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.

Beware of thrips!

The current hot, dry weather can be conducive to outbreaks of thrips. Thrips are very small, slender, elongate, cigar-shaped insects, about 1 mm (1/25 inch) long. They differ from other insects by having thin strap-like wings that are fringed with hairs. The wings are usually folded lengthwise over the back when they are resting or feeding, as shown in the image below. They have asymmetrical mouthparts that have a well-developed left mandible and an underdeveloped right mandible. They feed by piercing plant cells by the mandible then sucking sap that oozes out of the punctured cells.

Smaller, tan thrips on left is the onion thrips (Thrips tabaci). Larger yellowish thrips on the right is the western flower thrips (Frankliniella occidentalis).
Photo by Alton N. Sparks, Jr., University of Georgia, Bugwood.org

Thrips generally have flowers as their preferred plant part but they also feed on leaves and fruits. They are found in flowers of many ornamental plants but also on various vegetables and fruit crops, including tomatoes, peppers, and cucumbers. Thrips are often overlooked due to their small size and their tendency to hide in protected places. When present at low density, thrips are usually not harmful to crops, but when they reach higher density, they can feed on the surface of fruits and cause injury.

The thrips species that infests many outdoor crops is Frankliniella tritici, which has the official common name of ‘flower thrips’, but which is widely known as the eastern flower thrips. The thrips species that is most common in greenhouses is the western flower thrips, Frankliniella occidentalis, which is generally much more difficult to control than other thrips because it is not highly susceptible to most insecticides. A third common species is the onion thrips (Thrips tabaci), which is a serious pest of dry bulb onions and green onions as well as cabbage.

Natural enemies of thrips are Orius flower bugs, which are very small predatory true bugs that prey on thrips as adults and nymphs. Orius insidiosus is a common species in Ohio that is frequently found on the moist fresh silks of sweet corn and on flowers of Queen Anne’s lace. There are also several species of predatory mites that prey on thrips.

Insidious flower bug (Orius insidiosus) feeding on an insect egg.
Photo by John Ruberson, Kansas State University, Bugwood.org

 

Orius bug feeding on a thrips.
Photo by Robert Webster / xpda.com / CC-BY-SA-4.0 via Wikimedia Commons.

Thrips can be monitored by shaking flowers over a paper or into a cup or zip-top sandwich bag, which should then be examined for the dislodged thrips running around on the surface. Action thresholds have not been developed for most crops, but on strawberry we use a threshold of 2 thrips per flower.

In the past, pyrethroid insecticides provided control of thrips, but there are widespread observations that pyrethroids are no longer very effective for thrips control at most locations. Newer insecticides used to control thrips on conventional crops include Radiant, Assail, and several others, as shown in Table 1 below. Products for thrips control on organic crops include Entrust and various others as shown in Table 2 below.

If a biological control approach is preferred, natural enemies are available for purchase from commercial insectaries for thrips control: Orius (predatory flower bugs), and two species of predatory mites: Amblyseius cucumeris and Ambylseius swirskii. Beneficial nematodes such as Steinernema feltiae are another option. Microbial options include sprays of the beneficial fungus Beauveria bassiana, which is found in several commercial products. Biocontrol is not feasible to begin once the thrips population is large but can be planned in advance at locations that have a consistent problem with thrips.

-Celeste Welty, Extension Entomologist

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.

Worms in mid-summer sweet corn

Mid-July should be one of the easiest times to keep sweet corn ears free from caterpillar pests because none of the three key pest species are now abundant in Ohio, and many acres of grain corn are now silking and offering a good habitat to the few corn pests that are active. Once the large fields of grain corn are past the fresh-silk stage, then any plantings of late sweet corn will become very attractive to corn pests. We have had detection of some corn earworm moths but at low to moderate density. At present, we are between generations of European corn borer, but the moths of the new generation are likely to begin emerging in the next week or two.

However, the western bean cutworm is a 4th caterpillar species that is becoming a key pest of sweet corn, particularly in July and August, particularly in northwest Ohio. This is a key pest to look for over the next week. This pest is a caterpillar feeds on kernels of ears in both sweet corn and field corn. Feeding damage is usually at the tip end of the ear, but can be in the middle or butt end of the ear. There are often several western bean cutworm larvae in one ear, which makes it different than the corn earworm, that also feeds on kernels at the tip of the ear, but which typically is found as a single larva per ear. The newer BT sweet corn hybrids in the Attribute II series (from Syngenta) provide genetic control of the western bean cutworm, but BT sweet corn hybrids in the Performance series (from Seminis) and the older Attribute series (from Syngenta) do not control this pest. Pheromone traps detected the first activity of this moth this year during the week of 5 – 11 July in Sandusky, Champaign, and Clark Counties. Once the moths are detected, sweet corn fields should be scouted to monitor eggs and young larvae. Scouting should concentrate on plantings in the emerging-tassel stage. Look at 20 consecutive plants in each of 5 random locations per field. Examine the flag leaf (the leaf below the tassel), where eggs are usually laid. Eggs are laid in masses. Eggs are white when fresh, then they darken to purple when ready to hatch. Hatch will occur within 24-48 hours once eggs turn purple. Our tentative threshold for sweet corn is to consider treatment if eggs or larvae are found on more than 1% of plants for fresh-market or on more than 4% of plants for the processing market. Insecticide applications must occur after egg hatch, or after tassel emergence, but before larvae enter the ear. Pictures and additional details on western bean cutworm can be found in our OSU fact sheet: http://ohioline.osu.edu/factsheet/ENT-40 . Trap reports on western bean cutworm from several Ohio locations can be found using this link: https://docs.google.com/spreadsheets/d/10gh3rHahdxLKkXQapGyEPxWsjHYRmgsezOoFHnwtyEo/edit#gid=441280294

Corn earworm moths are present at low to moderate density as detected by pheromone traps at six Ohio locations; catch ranged from 0 to 11 moths per trap in the past week. This is slightly down from a few weeks ago when trap catch was 12-15 at some sites. The corn earworm moths will be laying their eggs on silks of sweet corn. Sweet corn can be protected from corn earworm infestation by insecticide sprays during silking. When the number of CEW moths caught in traps is moderate (1 to 13 moths per day, or 7 to 90 moths per week), then sprays should be applied every 4 days if the daily maximum temperatures is below 80 degrees F, or every 3 days if the daily maximum temperatures is above 80 degrees F. More information about trap-based spray schedules is available using this link: http://u.osu.edu/pestmanagement/crops/swcorn/ . Trap reports on corn earworm from several Ohio locations can be found using this link:  https://docs.google.com/spreadsheets/d/10gh3rHahdxLKkXQapGyEPxWsjHYRmgsezOoFHnwtyEo/edit#gid=0

True armyworm moths are still more abundant than usual this year and remain a threat to young late-planted sweet corn. Young plantings should be scouted. Our threshold rule is to treat by spraying insecticide if 35% of plants are infested during seedling or early whorl stages. Trap counts for armyworm moths in Columbus can be found for pheromone traps : https://docs.google.com/spreadsheets/d/10gh3rHahdxLKkXQapGyEPxWsjHYRmgsezOoFHnwtyEo/edit#gid=1122468773 , and daily counts for armyworm moths in a blacklight trap are shown here:

https://docs.google.com/spreadsheets/d/10gh3rHahdxLKkXQapGyEPxWsjHYRmgsezOoFHnwtyEo/edit#gid=1114468121

 

-by Celeste Welty, Extension Entomologist

Colorado potato beetle control on potato, eggplant, and tomato

There are reports from Ohio farms that pyrethroid insecticides are no longer providing adequate control of Colorado potato beetles (CPB). Pyrethroids include Warrior, Baythroid, Brigade, Mustang Maxx, Asana, Pounce, and Ambush.

There are several newer insecticides that are effective for control of CPB populations, but most of these are best at killing the larvae rather than the adults of CPB. Products that provide good control of larvae are Agri-Mek (abamectin), Radiant (spinetoram), Coragen (chlorantraniliprole), Harvanta (cyclaniliprole), Rimon (novaluron), and Torac (tolfenpyrad).

A good biopesticide option for control of young larvae of CPB is Trident, which has Bacillus thuringiensis tenebrionis as the active ingredient. This is the same a.i. that was found in several products that are no longer readily available: Novodor and M-Trak. Trident is on the OMRI list of products allowed on organic crops. Other good options for control of CPB on organic crops are Entrust (spinosad) and azadirachtin products such as Aza-Direct, AzaGuard, Azatrol, Molt-X, and Neemix.

Among somewhat older insecticides, the neonicotinoids are still effective at most locations; these are listed in the table below. The neonicotinoids are generally more effective by soil application, which provide true systemic control, whereas application by foliar sprays provides translaminar control but not true systemic control throughout the plant. Some of the neonicotinoids are allowed only for soil applications, some for only foliar sprays, and some for either method. If used for soil application, usually at planting time, then later foliar applications are not allowed.

Table 1. Insecticides in the neonicotinoid group used for control of Colorado potato beetle on potato, eggplant, tomato, and peppers by soil or foliar application; ‘yes’ means allowed, ‘no’ means not allowed.

by Celeste Welty, Extension Entomologist

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.

Ready to manage spider mites?

With the current hot and dry weather conditions in Ohio, we expect to hear reports of spider mite outbreaks on specialty crops. Because mites are tiny, they are often overlooked or misdiagnosed as a disease. Infested leaves have fine webbing on the leaf undersides. Tomato leaves damaged by spider mites usually have yellow blotches, while bean leaves show white stipples or pin-prick markings from mite feeding. Pumpkins can tolerate moderate levels of mites, but watermelons are more sensitive to injury from mite feeding. A simple method of diagnosing spider mites is to shake leaves over a piece of paper and look for moving specks that are visible to the naked eye. A closer look with a magnifier can show the tiny mites that are white, marked with two large dark spots on the middle of the body.

Mites have many natural enemies that kill them, such as specialized predatory mites or generalist lacewings, ladybugs, and pirate bugs, but these helpful predators are often killed by pesticides. Mites can be suppressed by periodic overhead irrigation.

Chemical intervention can be needed to keep the crop alive if spider mites are abundant. In some fields, the mite infestation is worst on a field edge by a dusty road. When a mite infestation is limited to field edges, infested fields should be scouted, and a miticide applied as a spot treatment to isolated infestations. Mite control is better when higher volumes of water are used; 30 to 50 gallons of water per acre is better than 10 gal/A.

Several pesticides are registered for spider mite control; some are restricted use, and most are for general use. Some of these products kill only the motile mites (immatures and adults), while some kill eggs. Most do not have systemic activity but some do. These details are summarized in three attached tables. One table shows details about target life stages and mite species affected, as well as any insect target pests. Another table shows details about which products are registered for use on key vegetable crops, and another table for show similar registrations for hops and fruit crops.

At some locations, the old organophosphate Dimethoate is still effective for mite control. Dimethoate is an option for melons but is not allowed on squash or cucumbers; it has been a preferred product for mite control on soybeans. Dimethoate is prohibited from use on ornamental crops in high tunnels and greenhouses but is not prohibited from vegetable crops in high tunnels and greenhouses. Where Dimethoate is not effective, Agri-Mek (abamectin) is generally the most effective product for mite control but it is a restricted-use product, while Acramite (bifenazate) and Oberon (spiromesifen) are nearly as good but are not restricted-use products. Other options for some crops are Portal, Envidor, Zeal, Nealta, Onager, Savey, Apollo, and Kanemite, as well as a new product called Magister. Although Brigade (bifenthrin) and Danitol (fenpropathrin) are labeled for spider mite control when used at the high end of the rate range, they are generally not as effective as the true miticides. Vydate (oxamyl) is a Restricted Use product that is registered for use on eggplant for mite control. Several broad-spectrum products are available for use on organic farms to control mites as well as various insect pests: Grandevo, PFR-97, Sil-Matrix, SucraShield, as well as sulfur, oils, and insecticidal soap (such as M-Pede or Des-X). Soaps and oils can be used for mite control, but thorough coverage of the undersides of leaves is needed for good control because the action is by smothering of the mites. Soap can cause phytotoxicity if applied under sunny hot conditions. Soap is a good alternative in conventional fields that are too close to harvest to use a true miticide; insecticidal soap has a 12-hour re-entry interval and a 0-day pre-harvest interval.

-Celeste Welty, Extension Entomologist

Table 1: Details about miticide choices

Table 2: Miticides for key vegetable crops

Table 3: Miticides for key fruit crops and hops

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.

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.

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