), winter annuals such as deadnettle can escape to reappear as harbingers of spring each year.

The beautiful purple display beginning to adorn Ohio farm fields is produced by both the flowers and new leaves of purple deadnettle.  The pitcher-shaped flowers range in color from pink to deep purple.  Older leaves are green to purplish-green while new leaves may be a deep, reddish-purple.

Henbit (L. amplexicaule) is sometimes mistaken for purple deadnettle, and vice versa.  Both are winter annuals and since both are members of the mint family (Lamiaceae); they have square stems.  However, henbit leaves are scalloped and evenly spaced along the stem; new leaves do not have a purple hue.  Plants tend to grow low to the ground and are seldom so prolific they cover large expanses of open ground.

The leaves of purple deadnettle are triangular to heart-shape and serrated along the margins.  They arise opposite of one another along the stem and new leaves may be deep purple.  Deadnettle plants may rise to height of 16 – 18″ and they commonly carpet open ground such flower beds, openings in weakened turfgrass, and of course farm fields.

Purple deadnettle can be controlled by hand weeding and cultivation.  A post-emergent broadleaf herbicide can be applied in early spring to control the blooming plant, but a pre-emergent herbicide will need to be applied in late summer to control the germinating seeds of this winter annual.  If you do choose to use an herbicide, be sure to follow and read all label directions.

Cold Weather Offers an Extension on Poison Hemlock Management

Date Published: April 2, 2018
Authored by: Joe Boggs

Our slowly developing spring is a real boon to us procrastinators.  If you exercise caution by performing a close inspection of what lies beneath, there may still be time to make a non-selective herbicide application to control Poison Hemlock (Conium maculatum) without wiping out preferred plants that have not yet sprung for spring.

Poison hemlock is certainly a worthy target for early spring herbicide applications.  It’s one of the deadliest plants in North America.  You don’t want this nefarious non-native invasive weed flourishing in landscapes where people; particularly children, can come into contact with the sap, seeds, foliage, or roots.  It’s no exaggeration to say the outcome could be lethal; consider Socrates.

Death in a Tea Cup:  A Greek Tragedy

The plant contains highly toxic piperidine alkaloid compounds, including coniine and gamma-coniceine, which cause respiratory failure and death in mammals. Indeed, the infamous demise of Socrates is testament to the lethality of poison hemlock.  Plants and seed were imported to North America as an ornamental from Europe and West Asia in the late 1800s.  Unfortunately, this dangerously toxic plant is now common throughout much of Ohio.

The toxins must be ingested or enter through the eyes or nasal passages to induce poisoning; they do not cause skin rashes or blistering.  Regardless, this plant should not be handled because sap on the skin can be rubbed into the eyes or accidently ingested while handling food.  While the roots are more toxic than the leaves and stems, all parts of the plant including the seeds should be considered dangerous.

Death-Defying Identification

Poison Hemlock belongs to the carrot family, Apiaceae (formerly Umbelliferae).  It shares a number of characteristics with the non-native but non-toxic Queen Anne’s Lace (Daucus carota) as well as the non-native Wild Parsnip (Pastinaca sativa) which is notorious for producing sap that causes skin blisters through phytophotodermatitis.

All stages of the poison hemlock plant have bluish-green leaves that are 3-4 times pinnately compound, and the deeply cut parsley-like leaflets have sharp points.  Flowering plants have hairless, light-green to bluish-green stems that are covered with obvious purplish blotches.  Clusters of tiny white flowers are borne on structures called umbels that look like upside-down umbrellas.

Turning the Tables:  Poisoning Poison Hemlock

Poison hemlock has a biennial life cycle and spends its first year as a basal rosette; the stage that is currently very apparent.  During its second year, plants produce erect, towering stalks and multi-branched stems topped with umbrella-like flowers.  Mature plants can measure 6-10′ tall.

Poison hemlock can be managed by mowing and tilling; however, the most effective control and perhaps safest relative to avoiding the sap focuses on properly timed herbicide applications.  Non-selective herbicides, such as glyphosate (e.g. Roundup) or pelargonic acid (e.g. Scythe), applied now can eliminate the first season rosette stage and the second season flowering stage, before seeds are produced.  Selective herbicides, such as triclopyr (e.g. Triclopyr 4, Ortho Poison Ivy and Trough Brush Killer) or clorpyralid (e.g.Transline), may also be applied now, but are generally more effective once plants start initiating the flower stalks.  Of course, as always, you must read and follow the label directions when using any herbicide to maximize safety and product efficacy.