The Annual Pumpkin Field Day Goes Virtual!

For over 20 years the pumpkin field day held at the Western Ag Research Station in South Charleston has hosted growers from around the state giving them a wide array of production and pest management research, demonstration, tips and tricks. Instead of driving over to the research station, participate virtually from your home, business or favorite coffee house / brewery!

Because of the Covid-19 pandemic, we won’t be able to hold a field day in person this year, but we are working hard to bring you the results of several demonstration and research projects via a pre-recorded video stream that will air on the OSU IPM YouTube channel on August 27 at 6 PM.

Registration for the virtual event will be necessary so we can send out the viewing links between August 26-27 for the roughly hour long field day. Please register at the link below by the deadline of August 25 at 8PM.

https://www.surveymonkey.com/r/vpumpkin2020

Presentations will include a late season weed screen including an update on the new Reflex herbicide label from Tony Dobbels; Celeste Welty will talk about managing key pumpkin pests; and Jim Jasinski will give updates on powdery mildew fungicides and on the mustard cover crop biofumigation project.

We are also preparing a video to highlight all of the pumpkin and squash hybrids in the variety trial. As a special encore, will be releasing a 3D field scale model of the pumpkin hybrid trial to allow participants to “walk” around in the field virtually, looking at the foliage and fruit of each hybrid in the trial. Here is a small sample of the 3D environment:

https://mpembed.com/show/?m=h5pvoP8inMs&mpu=454

3D field scale model of pumpkin hybrid trial – doll house view.

Brooke Beam will help manage the process by stitching together the short video presentations into one coherent movie which will be approximately 60 minutes long. Contact Jim Jasinski (jasinski.4@osu.edu) for more information or details. Hope to see you on August 27!

Bacterial Canker Showing Up in Tomatoes this Summer

Bacterial canker in fresh-market tomatoes.

Bacterial canker is a systemic disease of tomatoes caused by the bacterium Clavibacter michiganensis subsp. michiganensis. It can occur in fresh market and processing tomatoes, in open fields and in protected culture systems like greenhouses and high tunnels. Symptoms are stunting of whole plants, which never reach their full potential, plant death,

Bacterial canker on tomato leaves.

foliar lesions, “firing” on leaf margins and raised scabby lesions on fruit. Seeds are a major means of introducing the canker pathogen into a tomato crop, but the bacteria can survive in the field for several years, as well as on surfaces such as greenhouse walls or floors, tools, stakes, clips or ties, etc. Several cases of tomato canker have come into our diagnostic lab this summer; since the bacteria clog the plants’ water-conducting vessels, the stunting symptom may be more severe in the hot, dry weather we’ve experienced for much of this year’s growing season.

Bacterial canker symptoms inside a tomato stem.

Peppers are also susceptible to bacterial canker, but the disease is not systemic in peppers so the stunting symptom does not occur. However, firing of the leaf margins and leaf and fruit lesions do occur. Symptoms of bacterial canker on peppers are different than those on tomatoes (see figures). The bacteria that infect

Bacterial canker symptoms on pepper leaves.

tomatoes are the same as those infecting peppers, so infected peppers can be a source of bacterial inoculum for tomatoes and vice versa. Bacterial canker is relatively rare in peppers; if you suspect it please consider sending a sample to our diagnostic lab.  The service is free for Ohio vegetable growers.

Bacterial canker lesions on pepper fruit.

There are no bactericides or other products that control this disease once it is in the field or greenhouse. This disease is managed primarily through sanitation.

  • Start with clean seed – For purchased seeds, buy certified, disease-free seed or sanitize seed with hot water (recommended), dilute bleach or hydrochloric acid. It is especially important to sanitize saved seeds, such as for heirloom varieties. Here is a link to the OSU fact sheet for Hot Water and Chlorine Treatment of Vegetable Seeds to Eradicate Bacterial Plant Pathogens. In place of water baths for the hot water treatment, relatively inexpensive Sous Vide – type digital water heaters can be used too heat and maintain the water at the prescribed temperature.
  • Keep transplants clean and healthy – Scout tomato and pepper plants daily and destroy plants with canker symptoms once a plant disease diagnostic laboratory has confirmed the disease. Apply one or two preventative copper fungicide applications and one application of streptomycin (conventional systems) to the plants before transplanting them into the field.
  • Use clean equipment and tools – Clean and disinfect all tools and farm equipment prior to working with the transplants or plants. Good sanitation practices are critical to prevent contamination and cross contamination of plants by the bacterial canker pathogen. Quaternary ammonium products and 10% chlorine bleach are suitable disinfectants.
  • Start with a clean field – The bacterial canker pathogen can survive in the field as long as there is infected crop debris present. Rotate with a non-host before re-planting the field with tomato. Ideally a 3-4 year out of crops in the same family as tomato (pepper, eggplant) should be implemented. Plant into a field free of weeds or volunteer tomato plants.
  • Use best cultural practices – Use management strategies that maintain reduced-stress growing conditions. Provide plants with adequate but not excessive nitrogen, improve the organic matter content of the soil through the use of composted green or animal waste or cover crops, use well-drained soil and avoid overhead irrigation if possible.

 

 

 

 

 

 

 

Wayne County IPM Notes for July 19-July 25

Wayne County IPM Notes

Vegetable Pests

            Hot and dry conditions are often ideal for spider mites to thrive, and this year is no different. Spider mites proliferate during these conditions and are currently doing so in melon plantings. They feed on the undersides of the leaves and their feeding damage over time can cause chlorosis and stippling, and eventually the leaf will shrivel and die. More on spider mite management

Cucumber Beetles are feeding again, primarily on young, recently transplanted squash. However, the adults are not the only ones causing damage. The larvae of the cucumber beetles have also been doing damage. I have seen damage to the skin of melons where the melon is sitting on the soil. This contact area between the ground and the melon provides the perfect place for cucumber beetle larva to feed.

 

Tomato hornworm that was feeding on tomato plants. F. Becker photo.

I have started to see a decent amount of damage from tomato hornworms. Be sure to keep an eye on your tomato plants for large areas of defoliation near the top of the plant, as well as damage to the fruit. Tomato hornworms may also feed on Solanaceous plants such as peppers, eggplant and potato, although not to the extent of which they feed on tomato plants.

Japanese beetles are out in large numbers on a wide range of crops. Sweet corn growers should be especially wary of Japanese Beetles feeding since one of their target areas on sweet corn is the silk. The beetles can clip the silk which limits the silk’s receptivity to pollen.

Vegetable Diseases

            Downy Mildew has now been detected and confirmed in Wayne County. Cucumber growers should have started a spray program for cucurbit downy mildew.

Powdery mildew is starting to show up on cucurbit crops around the area. If older plantings of summer squash are heavily infested and you are no longer harvesting from those areas, it would be of your best interest to terminate that crop so that you are not allowing the powdery mildew to have a place to thrive. This is especially important if you have younger, successive plantings of summer squash nearby.

This week, the lab at OARDC confirmed bacterial leaf spot on pepper. Bacterial infections have been limited this year due to the heat and dry weather, however, they should still be managed appropriately. This is one of the most destructive diseases for peppers and will result in a yield reduction due to loss of foliage and infection on the fruit.

Bacterial wilt is starting to show up in older squash plants, unfortunately at this point there is nothing that can be done. The cucumber beetles feeding on the plant while it was young vectored the bacteria responsible for bacterial wilt and the plant is finally being impacted by the infection.

Fruit Pests

Grape berry moth larvae are starting to feed and cause damage in grape clusters. Scouting grapes and carefully assessing the grape clusters can help you determine management needs. Infestations of grape berry moths are typically higher along the borders, and near woods or hedge lines as compared to the interior of the vineyard.

Spotted Wing Drosophila numbers are remaining high. Other than spraying insecticides such as malathion, it is beneficial to limit the

Grapes damaged by grape berry moth. F. Becker photo.

amount of overripe/cull fruit that is on the ground around the plants. The fruit on the ground only attracts more flies and in encouraging good sanitation in the patch it can help reduce the number of flies being drawn in.

Codling Moth traps have started to show increasing numbers, with some inconsistency, but nonetheless, the counts have trended up. Oriental fruit moth traps spiked this week, going from essentially 0 per trap to averaging between 7 and 8 per trap.

Japanese beetles are feeding across the spectrum of fruit crops that I am scouting. I have noticed heavy damage primarily occurring on ripe blueberries and on grape leaves. Left uncontrolled, the Japanese beetles can cause significant damage to blueberries and severe defoliation in grapes.

Fruit Diseases

            Apple and peach growers should continue their spray programs to manage fruit rots and diseases such as flyspeck and sooty blotch in apples and brown rot in peaches. Alternaria leaf blotch can be found on some apple trees right now. This can be made worse by red mite infestations. With high populations of mites and the leaf blotch, severe defoliation can occur.

Grapes should be starting to get some color to them as the clusters are starting to increase in size. At this point, most varieties of grapes should be resistant to black rot. Although symptoms of black rot may be showing up on untreated grapes, it is too late to do anything.  Growers with varieties of grapes that are not resistant to downy mildew should consider a spray program. Grape growers should also keep an eye out for powdery mildew, as this is the time of year when powdery mildew is typically found on grapes.

Cucumber Downy Mildew Confirmed in Sandusky County in Ohio

Downy mildew was confirmed today on cucumbers in our sentinel plot on the OSU North Central Agricultural Research Station in Fremont and a home garden in Clyde, both in Sandusky County.  This follows reports for cucumbers in Medina and Wayne Counties earlier this month. As I’ve indicated in previous posts, we believe that cucumber downy mildew has been present in northern Ohio counties for several weeks; growers should be protecting cucumbers with recommended fungicides.  We haven’t had reports of downy mildew on melons (cantaloupe) but melons are susceptible to the strain of the downy mildew pathogen circulating in northern Ohio, as are giant pumpkins. So these crops should also be protected now with fungicides.

Garden cucumbers with downy mildew

While downy mildew does not cause lesions on fruit, it does reduce yield significantly by damaging and eventually killing the foliage.  Growers who stop harvesting fields with severe downy mildew should destroy the plants as soon as possible to eliminate this source of inoculum. The pathogen does not survive in the soil.

Home gardeners who choose to treat cucumbers or melons with a fungicide should purchase a product containing chlorothalanil and start applications before the disease appears.  If the disease becomes severe gardeners should destroy the plants to reduce local inoculum.

Cucurbit Downy Mildew is Spreading in Ohio Despite Hot Weather

Micrograph of a tape mount of spores and sporangiophores of the cucurbit downy mildew pathogen from cucumber leaves. Photo by Francesca Rotondo.

Downy mildew continues to spread in Ohio cucumbers despite the hot and mostly dry weather.  Frank Becker, OSU Extension Wayne County IPM Program Coordinator, brought cucumber leaves with downy mildew symptoms to to our Vegetable Pathology Lab on July 23 for confirmation. We do this by placing a piece of scotch tape on the underside of a leaf lesion then transferring to tape to a glass slide and looking for characteristic spores and sporangiophores (branched, threadlike structures that produce the spores) under a microscope. The samples came from commercial cucumber fields in Wooster and Apple Creek in Wayne County, and both were positive for downy mildew.

Cucurbit downy mildew as of July 24, 2020. cdm.ipmpipe.org.

Although we have confirmed reports in only Medina and Wayne counties, cucurbit downy mildew is likely present in most northern Ohio counties.  The map of downy mildew reports shows confirmed cases in Ontario, Michigan and western New York as well. All of these reports are from cucumbers; this clade, or strain of the pathogen affects cucumbers and cantaloupe, but not squash or pumpkins. We don’t expect downy mildew on squash and pumpkins until the other known clade, which has a broader host range, migrates to the Midwest from the Southeast.

Downy mildew in cucumber.

Fungicide recommendations are posted here.  If you suspect downy mildew in any cucurbit, please send us a sample.  This will help us track the disease and provide early warnings to growers to enable timely protection of cucurbit crops. Our diagnostic service is free to commercial growers in Ohio; gardeners may also send cucurbit downy mildew samples to us free of charge.  Instructions for sample submission are posted here.

 

Wayne County IPM Notes from July 12-July 18

Wayne County IPM Notes

Vegetable Pests

            Squash Bugs are starting to lay large numbers of egg masses on summer squash, gourds, and pumpkins. Large numbers of squash bugs feeding can cause leaves to yellow and eventually die which can significantly reduce yield.

Japanese beetles on summer squash. F. Becker photo.

Cucumber Beetles are feeding again, primarily on young, recently transplanted squash. This is a important time to work on control of cucumber beetle as with young plants, the cucumber beetles can cause severe damage, stunt the growth of the plant and may lead to plants going down later with bacterial wilt.

Potato Leaf Hoppers (PLH) still have very high populations in several crops this year. PLH cause “hopper burn” on the leaves on which they are feeding. I have seen this damage to potatoes and green beans.

Japanese beetles are feeding in basically every crop that I scout. Sweet corn growers should be especially wary of the Japanese Beetles feeding since one of their target areas on sweet corn is the silk. The beetles can clip the silks and affect the success of the pollination. More on Japanese beetles and other sweet corn pests.

Vegetable Diseases

            Downy Mildew has been confirmed, again, in Medina County. Cucumber growers should have started a spray program for the cucurbit downy mildew.

Powdery mildew is starting to show up on cucurbit crops around the area. If older plantings of summer squash are heavily infested and you are no longer harvesting from those areas, it would be of your best interest to terminate that crop so that you are not allowing the powdery mildew to have a place to thrive. This is especially important if you have younger, successive plantings of summer squash nearby.

Powdery mildew starting to show on summer squash. F. Becker photo.

Some field tomatoes are showing symptoms of early blight. Early blight is a common tomato disease and happens when soil is splashed up onto the older, lower leaves. If not treated, early blight can cause significant defoliation of a plant.

In melon patches, specifically in cantaloupe, there is some Alternaria leaf blight showing up. This disease primarily affects the foliage but if the infection is severe enough, it may also infect the fruit.

Although not technically a disease, blossom end rot is still affecting a lot of crops. This is technically a deficiency of calcium in the plant but not necessarily in the soil. The best way to attempt to prevent further issues is to have consistent moisture to the plant and provide an environment conducive to adequate nutrient uptake.

Fruit Pests

Grape berry moth larva feeding inside a grape. F. Becker photo.

I have started to see grape berry moth larvae feeding in grape clusters. Scouting grapes and carefully assessing the grape clusters can help you determine management needs. Infestations of grape berry moths are typically higher along the borders, and near woods or hedge lines as compared to the interior of the vineyard.

Spotted Wing Drosophila numbers are still increasing. The trap counts were up again this week, with all the traps being in blueberry patches.

Codling Moth and Oriental Fruit Moth trap counts were low again this week and showed very little activity.

I am still seeing red mites in apple orchards throughout the county. Feeding by large populations of red mites can cause leaves to “bronze” and when left uncontrolled, this heavy feeding could result in leaf drop and a reduced size and quality of the crop. This hot and dry weather has been ideal for the red mite populations to get established in orchards.

Japanese beetles are feeding across the spectrum of fruit crops that I am scouting. I have noticed heavy damage primarily occurring on ripe blueberries and on grape leaves. Left uncontrolled, the Japanese beetles can cause severe defoliation in grapes.

Fruit Diseases

            Alternaria leaf blotch can be found on some apple trees right now. This can be made worse by red mite infestations. With high populations of mites and the leaf blotch, severe defoliation can occur.

Apple and peach growers should continue their spray programs to manage fruit rots and diseases such as flyspeck and sooty blotch.

Grapes should be starting to get some color to them as the clusters are starting to increase in size. At this point, most varieties of grapes should be resistant to black rot. Growers with varieties of grapes that are not resistant to downy mildew should consider a spray program. Find more here on grape diseases.

Blossom End Rot of Peppers

 

Blossom end rot of bell pepper

The hot, dry weather of the last few weeks has been stressful for peppers, resulting in the appearance of blossom end rot, especially in early fruit sets. Blossom end rot is the result of plant stress brought on by periods of dry vs moist soil.  Calcium deficiency in the plant is the cause but applying calcium to the foliage won’t help.  Calcium is relatively insoluble and plants under stress can’t move it to flowers and developing fruit.  It is a vital component of plant cell walls and the matrix that holds the cells together. When fruits start to form without sufficient calcium the tissues soften and die.  Secondary molds often colonize the dead tissue.

Blossom end rot of bell pepper

Blossom end rot becomes less problematic with more consistent soil moisture and as the plants grow and develop their root systems.

Blossom end rot of bell pepper

Another fruit problem reported recently and related to hot, sunny weather is sunscald. Sunscald can appear similar to blossom end rot – it appears on the part of the fruit exposed to the sun.  Sunscald spots are tan in color, and eventually become dry and papery. There isn’t much that can be done about sunscald except to encourage good foliage coverage by appropriate fertilization.

Sunscald of bell pepper

Anthracnose also causes lesions on pepper fruit, but the disease is caused by a fungus dispersed by rainsplash (or overhead irrigation); it is less severe in dry than rainy weather.  This disease is managed by application of fungicides.

Thanks to Carri Jagger for the blossom end rot and sunscald photos.

Bacterial Disease Management in Vegetable Crops without Copper?

The 2020 vegetable growing season has been relatively hot and dry in most of Ohio, resulting in fewer reported serious outbreaks of bacterial diseases. However, circumstances can change and bacterial diseases may need to be managed. Unfortunately, options for bacterial disease management at the field stage are limited.

Bacterial spot on tomato fruit

Copper-based products, often paired with mancozeb or related products, have been the mainstay for bacterial disease management in vegetables for decades. Copper treatment is only partially effective under rainy conditions that favor bacterial diseases, when disease pressure is moderate to high. Further, research conducted in Ohio and other states has shown that copper resistance is widespread in the Xanthomonas bacteria that cause bacterial spot in tomatoes and peppers, rendering these products mostly ineffective. We are no longer recommending copper treatments for bacterial spot management in tomatoes or peppers.  We have less information about other bacterial pathogens but copper resistance is possible in other Xanthomonas species as well as other pathogens such as Pseudomonas and Clavibacter.

There are a few other options for bacterial disease management (see table below) that are grouped into roughly three categories: 1) plant resistance activators/inducers, 2) antimicrobials, and 3) bacteriophage. Keep in mind that none of these products fully control bacterial diseases under moderately to highly conducive conditions. In our research with bacterial spot of tomatoes, Actigard applications consistently reduced bacterial spot damage to foliage, although the incidence of fruit lesions was less consistently reduced and yield not improved compared to the non-treated control in small plot trials.  Actigard is labeled for bacterial disease management in brassicas, cucurbits, tomatoes and non-bell peppers. The other resistance inducers in this group have been shown to suppress bacterial diseases but there is inconsistency and lack of control under highly conducive conditions.

Products in the antimicrobials group also have been shown to suppress bacterial diseases, but again, results vary among trials and these products are not effective under highly conducive conditions. In our experience, under low to moderate disease pressure, disease severity is often significantly reduced compared to non-treated plants.  As a rule of thumb, the reduction in symptom severity ranges from about 25-40%. If these products are going to be used, they should definitely be applied preventatively to keep bacterial pathogen populations low.

Finally, AgriPhage is a product that contains antibacterial viruses (phage) that infect and kill specific bacterial pathogens. There are different mixtures of phage for different pathogens.  This product also must be applied early in an epidemic.

Product

Type Manufacturer Crops labeled

Plant Resistance Inducers

Actigard Plant activator Syngenta Bacterial diseases of brassicas, cucurbits, tomato, non-bell pepper
Regalia Plant (Reynoutria) extract, plant resistance inducer Marrone Bio Innovations Most vegetables
Taegro 2 Bacillus subtilis var. amyloliquefaciens FZB24 Novozymes BioAg Inc. Bacterial diseases of fruiting vegetables
Vacciplant Laminarin, plant defense stimulant UPL Fruiting vegetables, brassicas, leafy vegetables
Antimicrobials
Double Nickel Bacillus amyloliquefaciens D747 Certis USA Most vegetables
LifeGard WG Bacillus mycoides J Certis USA Most vegetables
Serifel

Serifel NG

Bacillus amyloliquefaciens MBI600 BASF Most vegetables
Serenade ASO

Serenade Opti

Bacillus subtilis QST-713 Bayer CropScience Most vegetables
Stargus Bacillus amyloliquefaciens F727 Marrone Bio Innovations Most vegetables
Antibacterial Viruses
AgriPhage Antibacterial phage (type of virus) Certis USA Most vegetables

Given the inadequacies of these “rescue” treatments for bacterial disease management, proactive approaches should be undertaken:

  • Start with seeds tested for bacterial diseases; if not possible, treat seeds with hot water or dilute Clorox.
  • Create conditions during transplant production that discourage bacterial pathogen multiplication on plants – dry growing, good air circulation, low relative humidity.
  • Apply labeled antimicrobials (see Table) to seedlings in the greenhouse.
  • Sanitize transplant houses after seedlings are moved to the field.
  • Sanitize vehicles and equipment prior to transporting and transplanting seedlings.
  • Use new or sanitized stakes each season.
  • Sanitize pruning tools after each plant (tomatoes).
  • If possible remove and destroy diseased plants.
  • Practice regular crop rotation.

 

 

Wayne County IPM Notes from July 5 – July 11

Vegetable Pests

            In sweet corn, the European corn borer (ECB) larvae are still doing damage. This week I started seeing some corn earworm (CEW) damage as well. The ECB trap counts dropped and showed little activity but the CEW traps started to increase in numbers. Even if the ECB activity seems to be slowing down, you need to be scouting your sweet corn for the CEW as well.

Squash bug egg mass on a zucchini leaf. F. Becker photo.

Squash Bugs have started to make their presence known. I have started seeing squash bug adults, primarily in summer squash plantings. I have also started to find squash bug egg masses. Large numbers of squash bugs feeding can cause leaves to yellow and eventually die which can significantly reduce yield.

Flea beetles are still very active and on a wide range of plants. Damage can be seen primarily on cole crops and potatoes.

Potato Leaf Hoppers (PLH) have high populations in several crops this year. PLH cause “hopper burn” on the leaves on which they are feeding. I have seen this damage to potatoes and green beans. Some of the PLH populations within green bean plantings have been incredibly high, in some cases, over 40 PLH per single leaf.

Potato leaf hoppers feeding on a green bean leaf. F. Becker photo.

Hopper burn from potato leaf hopper feeding on green beans. F. Becker photo

Vegetable Diseases

            Downy Mildew has been confirmed in Medina County. Cucumber growers should have started a spray program for the cucurbit downy mildew.

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.

Cucurbit downy mildew on cucumber leaves. F. Becker photo.

Some field tomatoes are showing symptoms of early blight. Early blight is a common tomato disease which gets its start typically on the older, lower leaves. If not treated, early blight can cause significant defoliation of a plant.

In some melon patches, specifically in cantaloupe, there is some Alternaria leaf blight showing up. This disease primarily affects the foliage but if the infection is severe enough, it may also infect the fruit.

Fruit Pests

Spotted Wing Drosophila numbers are still increasing. The trap counts were up again this week, with all the traps being in blueberry patches.

Codling Moth and Oriental Fruit Moth trap counts were low again this week and showed very little activity.

I started to find red mites in apple orchards throughout the county. Feeding by large populations of red mites can cause leaves to “bronze” and when left uncontrolled, this heavy feeding could result in leaf drop and a reduced size and quality of the crop. This hot and dry weather has been ideal for the red mite populations to get established in orchards. Read more on Red Mite Management.

Mites feeding on an apple leaf. F. Becker photo.

Fruit Diseases

            Alternaria leaf blotch can be found on some apple trees right now. This can be made worse by red mite infestations. With high populations of mites and the leaf blotch, severe defoliation can occur.

Apple and peach growers should continue their spray programs to manage fruit rots and diseases such as flyspeck and sooty blotch. Managing Apple and Peach Summer Diseases

Grapes should be starting to get some color to them. At this point, most varieties of grapes should be resistant to black rot. Growers with varieties of grapes that are not resistant to downy mildew should consider a spray program.

Wayne County IPM Notes from 6-28 to 7-4

 

ECB damage to sweet corn tassel. F. Becker photo.

European Corn Borer has been doing damage in tasseling corn. The small ECB larva feed in the tassels as well as the developing 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. The ECB moth traps were high again this week, which is consistent with the amount of damage being done in early planted sweet corn.

Japanese Beetles are also starting to increase in number. They are a pest on most any crop. They can be especially damaging to sweet corn. The beetles can defoliate the leaves, but they can also clip the silks which can prevent proper pollination from occurring.

Worm feeding on cole crops has really started to pick up. I am finding a lot of imported cabbageworms doing damage on all ages of cole crops such as cabbage and kale. The adult butterflies can be seen in large numbers in cole crop plantings laying eggs on the plants. Read more here on pests of crucifers. I saw an uptick in the population of the flea beetle as well. Keep in mind that especially on younger plants, the flea beetles can cause a lot of damage and may stunt the plant.

Imported Cabbageworm larva on cabbage. F. Becker photo.

This hot and dry weather has been perfect weather for onion thrips. The thrips population has been high already in some areas, so this weather is favorable for large populations of thrips to develop. The thrips feeding can open the plant up to diseases such as purple blotch, so early detection and management are crucial to maintaining the health of the plant.

Vegetable Diseases

            Downy Mildew has been confirmed, again, in southern Michigan. Considering the proximity to Ohio, it has been recommended that cucumber growers begin a downy mildew fungicide program immediately. “Managing Downy Mildew in Cucurbits”

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.

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.

Angular leaf spot has started to show up on some cucurbit crops, however, the hot and dry weather has helped slow it down or stop its progression altogether. Angular leaf spot is a bacterial disease, meaning that fungicides are not effective for management of this disease.

Fruit Pests

SWD female with a serrated ovipositor. F. Becker photo.

Spotted Wing Drosophila are here. All the traps out in Wayne County were positive for SWD. These traps are out in blueberry and strawberry patches. Strawberries are winding down, but blueberries and raspberries getting ripe should be managed accordingly.

Codling Moth and Oriental Fruit Moth trap counts were down this week. Another week with our traps not over threshold.

Keep an eye out for aphids and mites in orchard crops. We are getting into the time of year where aphid and mite populations begin to increase and can do so rapidly. Leafhoppers are also a pest to be on the look out for, especially in grapes. More on Spider Mites

Fruit Diseases

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

Peach “mummy” still present in a tree this spring. F Becker photo.

Necrotic leaf blotch and Alternaria leaf blotch can be found on some apple trees right now. Alternaria leaf blotch can be made worse by red mite infestations. With high populations of mites and the leaf blotch, severe defoliation can occur. More on foliar apple diseases: Leaf Spots

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.

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.