Wayne County Scouting Notes from the week of June 21-June 27

Vegetable Pests

            Potato Leaf Hoppers are feeding on potato and green beans. They will also cause damage to eggplant and other crops as well. Their feeding causes what is known as “hopper burn” around the leaf edges and if left untreated, the feeding will eventually cause the leaves to turn brown and begin to die back.

Cucumber Beetles are high in numbers right now. Cucumber Beetles vector the Bacterial Wilt disease so early season control of the beetles is vital to the long-term health of the plant. Also note that as your plants are blooming, the beetles may be in the blossoms. In small enough numbers, this is okay, but they can also damage the fruit from feeding on the blossom. Consider the pollinators when planning out treatment options for cucumber beetle.

European Corn Borer is now doing damage in tasseling corn. The small ECB larva feed in the tassels as well as the ears. It is important to thoroughly inspect the plants as you are scouting, especially with early season corn as their damage will not always be detected in the tassel like in later planted sweet corn. An ECB trap in Wayne County had 9 moths in the trap this week.

Onion thrips populations have really trended upwards. Damage from thrips occurs primarily in the center of the plant where the new growth is emerging. Heavy feeding can lead to reduced bulb size or even plant death. The thrips damage can also open the plant up to purple blotch which is able to infect the plant via the wounds created by the thrips feeding. Click here to see photos of thrips and the damage they cause.

Colorado Potato Beetle are still feeding on eggplant and potatoes. Although their numbers are not as high where there has been several treatments, their populations can quickly get out of hand.

Vegetable Diseases

            Downy Mildew has been confirmed in south west Michigan. Considering the proximity to Ohio, it has been recommended that cucumber growers begin a downy mildew fungicide program immediately. Read more from Sally Miller’s lab.

Some of the field peppers I am scouting showed signs of damping off. Damping off is caused by soil borne fungi such as Rhizoctonia, Pythium, Fusarium and Phytophthora.

Powdery mildew is starting to show up on cucurbit crops around the state. I have not yet had any cases in Wayne County, but this disease should be watched for closely.

Fruit Pests

Spotted Wing Drosophila are starting to be found in Wayne County and surrounding areas. As more small fruits come into season, expect the number of SWD to increase rapidly. “Monitoring and Managing Spotted Wing Drosophila in Fruit Crops” 

Codling Moth and Oriental Fruit Moth traps had an increase in numbers but nothing above threshold levels.

Keep an eye out for aphids in orchard crops. We are getting into the time of year where aphid populations begin to increase and can do so rapidly. Leafhoppers are another pest to be on the look out for.

Fruit Diseases

            It is the right time to consider looking at managing summer diseases such as flyspeck, sooty blotch, and fruit rots. This note can go for peaches as well with diseases such as brown rot and scab.

Another note on apples, although not a disease, the effect of freeze/cold damage can appear unsightly and may be confused for a disease. This scabby looking ring or spots on the fruit are known as “frost rings”. This is a result of the tissues being damaged in cold or freezing temperatures. Rich Marini from Penn State notes “Sometimes frost during bloom may not kill a flower or small fruit, but may injure the skin tissues and cause a ring of russet around the fruit and these are referred to as frost rings.” Read more here about apple skin disorders.

Grapes are now around the “shatter” stage where the unfertilized berries fall off the clusters. It is important to be considering proactive treatments for grape downy mildew especially if you have a variety of grapes that are susceptible to downy mildew.

Factors Influencing Measures of °Brix (Soluble Solids), an Indicator of Potential Crop Quality

°Brix readings continue to interest and confuse farmers and others. Collecting a reading is far easier than making decisions based on it. In fact, it takes just moments to obtain a °Brix (soluble solids) reading in the field, packing shed, or elsewhere; the major steps include collecting a small drop of plant sap or juice and placing it on a properly maintained and used refractometer, a handheld instrument that fits easily in your pocket. A reading typically can be in hand in less than two minutes. However, making proper use of the °Brix value requires effort and experience for reasons outlined below.

The sugar sucrose is perhaps the most prevalent soluble solid in plant juice. Therefore, many vegetable-based °Brix (refractometer) readings are set primarily by the number of sucrose molecules in the sap or juice used as the sample (unless the sample is contaminated). Within a crop, these sucrose levels are, in turn, influenced by:
1. Variety;
2. Plant population/density;
3. Irrigation or soil moisture status;
4. Nutrient management or soil fertility status;
5. The plant part sampled (e.g., root, stem, leaf, fruit) and exact portion of it;
6. The age (maturity, position) of the plant part sampled;
7. Time of day of sampling;
8. Temperature and light conditions;
9. Post-harvest conditions; and
10. Other factors.

Not surprisingly, experienced refractometer users understand that it is essential:

1. To use a standardized, consistent approach involving sampling the same plant part (and portion) at the same development stage at the same time of day, etc. That way, comparisons based on other factors are more reliable.
2. To obtain and record many values (the process is nearly free minus small initial investments). Much like measures of blood sugar, cholesterol, heart rate, etc, the worth of one °Brix reading in decision-making is often based on comparing it to readings collected previously and the conditions under which they were collected.

We have measured °Brix levels in vegetable crops grown on Ohio farms and at OSU research stations for nearly twenty years using protocols explained in fact sheets at https://u.osu.edu/vegprolab/research-areas/product-quality-2/ and taking factors listed above into account. The data below were collected in July-November 2011 by Dr. Natalie Bumgarner (then a graduate student at The OSU and now with Cooperative Extension at the University of Tennessee). Note the variation within and across crops.

Contact Matt Kleinhenz (330.263.3810; kleinhenz.1@osu.edu) for more information.

Insect observations

A few Japanese beetles were sighted today on a peach tree in Columbus. Late June is the usual time that this pest begins to emerge. Beware that large congregations might be seen on their preferred crops over the next few weeks. Japanese beetle is a pest of sweet corn, snap beans, raspberries, grapes, plum, peaches, blueberries, and hops as well as ornamental plants such as roses and linden trees and sassafras, and weeds such as smartweed. This pest can be more readily controlled by insecticides if the spray is made when the congregations are just beginning to form. Insecticides that are very effective for control of Japanese beetle are old ones: carbaryl (Sevin) and pyrethrins plus PBO (EverGreen Pro).

True armyworm is active in corn fields and grassy areas. We previously reported a large surge in the number of armyworm moths caught in our blacklight trap in Columbus between 5/14 and 5/18, with a record of 210 moths in one night on 5/14. We have been seeing increased numbers of moths during the past week, including today when there were 96 armyworm moths in the trap. There have been reports of armyworm larvae being found in field corn fields around Ohio. Daily counts of armyworm and several other common moths in blacklight traps are posted here:  https://docs.google.com/spreadsheets/d/10gh3rHahdxLKkXQapGyEPxWsjHYRmgsezOoFHnwtyEo/edit#gid=1114468121

Squash vine borer is now active, and abundant at our research farm in Columbus. Its adult is a day-flying moth that will be laying eggs on zucchini and other summer squash, winter squash (except butternut), pumpkins, and gourds over the next few weeks. It generally is a severe problem in home gardens and in small plantings, but less severe in large fields. Insecticide can be effective if directed to the base of the main stem before eggs have hatched, usually at least 2 or 3 sprays at 10-day intervals. Insecticides used for its control are pyrethroids such as Asana (esfenvalerate), Pounce (permethrin), Warrior (lambda-cyhalothrin), MustangMaxx (zeta-cypermethrin), or Brigade (bifenthrin); it is usually not well controlled by Sevin (carbaryl). We have found that EverGreen Pro (pyrethrins plus PBO) is effective although squash vine borer is not listed as a target pest on its label. This year we have a field trial in progress to evaluate the non-chemical tactic of a border trap crop of unharvested zucchini.

Corn earworm has been active for the past few weeks but at low numbers, which is typical of this pest in Ohio in early summer in most years. We have not seen the surge in moth activity like we did last year in late May and early June. A pheromone trap is highly effective at detecting the presence of the moth. Farms with early planted sweet corn should have their trap out as soon as tassels are emerging. Information on using traps is available here: https://cpb-us-w2.wpmucdn.com/u.osu.edu/dist/1/8311/files/2014/12/CornTrapInstructions2009-u47rp3.pdf   Information on buying traps to monitor corn earworm is here:  https://cpb-us-w2.wpmucdn.com/u.osu.edu/dist/1/8311/files/2019/07/TrapSpecsAndSources2019.pdf . Trap counts from several Ohio locations are posted here: https://docs.google.com/spreadsheets/d/10gh3rHahdxLKkXQapGyEPxWsjHYRmgsezOoFHnwtyEo/edit#gid=0

Potato leafhopper is active and being reported from beans, potatoes, apples, and hops. The adults and nymphs of this pest are found on leaf undersides where they suck sap. Their feeding results in yellowing then browning along the edge of leaves, a symptom known as ‘hopperburn’. Leafhoppers can be controlled by sprays of a neonicotinoid such as Admire (imidacloprid) or Assail (acetamiprid), or a pyrethroid such as Pounce (permethrin), Warrior (lambda-cyhalothrin), MustangMaxx (zeta-cypermethrin), Brigade (bifenthrin), or by dimethoate.

Brown marmorated stink bug is active now. Our traps are catching only adult stink bugs so far, but a few young nymphs have been seen on host plants. This year we are continuing our investigations of the samurai wasp, which is a tiny parasitoid that specializes in killing the eggs of this stink bug. We have a colony of the samurai wasp at OSU, and we have made releases of it at ten Ohio fruit farms, in comparison with 10 Ohio fruit farms where we did not make a release. We are currently sampling those 20 farms to see if the samurai wasp has become established.

Spotted lanternfly: This invasive exotic pest has NOT yet been found in Ohio, but many people are on the lookout for it, especially in eastern Ohio, because it has been spreading from its initial infestation in eastern Pennsylvania. Its favorite host plant is the tree of heaven but it can cause damage to grapes, hops, blueberries, and other fruit crops, mostly in late summer.

-Celeste Welty, Extension Entomologist

Managing Cucurbit Powdery Mildew

Powdery mildew colonies on the lower leaf surface.

Powdery mildew has begun to appear on pumpkins and other cucurbits in Ohio. Signs of infection are small circular powdery growths on either side of the leaf. These spots enlarge and can eventually cover most of the leaf surface and kill the leaves. Stems and leaf petioles are also susceptible, but the disease is not observed on fruit. In pumpkins, powdery mildew may also attack the “handles”, which can be further damaged by secondary pathogens. It is time to start scouting cucurbits for powdery mildew.

Powdery mildew is managed using disease-resistant varieties and fungicides. Pumpkin and squash varieties vary in resistance to powdery mildew; in general, the more susceptible the variety, the more fungicide needed. The choice of fungicide is important because insensitivity to overused fungicides is common. It is critical that a fungicide resistance management program is followed. Alternate fungicides in different FRAC (Fungicide Resistance Action Committee) groups, indicating different modes of action against the fungus. Fungicide applications should begin when the disease first appears and incidence is low. Fungicides that are labeled for use against cucurbit powdery mildew can be found in the Midwest Vegetable Production Guide for Commercial Growers; product ratings and FRAC codes are on page 129. Vivando (U8), Quintec and fungicides containing FRAC 3 group active ingredients (Aprovia Top, Inspire Super, Luna Experience, Procure, Rally) have fewer reported failures due to fungicide resistance than others listed in the Guide and are recommended for Ohio (see table below – click too enlarge). These products should be tank-mixed with a protectant fungicide such as chlorothalanil (Bravo and similar products), copper- or sulfur-based products.

Our evaluations of efficacy of powdery mildew fungicides in Ohio in 2018 indicated that Inspire Super, Procure, Rally, Aprovia Top and Quintec provided very good control of powdery mildew on pumpkins in three locations.  Bravo Weather Stik and Fontelis provided moderate control and Pristine, Merivon Xemium and Torino provided poor control.

A list of products for powdery mildew management in organic cucurbits prepared by Dr. Meg McGrath of Cornell University can be found here.

Spotted Wing Drosophila Back in Action

As expected, Covid-19 has slowed many things in Ohio but one of them is NOT spotted wing Drosophila! Ohio State University Extension, the Department of Entomology, and the IPM Program have again set up a statewide SWD monitoring program for this pest in 11 counties. The Scentry lure baited traps were deployed the week of June 15, and the first trap checks for positive male or female SWD occurred this week.

SWD trap.

As of Friday June 26, three counties reported positive identifications of SWD; Champaign, Greene and Franklin. Other counties are likely positive but have not been reported as of yet. Recall that the threshold for this pest is one fly, which triggers an insecticide spray program if the berries are ripening or ripe through harvest. Details on spray programs can be found here: https://cpb-us-w2.wpmucdn.com/u.osu.edu/dist/1/8311/files/2019/11/SWD_Ohio_handoutV19.pdf

If you have ripe berries and have not been spraying, your chance of infestation is still likely low but you may consider looking for larvae in the fruit using a salt water test. The process is fairly simple and can be found here: https://youtu.be/MtMXHxqcSVs.  While on the OSU IPM YouTube site look around at our other SWD videos if interested in identification, trap set up and deployment or exclusion netting.

 

Wayne County IPM Scouting Notes from June 15 – June 19

Wayne County IPM Notes

(From the Week of June 15 – June 19)

Frank Becker, IPM Program Coordinator

OSU Extension Wayne County

Vegetable Pests

Japanese Beetle on corn, F. Becker photo

This week I began seeing Japanese Beetles, specifically in sweet corn. These beetles are generalist feeders and will do damage to most any crop. Keep an eye out for the beetles and the defoliation that they can cause. More Info

Flea Beetles are doing damage to a lot of younger transplants. Flea Beetles will utilize weeds as host plants. Keeping your fields free from weeds will help to reduce the populations of flea beetles.

Cucumber Beetles are high in numbers right now. Cucumber Beetles vector the Bacterial Wilt disease so early season control of the beetles is vital to the long-term health of the plant. Also note that as your plants are blooming, the beetles may be in the blossoms. In small enough numbers, they are not detrimental, but they can also damage the fruit from feeding on the blossom and interfering with pollination. Consider the pollinators when planning out treatment options for cucumber beetle.

European Corn Borer moths are out. A trap this week in Wayne County picked up 14 moths. ECB will do damage to both peppers and sweet corn.

Onions are at a point where thrips populations could begin to increase. Consistent rains and small plants had kept the thrips population down, but with onions increasing in size and putting on more leaves, this will be a pest to watch in the next few weeks.

The Imported Cabbageworm larvae, among other worm pests of brassicas, are feeding on cole crops and leafy greens such as kale. Severe foliar feeding could stunt the plant growth or significantly reduce yield.

Vegetable Diseases

            Timber rot is still being found, mostly in high tunnel tomatoes. Botrytis is still being seen too, as is blossom end rot. To manage blossom end rot, it is important to limit moisture stress on a plant, from either too much or not enough moisture. Being consistent in watering and monitoring soil moisture conditions will help to prevent exposing the plant to moisture stress. Proper moisture will also provide conducive conditions for adequate nutrient uptake, given that the nutrients are present at appropriate levels in the soil.

Botrytis is also being seen in onions. This disease is primarily affecting the foliage but can impact the integrity of the bulb if left uncontrolled. Find out more about management of onion diseases here: Growing Onions

Some of the field peppers I am scouting showed signs of damping off. Damping off is caused by soil borne fungi such as Rhizoctonia, Pythium, Fusarium and Phytophthora.

Fruit Pests

Japanese Beetles, left untreated, feeding on young apples, F. Becker photo

With finding Japanese Beetles this week, I would encourage fruit growers to keep a close eye on their trees and small fruit plants. Grapes especially can be a target of the Japanese Beetle and can be defoliated very rapidly. This kind of damage can be detrimental to the yield of the crop. Japanese Beetles will also do damage to the fruit, as seen in the photo to the right, taken in 2019.

SWD traps are out and we will start getting an idea of population numbers within the next week.

Codling Moth and Oriental Fruit Moth traps counts were low but starting to tick up. This week will be an important week in determining the next generation of moths. More on Codling Moth management and additional information from Celeste Welty: Codling Moth

Fruit Diseases

            Now is the time to be managing early season diseases in apples. Scab, rust and powdery mildew are the three main diseases of concern at this point in the season. It may also be appropriate to start considering managing summer diseases such as flyspeck, sooty blotch, and fruit rots.

Strawberry leaf diseases may appear unsightly right now, however, now is not the time to be managing these leaf diseases. Once harvest is done and during patch renovation it is recommended that you address these concerns, either with a fungicide or with resistant plant varieties. This is also a critical time to be watching for fruit rots such as Botrytis.

 

Cucumber Downy Mildew Confirmed in Michigan

Cucumber downy mildew was found today in Berrien County in southwest Michigan.  This is the first report of cucurbit downy mildew this year in the Great Lakes region. The pathogen was detected in spore traps in Berrien County June 8, 10, and 13, and in Muskegon County on June 8. Dr. Mary Hausbeck has provided details of the outbreak and a link to the spore trap data here.

This is relatively early for cucumber downy mildew in Michigan and Ohio – we often see it around the 4th of July and last year it appeared weeks later. Humid, rainy, cool to warm weather favors this disease. It is likely that downy mildew will be in Ohio soon, especially the northern counties, if it is not already here. Cucumber growers in the northern third of the state should begin a downy mildew fungicide program immediately.  Dr. Hausbeck recommends a rotation of the following fungicides tanked mixed with chlorothalanil or mancozeb: Ranman, Elumin, Zampro, Previcur Flex, or Orondis Opti (no need to tank mix Orondis Opti since it is a premix with chlorothalanil). Make sure to check the labels for use restrictions and preharvest intervals (PHIs).

The Michigan recommendations are based on 2019 field evaluations of these fungicides.  Our Ohio bioassay evaluations in 2019 had similar results, although we did not test Previcur Flex.

You can follow reporting of cucurbit downy mildew outbreaks in the US on the CDM ipmPIPE website.  This website was revamped this year and if you want to receive alerts of downy mildew outbreaks you will need to sign up, even if you had signed up on the previous website.

If you think you have downy mildew in cucumbers or other cucurbits on your farm or in your home garden, you can send samples to the OSU Vegetable Pathology Lab for a free diagnosis.

Septoria Leaf Spot of Tomatoes is Here

Septoria leaf spot has been found in Ohio this week, perhaps not surprisingly due to frequent heavy rains in many areas. Dr. Francesca Rotondo, vegetable disease diagnostician and research associate in the OSU Vegetable Pathology Lab, texted me this photo taken today in her home garden. This excellent photo is diagnostic for Septoria leaf spot: round tan to brown spots on the leaves and leaf yellowing. In the more mature spots, margins are dark brown and small round black dots can be seen in them through a hand lens or the lens of your smartphone camera. The tiny black dots are called pycnidia, the fruiting bodies of this fungus. Pycnidia are flask-shaped with a small hole at the top, and partially submerged in leaf tissue. Pycnidia contain large numbers of spores held in a gelatinous matrix; when humidity is high or free water is on the leaf surface, the spores ooze out of the pycnidia like toothpaste being squeezed out of a tube. The spores are dispersed by rain or irrigation water to other leaves on the same plant and to other nearby tomato plants.

Septoria lycopersici is seedborne and also survives at least 1-2 years in soil. Septoria leaf spot is favored by moderate temperatures, high humidity and rain or overhead irrigation. While Septoria does not cause spots on tomato fruit, it can rapidly defoliate the plant. If this happens early the plant is likely to die. Later on, defoliation leads to small fruit, poor ripening and problems with sunscald. Even large, previously healthy, vigorous plants can be completely defoliated.

Commercial growers can manage Septoria leaf spot by including a strobilurin fungicide such as Quadris or Cabrio in a fungicide program that also includes a protectant such as chlorothalanil or mancozeb. A list of labeled fungicides to manage Septoria leaf spot can be found in the Midwest Vegetable Production Guide for Commercial Growers. Cultural practices to minimize Septoria leaf spot should be undertaken, including crop rotation of 3 years or more, planting tomatoes on raised beds, using adequate spacing, using drip irrigation, pruning foliage to allow good air movement through the canopy, and removing diseased plants from the field. Septoria leaf spot is rarely a problem in high tunnels, greenhouses and other structures that protect plants from rain.

Organic growers need to follow the cultural practices described above and may consider growing tomatoes in protected culture. Copper-based fungicides formulated for organic production can suppress disease development if applied soon after initial symptoms appear.

Home gardeners should adopt the cultural practices described above and should also remove and destroy leaves with symptoms. This is really only effective when symptoms first appear. Always avoid the foliage when watering plants. Fungicides containing chlorothalanil or copper can be applied to slow disease spread.

Wayne County Scouting Notes, June 8 – June 12

Wayne County IPM Notes

(From the Week of June 8 – June 12)

Frank Becker, OSU Extension Wayne County

Vegetable Pests

Young Colorado Potato Beetle larva (F. Becker photo)

The Colorado Potato Beetle is still feeding heavily, especially on potato. The larvae are out in large numbers and many egg clusters are hatching or will soon be. They are most effectively controlled in the larval stage. It is best to coordinate insecticide applications in line with when the egg masses are hatching, and young larva are starting to feed on the foliage.

Flea Beetles are still prevalent and doing damage. Flea Beetles will also utilize weeds as host plants. Keeping your fields free from weeds will help to reduce the populations of flea beetles.

Cucumber Beetles are out in force right now. For growers who use a seed treatment on cucurbit crops, keep in mind that the treatment is typically effective up to the 2-leaf stage, at which point the efficacy starts to decline. Cucumber Beetles vector the Bacterial Wilt disease so early season control of the beetles is vital to the long-term health of the plant.

In sweet corn, cut worm damage has started popping up along with some more significant European corn borer damage.

Onions are at a point where thrips populations could begin to increase. Consistent rains and small plants had kept the thrips population down, but with some drier weather in the forecast and onions increasing in size and putting on more leaves, this will be a pest to keep an eye on.

Imported Cabbage Worm Larva (F. Becker photo)

The Imported Cabbageworm larvae, among other worm pests of brassicas, are feeding on cole crops and leafy greens such as kale. Severe foliar feeding could stunt the plant growth or significantly reduce yield.

Vegetable Diseases

Timber Rot on a high tunnel tomato (F. Becker photo)

Timber rot of tomato is being found, especially in high tunnel tomatoes. This disease will take down a plant very rapidly. The survival structure, called a sclerotia, can survive in the soil for several years. It is important to allow for good airflow to avoid excess moisture in the tunnel. Additionally, it is recommended that if you are pruning to sanitize the tools between each cut. Diseased plants may also be removed and disposed of to prevent further spread of the pathogen.  Find more details about timber rot and management options in this article by Sally Miller: https://u.osu.edu/miller.769/2016/06/22/white-moldtimber-rot-management-in-tomato-high-tunnels/

Botrytis is still being seen, as is blossom end rot. To manage blossom end rot, it is important to limit moisture stress on a plant, from either too much or not enough moisture. Being consistent in watering and monitoring soil moisture conditions will help to prevent exposing the plant to moisture stress. Proper moisture will also provide conducive conditions for adequate nutrient uptake, given that the nutrients are present at appropriate levels in the soil.

 

Fruit Pests

Strawberry producers typically are facing several insect pests this time of year. One of these pests is the eastern flower thrips. This small insect feeds on and damages the strawberry blossom. As the berry begins to develop, this damage results in cat-facing on the berry or a russeting/bronzed appearance. When you notice these symptoms on the developing berry, the damage has already been done and there are no treatment options. To look for thrips in the blossoms, take a white piece of paper or a plate and shake the blossoms onto the plate and watch for any small, slender yellow thrips to be moving around. Once you have reached 2 or more thrips per blossom, you should move forward with a treatment. Consider the pollinators before applying an insecticide, considering the target of your application is primarily associated with the blossoms. Preventative sprays can also be used in successive plantings. See more on Thrips in this post by Celeste Welty: Beware of thrips on strawberries

Another pest of strawberries and small fruits is the spotted wing Drosophila. The SWD is a small fruit fly that can lay its eggs in ripening fruit while it is still on the plant. As you are picking, do not discard unwanted fruit on the ground right next to the plant. The rotting fruit on the ground will attract SWD. Instead bring a bucket to discard unwanted fruit in and either bury it a foot or so deep in soil or seal the fruit in a clear plastic bag exposed to the sun for about a week to kill any larvae. If culls are discarded in the trash or compost pile, they might attract SWD flies and allow for more generations to be produced. This is also the time to put traps out in your bramble and blueberry patch but if you have June bearing strawberries, they likely won’t be affected by this pest. More details about how to set up traps can be in the  OSU IPM YouTube page under the SWD playlist at https://www.youtube.com/channel/UCzcWaLH3mx7HUKh4OF7bYPA and on Celeste Welty’s page here: https://u.osu.edu/pestmanagement/

Codling Moth and Oriental Fruit Moth traps are showing low numbers right now.

Fruit Diseases

            Now is the time to be managing early season diseases in apples. Scab, rust and powdery mildew are the three main diseases of concern at this point in the season. It may also be appropriate to consider looking at managing summer diseases such as flyspeck, sooty blotch, and fruit rots.

Strawberry leaf diseases may appear unsightly right now, however, now is not the time to be managing these leaf diseases. Once harvest is done and during patch renovation it is recommended that you address these concerns, either with a fungicide or with resistant plant varieties. This is also a critical time to be watching for fruit rots such as Botrytis.

Grapes are currently either at pre-bloom or blooming. This stage is the most critical stage of development for controlling diseases. Fungicide applications for black rot, powdery mildew and downy mildew are highly recommended during this time. See more details about grape black rot here.

 

What’s new with herbicides?

What’s new with herbicides?

2020 brings new registrations of use to the vegetable producer. Weed control in vegetables usually requires a careful integration of tillage, herbicides, cultivation and mulches. No single herbicide will control all weeds for the entire season. The following summarizes guidelines for use on crops that extracted from product labels, the final authority. If you have further questions please contact me, or your local agricultural educator.

Pumpkin, Squash & Tomato. Reflex Herbicide (EPA Reg. No. 100-993). (Ohio Section 24 OH0993019AA0619 OH-200002; for use only in Ohio). Pumpkin, squash and tomato varieties may vary in their tolerance to Reflex herbicide. Be certain of crop tolerance before using Reflex on a new variety. Butternut squash is very sensitive to Reflex. Cold and wet soils during pumpkin and squash germination and maturity may result in delayed maturity and/ or yield. Heavy rain shortly after transplanting may also result in delayed maturity and/ or yield. Reflex persists in the soil for a considerable time providing weed control; however, this characteristic also means that several crops may be damaged if grown in close rotations following use of Reflex.

• Direct Seeded Pumpkin, Summer and Winter Squash (32 day PHI). Apply Reflex at ½ – 1 pint/A broadcast preemergence after seeding and before the crop emerges. If rainfall does not occur before crop emergence, an overhead irrigation will activate the herbicide and reduce the potential for crop injury from splashing soil onto crop leaves.
• Transplant Pumpkin, Summer and Winter Squash(32 day PHI). Apply Reflex at ½ – 1 pint/A as a pre-transplant, non-incorporated preemergence broadcast application up to 7 days before transplanting. Minimize further soil disturbance during transplanting or weed control may be compromised, and avoid any practice that may concentrate the herbicide around the transplant plug.
• Transplant Tomato on bare ground (70 day PHI). Apply Reflex at 1 pint/A as a pre-transplant, non-incorporated preemergence broadcast application up to 7 days before transplanting. Minimize further soil disturbance during transplanting or weed control may be compromised, and avoid any practice that may concentrate the herbicide around the transplant plug.
• Transplant Tomato in plastic mulch (70 day PHI). Apply Reflex at 1 pint/A as a pre-transplant, non-incorporated preemergence broadcast application after the final raised bed has been formed but before mulch has been laid. Do not disturb the soil after laying the mulch.

Onion (bulb) & Leeks (60 day PHI). Zidua Herbicide (EPA Supplemental Label, Registration No. 7969-338). Apply postemergence, after seeded onion emergence or after transplanting leeks but before broadleaf weeds have emerged. Zidua does not control emerged weeds. Apply 1.3 to 1.7 ozs/A to onion and leek in medium or fine textured soils. Apply 1.7 ozs/A to onion or leak in muck soils with 20% or more organic matter. Crop-stage should be 2-6 true leaves. Do not apply to coarse textured soils.

Asparagus & Rhubarb. QuinStar 4L Herbicide (EPA Reg’n No. 42750-169). For control of emerged field bindweed and hedge bindweed, apply Quinstar in the fall but before frost to bindweeds that are actively growing. Apply Quinstar at 12.6 ozs/ Acre mixed with crop oil concentrate at 2 pints/ Acre.

Okra (14 day PHI). Caparol 4L (EPA Reg’n No. 100-620). For control of broadleaf weeds apply Caparol 4L preemergence after seeding and before crop emergence at the rate of 3 pints/Acre. Alternatively, apply 1.5 pints/ Acre preemergence and a second directed-postemergence application of Caparol when the okra plants have 7-9 leaves and weeds are 2 inches tall or smaller.

Lettuce. Dual Magnum. (EPA Reg’n No. 100-816 EPA SLN No. OH-190001; for use in Ohio only). For control and suppression of annual grasses, yellow nutsedge and small-seeded broadleaf weeds.

• Leaf lettuce, seeded or transplant (25 day PHI). Apply Dual Magnum at 0.67-1.0 pints/ Acre preemergence to weeds either before crop emergence or transplanting. Alternatively, an over-the-top- or directed- postemergence application of Dual Magnum at 0.67 pints/ Acre can be made before weed emergence. If pre and post applications are used the total amount of Dual Magnum should not exceed 1.33 pints/ Acre per crop.

• Head Lettuce, seeded or transplant (20 day PHI). Apply Dual Magnum at 0.67-1.0 pints/ Acre preemergence to weeds either before crop emergence or transplanting. Alternatively, an over-the-top- or directed- postemergence application of Dual Magnum at 0.67-1.0 pints/ Acre can be made before weed emergence. If pre and post applications are used the total amount of Dual Magnum should not exceed 2.0 pints/ Acre per crop.

The research behind these new uses was paid for in part by the IR-4 Program, the Ohio Vegetable and Small Fruit Research and Development Program (OVSFRDP), and was only possible because we have a great network of OARDC research stations and personnel in key vegetable producing areas of the state. Thanks also to the various pest management supply companies that supported development of their products for use on specialty crops.