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.

Managing Phytophthora Blight and Pythium Root Rot in Peppers – Fungicide Update

Heavy rains early in the planting season favor both Pythium root rot and Phytophthora blight. While Pythium root rot is caused by several different species of Pythium with different temperature optima – cool to hot, Phytophthora blight is only favored by hot weather. Periods of hot, rainy weather following a cool wet spring can be a predictor of future problems with these diseases.

Young pepper plants killed by Phytophthora blight

Pepper plants (background) stunted by Pythium root rot

Phytophthora and Pythium are soilborne oomycete pathogens, also called water molds, that thrive in rainy weather. They produce motile spores (zoospores) that are attracted to plants, then form a structure that allows them to infect, and aggressively attack any type of plant tissue. Zoospores can be splashed onto leaves, stems and fruits during rain events and overhead irrigation. Phytophthora blight and Pythium root rot are often seen first in low spots or other poorly drained areas of production fields, but also occur on well-drained, even sandy soils if the environmental conditions are right. While Pythium root rot is not as explosive as Phytophthora blight, both must be managed preventatively.  Pepper varieties partially resistant to Phytophthora blight are available and should be used in fields with a history of this disease. There are no varieties with identified resistance to Pythium root rot. Cultural practices including crop rotation, good drainage, raised beds, avoiding surface water for irrigation, and sanitation should be used – see details here.

During the growing season, fungicide application is the main option for management of Phytophthora blight. Andy Wyenandt (Rutgers University) published a really nice piece on Phytophthora and Pythium control in peppers in April (https://plant-pest-advisory.rutgers.edu/phytophthora-control-during-wet-weather-3/). Fungicides must be applied preventatively for maximum benefit. Keep in mind that:

  1. Orondis Gold premix contains oxathiapirolin, which is very effective against Phytophthora blight (but not Pythium) and mefenoxam, which is effective against both Phytophthora and Pythium.  However, if mefenoxam (Ridomil Gold) or metalaxyl products have been used for a number of years in the same field, the Phytophthora population may be resistant.  We have found mefenoxam/metalaxyl-resistant Phytophthora capsici in Ohio in recent years. Orondis Gold can be applied through drip and in transplant water.
  2. Ridomil Gold can be applied to peppers as a soil spray or via drip, but not in transplant water. Under some conditions peppers can be severely damaged and unlikely to recover.
  3. The active ingredient in Orondis, oxathiapiprolin, does not move well through the soil profile. Our research has not shown a benefit of using Orondis as a soil application vs. foliar sprays. I recommend “saving” Orondis Ultra for foliar application when the weather is continuously conducive for Phytophthora blight.
  4. Elumin is a newer product for Phytophthora blight and application through drip or soil spray at transplanting is labeled, as well as foliar sprays during the season. Pythium root rot is not on the label for peppers but is labeled for Pythium in potatoes and related crops.
  5. Like Elumin, Ranman and Presidio are labeled for Phytophthora blight management in pepper, and not Pythium root rot; however, they are labeled for Pythium management in other crops.
  6. For Previcur Flex, Pythium root rot is on the label for peppers, but Phytophthora blight is not.
  7. The phosphites like ProPhyt and others are labeled for both Phytophthora and Pythium and are systemic.  The ProPhyt label allows drench application at transplanting although not in the transplant water per se.  However, it can be drenched onto seedlings prior to transplanting. The phosphites are good supplemental products but will not control Phytophthora blight alone. They should be used in tank mixes or rotated with products listed below.

Growers have a lot of choices, but if wet conditions continue and both Pythium root rot and Phytophthora blight are a concern:

  1. If Ridomil or related products have been used routinely on the farm or Phytophthora is known to be resistant to mefanoxam/metalaxyl, peppers should be treated with a soil application at or near transplanting with Ranman, Elumin or Presidio, followed by foliar applications in a rotation that includes Orondis Ultra, Presidio, Elumin or Ranman. These may be tank-mixed with a phosphite product.
  2. Keep in mind that a number of products such as Orondis Gold, Orondis Ultra and Elumin have strict use limitations – e.g. two applications per season. Check the label.
  3. Always rotate fungicides with different modes of action (FRAC codes):

Ridomil Gold: 4

Orondis Gold: U15+4

Orondis Ultra: U15+40

Elumin: 22

Presidio: 43

Ranman: 21

Previcur Flex: 28

Phosphite products: 33

 

 

Wayne County IPM Notes (Week of June 1- June 5)

These observations are from Frank Becker, Dept. of Extension Wayne County.

Vegetable Pests

The Colorado Potato Beetle is being seen feeding in both potato and eggplant. When approaching plants to look for them, be cautious. When the beetle is startled, they drop to the ground and may be difficult to see. They do significant damage to the foliage and can cause significant reduction in yield. The Colorado Potato Beetle also has a history of developing resistance to insecticides being used as control measures. This has limited our choices for treatment options. The best way to prevent further resistance is to avoid using the same insecticide repeatedly. At the current plant stage for potato, the threshold is approximately 1 beetle per plant. For eggplant, it is 25 beetles per 50 plants.

Another pesky insect this time of year is the flea beetle. Their damage may seem insignificant at first, however, their populations can rapidly increase and can quickly overwhelm young plants. Flea beetle damage is occurring primarily on potato, eggplant, cole crops and sweet corn. Sweet corn is of particular concern due to Stewart’s Wilt disease which is vectored by the flea beetle. Susceptible sweet corn varieties have a threshold of 6 beetles per 100 plants, while tolerant varieties have a threshold of 2 beetles per plant. On cole crops, the threshold is 5 or more beetles per plant. For potato, you will need to count the “shot holes” in the leaves caused by the beetle. The threshold is 15 shot holes per leaflet. Eggplants have a threshold of 8 beetles per plant.

In sweet corn, there is light slug damage occurring as well as some light damage being done by the European corn borer larva. Young sweet corn is also a target of black cutworm. The cutworm will cut plants at the soil line. If you find a cut plant, dig up some soil around the plant to see if you can find the cutworm.

Vegetable Diseases

In high humidity this time of year, greenhouse tomato crops become especially susceptible to infection from Botrytis. This can initially present itself on the fruit as “ghost spot” which appear as pale or white rings on the fruit. It can then progress into Botrytis gray mold and the fruit will begin to rot. It is important to increase airflow in the tunnel as well as between plants. It would also be beneficial to reduce the humidity within the tunnel.

Blossom end rot is also prevalent this time of year in crops such squash and tomatoes. Although this is not necessarily a pathogen, secondary infections commonly compound the issue. 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.

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 https://u.osu.edu/pestmanagement/ page.

Orchard traps are now out in Wayne County and we will be monitoring Codling Moth and Oriental Fruit Moth numbers closely.

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.

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 around the pre-bloom stage. 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.

Grafted Plants, Suppliers, and Experiments


Growers typically convert to using grafted plants (e.g., tomato, watermelon) primarily because they can be much more productive when specific soilborne diseases are present (and the correct rootstock is used). In addition, however, grafted plants are often more vigorous than ungrafted ones of the same scion (fruiting variety). Grafted plants may also use water, fertilizer, and other inputs more efficiently. Therefore, it is necessary to optimize cultural and fertility practices for grafted plant-based production. Two experiments will be completed in this 1+ acre parcel in 2020. One experiment tests alternative fertilizer rates and the second experiment tests in-row spacings (plant populations/acre). All grafted plants are supplied by Tri-Hishtil in Mills River, NC.

Tri-Hishtil (http://www.trihishtil.com/) is one among a constantly-lengthening list of commercial grafted plant suppliers. Others include Banner Greenhouses (https://www.bannergreenhouses.com/), Grafted Growers (https://graftedgrowers.com/), and Re-Divined (https://redivined.weebly.com/) in the eastern U.S. and others based in the west. Local suppliers are also operating in Ohio and some farmers are preparing their own grafted plants. Commercial suppliers continue to ramp-up their capacity to meet the needs of vegetable growers, regardless of the size, location, or type of their operation (field and/or high tunnel; conventional and/or organic). Also, grafted plant costs are increasingly competitive. Overall, access to grafted plants is strong and increasing and no longer a reason for being unable to test the performance of grafted plants on your farm. The Vegetable Production Systems Lab at OARDC can also assist, if needed; we teach people how to graft and, in 2021, we hope to resume preparing small numbers of plants by request.

One empty and three filled cells of a 128-cell tray holding grafted watermelon plants prepared by Tri-Hishtil. Note roots are visible on the surface as healthy white ‘threads’ with smaller root hairs near the tip, creating a bottle-brush appearance. Slotted cells (as shown at the bottom-left) contribute to this root condition and morphology.

Hand-grafted watermelon plants from Tri-Hishtil in Mills River, NC.
Plant at left is Jade Star and plant at right is Fascination, both grafted to Carnivor rootstock.
Clear and green clips show the location of the graft union and supports (white sticks) will be removed at planting (scheduled for 6/8/20).
Root systems are well-developed, stems are sturdy, and the plants pull easily. Roots are not spiraling, partly due to the larger size and special shape of the cells.
Clips can be removed at planting or allowed to be forced off naturally by stem growth.

Contact Matt Kleinhenz (330.263.3810; kleinhenz.1@osu.edu) and see updates at this blog for more information.

Transplants: Roots, Shoots, and Water

Transplant production continues for late-planted crops. The three panels below include observations on seedling root and shoot growth and a bottom-watering irrigation system.