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 Amy Stone
Published on March 27, 2019
As temperatures warm, people are outside enjoying the almost, spring-like weather. There are still a few waiting for even warmer temperatures to arrive and stick around for more than a day – you know who you are. As everyone migrates outdoors as temperatures rise, the chances of an insect encounter will be pretty high. At the first encounter, many people may have an urge to “eliminate” the six legged species. Some may have thoughts of a quick step and smush, others may want to reach for a bottle to abolish the “pest.” It is important to take a step back – not necessarily to avoid the insect, but to identify it first and then act accordingly. Many times the recommended action will be to do nothing at all. Many insects that we encounter are beneficial and have important jobs to accomplish in what is typically a rather short life-span. Jobs that would be hindered if we stop their existence simply because we don’t like insects, we have a fear of insects, or just don’t care.
Earlier this week, a homeowner had an insect encounter as they were walking around the outside of their home. Instead of going into kill-mode, this homeowner collected the insect and brought it to their local Extension office for identification. Photos were taken of this rather larger black insect and the images began making the rounds being shared among Extension professionals. The insect was identified as the big-headed ground beetle, aka the pedunculate ground beetle (Scarites subterraneus). This insect is a predator and great for the garden.
This alert really serves three purposes that we would like to share with the readers:
If you weren’t familiar with the big-headed ground beetle, you are now. These ground beetles are very common in cultivated soils. They are about 1/2 to 3/4 of an inch in length, have a flattened appearance, and have front legs designed for digging.
Photo Credit: Amy Stone, OSU Extension – Lucas County; Good Garden Bugs by Author Mary Gardiner
If you come across an insect that you aren’t familiar with, don’t assume the worst, although there are some bad insects in the bunch. With care, collect the insect or take photos of the insect and do some research. Photos should be clear and also illustrate a size comparison whenever possible. Bad photos can lead to a bad identification or no identification at all. Blurry images can often make it impossible to identification an insect with 100% certainty. Engage your local Extension office, reach out to members of our BYGL writing team, connect with a green industry professional such as a certified arborist, landscaper or garden center expert, or take a look in books or on the internet.
And finally, we mention the internet. Just a reminder that not everything you read on the internet is true. While seeking information, you will also have to search out the truth and sort through lots of other information. Sites that end in “edu” are a great place to start.
Enjoy the warmer temperatures and expect an insect encounter while you are gardening, landscaping or just enjoying nature this spring.
Authors Amy Stone
Published on March 27, 2019
Earlier this month, Joe Boggs authored a BYGL Alert entitled, Ash Breakage: the Hazard Continues (March 19, 2019). To follow-up with this topic, we wanted to alert you to an upcoming webinar from EAB University called Dead Ash Dangers and Considerations for Risk and Removal.
The online presentation will be held on April 2, 2019 at 11:00 am (EST).
To register click on this link: https://msu.zoom.us/webinar/register/WN_QlthhbABToCfA3b36EHUWA
All EABU webinars are free and tuning into many of the live webinars can earn you continuing education credits. If you can’t watch it live, but are still interested in the topic – no problem! All webinars are recorded and posted online after the session. Check out the list of previously recorded sessions on the regionally EAB website at: http://www.emeraldashborer.info/
There will be one more live EABU spring session following the April 2 program. On April 16, 2019 at 11 am (EST), Nate Siegert with the US Forest Service will be talking about Emerald Ash Borer: Perspective from a Recently Infested State.
While EAB is what some called old news in Ohio, there are folks who want to stay updated on its progress. The EAB invasion has advanced across the Northeast over the last decade, with the first detections occurring in western New York in 2009 and the most recent detections in Maine in 2018. Presently, infestation across the region may be characterized as mix of generally infested areas, newly infested locations, and expanding satellite infestations, with many areas yet to be invaded. The spatial and temporal dynamics of the EAB invasion along the leading edge from New York to Maine will be discussed, including a review of selected management activities, updates on recent changes, and future direction of management and regulatory work in light of reduced funding and potential federal deregulation.
Stay updated on EAB and other invasive species through EABU!
Emerald Ash Borer University
Regional Emerald Ash Borer Website
Authors Amy Stone
Published on March 27, 2019
Gardeners are always looking for signs of spring. Although the calendar tells us it is officially spring, Mother-Nature can sometimes send mixed messages.
The brightly colored yellow flowers of the winter aconite (Eranthis hyemalis) covering the ground might be just the sign that spring has arrived – at least we hope. Winter aconites are a bulb that will naturalize, creating a blanket of yellow flowers for all to enjoy. In fact, the bees were busy visiting one flower after another while I was out enjoying a walk around the Toledo Botanical Garden.
Photo Credit: Amy Stone, OSU Extension – Lucas County
The winter aconite is in the family Ranunculaceae. The plant prefers full sun to partial shade. One of my favorite sites to enjoy a naturalized stand is in a woodland garden that later this year will be dominated by shade produced by the mature trees, but in late winter and early spring it is just the perfect setting for these bulbs to show their horticultural-stuff.
It is also thought that the winter aconites can be grown among black walnut trees and that deer don’t particularly care for them. I have even enjoyed them peaking up through a blanket of snow. Thank goodness that wasn’t the case when I captured the images earlier this week.
If you are establishing this plant in the landscape, you will want to plant tubers 2-3″ deep and 3″ apart in late summer to early fall. It is recommended that you soak tubers overnight before planting. Once established, you may notice some self-seeding and naturalizing over time in optimum growing conditions. They tend not to like being disturbed or moved frequently. It is best to identify the location and let them live out their lives in that spot.
The plant is native to Europe. The genus (Eranthis) comes from the Greek words er meaning spring and anthos meaning a flower for its very early flowering. The specific epithet (hyemalis) means of winter or winter blooming.
Winter aconites can make a great addition to the front of perennial or shrub borders, in among the rocks in a rock garden, alongside pathways or walkways, and will also do well in containers. They are eye catching in masses and large numbers. Just remember that because they bloom so early in the season, don’t tuck them away in a far corner of the garden, but rather plant them somewhere they can be appreciated and enjoyed even if it is cold outside.
Missouri Botanical Garden, Plant FInder
Authors Joe Boggs
Published on March 26, 2019
Poison hemlock (Conium maculatum) is a non-native biennial weed that spends its first year as a low-growing 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 and are prolific seed producers.
Despite its common name, poison hemlock is not a tree; it is a member of the carrot family, Apiaceae (formerly Umbelliferae). It shares floral characteristics with other non-native members of the carrot family such as Queen Anne’s lace (Daucus carota) and the wild parsnip (Pastinaca sativa) which is notorious for producing sap that causes skin blisters.
All stages of the poison hemlock plant have bluish-green leaves that are 3-4 times pinnately compound. 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.
Poison hemlock is one of the deadliest plants in North America. This invasive plant was imported as an ornamental in the late 1800s from Europe, West Asia, and North Africa. The plant contains highly toxic piperidine alkaloid compounds, including coniine and gamma-coniceine, which cause respiratory failure and death in mammals.
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 accidentally ingested while handling food.
The roots are more toxic than the leaves and stems; however, all parts of the plant including the seeds should be considered dangerous. Unfortunately, this dangerously toxic plant is becoming more common throughout Ohio including growth in landscape plantings where the close proximity to people increases poisoning risks.
While poison hemlock can be partially managed by mowing and tilling, the most effective control approach involves properly timed applications of selective or non-selective post-emergent herbicides including glyphosate (e.g. Roundup). Each plant produces hundreds of seeds, so applications of herbicides made now will control both the first season rosette stage and the second season flowering stage before seeds are produced.
Authors Joe Boggs
Published on March 26, 2019
White Pine Weevil (Pissodes strobi) females spend the winter out of sight cooling their six heels in the duff beneath their pine or spruce targets. As temperatures warm in the spring, they climb their hosts to feed and lay eggs in the terminals. Sap oozing from small holes in the terminals is a calling card of this weevil.
Females begin to emerge from their winter abodes when the accumulated Growing Degree Days (GDD) reach 84. This roughly coincides with the full bloom of northern lights forsythia (Forsythia x intermedia), speckled alder (Alnus incana), and cornelian cherry dogwood (Cornus mas). We have not yet reached the magic GDD number of 84 in southern Ohio; however, cornelian cherry dogwood bloom buds are beginning to show color meaning the weevils may soon be stirring.
This native weevil has a wide conifer host range that includes Scotch, jack, red, pitch, and eastern white pines as well as Douglas-fir and all spruces. Indeed, the weevil’s love of spruce is exemplified by its alternate common name, Engelmann Spruce Weevil, or simply Spruce Weevil. White pine weevil is not just found in Ohio; it ranges from the east coast west into the Rockies.
The females use their chewing mouthparts located at the tip of their long snout (rostrum) to chew small holes through the bark to feed on the sugar and nutrient-rich phloem. Eventually, they will turn around and deposit an egg in some of these holes.
The resulting white, legless, slightly curved, grub-like larvae tunnel downward side-by-side just beneath the bark feeding on the phloem. Pupation later this season is marked by the construction of so-called “chip cocoons” by the larvae prior to entering the pupal stage.
Infested leaders wilt, turn brown, and die. Dead leaders occurring in mid-summer which sometimes have a curved “shepherd’s crook” appearance is another calling card of this weevil. New adults emerge from the infested terminals late in the season to feed and mate. Females of this second generation then crawl to the duff to spend the winter in preparation for sneaking up on us next spring.
The weevils are capable of killing small trees less than 3′ in height, but it does not kill large trees. However, years of successive damage to terminal leaders will eventually create “cabbage trees” which are short, squat trees with multiple terminal leaders in landscapes and woodlots. Of course, loss of the leaders presents a serious production problem in nurseries and Christmas tree plantations.
There are three effective suppression tools for reducing damage. The first is the application of a “borer spray” to the terminals to kill the females before they lay eggs. Effective products include those based on the active ingredients bifenthrin (e.g. Onyx), permethrin (e.g. Astro), or cyfluthrin (e.g. Tempo). A second application may be required depending on spring weather conditions and product label recommendations.
If female weevils make it through the terminal insecticide applications, the second suppression tool is to remove and destroy infested terminals prior to the emergence of the next generation of adults later this season. This will reduce the localized weevil population which is particularly effective where there are few conifer hosts growing in nearby forests or landscapes. I’ll post a complete “how to” on this method later this season.
The third weevil management strategy is to make preventative systemic insecticide applications in the fall that target the weevils as they feed on the phloem the following spring. The systemics will also kill early instar larvae as they begin tunneling in the phloem but before they produce serious damage. Systemics such as imidacloprid (e.g. Merit, Nuprid 1.6F, etc.) may be applied using soil drench or soil injection applications. This preventative control measure should be reserved for landscapes, nurseries, or Christmas tree plantations that have a history of significant white pine weevil activity.
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.