Wayne County IPM Notes From the Week of June 13-17, 2022

Agronomic Crops

We certainly got our fair share of rain the in last few weeks, but we have also seen a significant increase in temperature just in the last week. Given the warmer weather, slugs may feed on young corn and soybean plants at night and early in the morning but will likely retreat to the soil or under crop residue during the day. The black cutworm was still active in corn, although as some of the corn fields we are scouting are approaching V7, the feeding has not been as severe as compared to some fields that are VE through V3. Black cutworms are much less likely to cut plants at the V4 stage and beyond. Many of the soybean fields in the area are beginning to emerge. We are typically seeing plant maturity anywhere from sprouts to VC (unrolled unifoliolate leaves). We are beginning to find some potato leaf hoppers in the alfalfa. Remember that the best way to scout and check for leaf hopper populations is to use a sweep net. The threshold for potato leaf hoppers is based on the alfalfa height in inches and the number of leaf hoppers per 10 sweeps. If you have more leafhoppers in 10 sweeps than the height of the alfalfa, then you are over threshold.

 

Vegetable Crops

The Colorado Potato Beetle larvae have hatched and are now 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.

In summer squash/zucchini, we are seeing an increase in the number of cucumber beetles. The seed treatment on these plants is beginning to wear off. For fall vine crops that have just been planted in the last few weeks, that seed treatment should still have a few weeks of efficacy left.

In onions, we have noticed an increase in the number of thrips, in many cases approaching an action threshold. Threshold is 25-30 thrips per plant. This week we also found more incidences of slippery skin which was confirmed by the vegetable pathology lab at OARDC earlier this month. Slippery skin is caused by Pseudomonas gladioli. This bacterium is spread via soil splashing from heavy rains and enters the plant through natural openings or openings from mechanical injury. Given the heavy rains we have experienced in the past week, it would probably be a good idea to get out and check your onions.

Overall, tomatoes are continuing to grow rapidly in the greater Wayne County area, with some plantings of field tomatoes beginning to set blooms. We did have a case of timber rot identified in the West Salem area in field tomato. It is important to practice good crop rotations and rotate out of a crop family completely for at least 3-4 years. A complete crop rotation will help to break up disease and pest cycles. Similar to onions, tomatoes can contract bacterial diseases from soil splashing. If you have tomatoes, it may be worthwhile checking the lower canopy of your plants to monitor the presence of any diseases.

Our IPM pest scouts have continued to find Mexican bean leaf beetles in the green beans this week. Light foliar feeding was observed.

With the warmer weather and plants maturing rapidly, the slug threat has greatly reduced in the last week. Any new transplants should still be monitored for feeding, however there should be less of a slug presence for the rest of the growing season.

 

Small Fruit and Orchards

This week we continued to find aphids in apple trees. Our IPM program identified populations of green apple aphids in several orchards as well as a case of wooly apple aphids. Both aphid species can cause significant damage at this time of year. Accordingly, diligent scouting is a crucial aspect to not allowing either of these aphid species from getting out of hand. The heavy rains likely knocked back some of these aphid populations, but it will be important to monitor aphid populations as the weather dries out a bit.

In apples, we continued to so find a few instances of fire blight. Conditions have been ideal for fire blight development, so it is not much of a surprise to see some cases.

We have had sustained catches (over threshold) of both Codling Moth and Oriental Fruit Moth in apple and peach orchards, respectively. Over the last week, both Codling Moth and Oriental Fruit Moth populations have been trending downward, however, numbers have still exceeded the action thresholds.

With the storms over the course of the last week, it is not unlikely that we will see some yield loss from wind, heavy rains, or hail damage in many of the area’s fruit trees.

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 buckshot berry stage. It is still possible to spray for and manage black rot during this time.

Sign-Up Info for the 2022 IPM Scouting Season

The enrollment period for the 2022 Wayne County IPM scouting program is now open. Please call the Wayne County OSU Extension Office at 330-264-8722 if you are interested in signing up or for more information about the program. Enrollment forms are being sent in the mail to previous program participants.

More information about the IPM program and details on how to enroll may be found here: 2022 IPM Forms

Wayne County IPM Notes from the Week of August 9 – 13

Agronomic Crops

There was a significant reduction in potato leaf hopper counts this week. This drop is likely due to timely cutting in the fields we scout, along with frequent heavy rains. When wetter weather, or with days that have heavier morning dews occur, potato leafhoppers can diminish quickly due to the entomopathogenic fungi that can cause the population to collapse. When these conditions occur, and populations of potato leafhoppers drop, there is no need to treat.

Field corn is pushing R3-R4, as the silk is now drying down all the way to the kernel and the kernel is filling out and the ears start into maturity. In soybean, pods are developing all of the way up the plant, and pods are starting to fill. As pod fill begins to occur, it is a critical time to be watching for insects like stink bugs that would be damaging the pods and developing seeds.

Vegetable Crops

Squash vine borer damaged plants.

This week brought about many sightings of squash vine borer larva. The adult squash vine borer moths were actively flying and lay eggs about a month ago. We are now seeing plants that are declining in health and when inspected further, are oozing frass and have stems that look shredded. When we split the stem of these plants, in nearly every instance, we found at least one, if not several squash vine borer larvae. Unfortunately, there is nothing that can be done to reverse such severe damage.

A large squash vine borer found feeding in a pumpkin plant.

Flea beetles are feeding on young cabbage and broccoli, and the cabbage worm butterflies are finding their way into these plantings as well. We are starting to see some damage in peppers from the European corn borer and expect the ECB and CEW numbers in the traps to increase in the next week or so.

Small Fruit and Orchards

As apples and peaches are harvested, do not let your guard down on the late season generations of codling moth and oriental fruit moth. This past week was another week of rising codling moth numbers, and consistent oriental fruit moth catches, although the oriental fruit moth numbers have not gone back over threshold.

Grapes damaged by grape berry moth larvae.

Grapes are starting to ripen, and as the season progresses, we are still finding consistent trap catches of grape berry moth. Although it may be too late for some varieties, you may still be able to protect later maturing varieties with a treatment for grape berry moth.

Wayne County IPM Notes from the Week of August 2 – August 6

Agronomic Crops

All of the corn that we are scouting is now at least R1. It is important to keep an eye out for pests like Japanese beetles or northern corn rootworm beetles that can cause damage to the crop by feeding on and clipping the silks. Clipped silks can significantly reduce the amount of successful pollination.

Soybeans are starting into pod development. At this time of year, insect pests like stink bugs and bean leaf beetles can cause pod and seed damage, which directly impacts yields. The forecasted hot and dry weather will be favorable for large populations of spider mites showing up in fields.

This is an important time of year to have adequate moisture, for corn, soybeans, and alfalfa. Corn and soybeans need adequate moisture for complete ear and pod fill, respectively. After recent cuttings, alfalfa fields are slow to put on significant regrowth, which can lead to concerns with potato leaf hopper feeding.

Vegetable Crops

We are still continuing to find new infections of downy mildew, and increasingly more frequent in younger plantings of cucumbers. It is highly recommended to treat your cucumbers for downy mildew, especially in plantings where harvest is not expected to start for several more weeks.

Powdery mildew is slowly but surely spreading onto more area pumpkin patches and squash plantings. If you have plantings of squash that you are done picking in, it would be best to terminate these plantings to reduce the amount of inoculum that is present, especially if younger plants are nearby.

A lot of area growers are still struggling with bacterial diseases in tomatoes and peppers and root rots like pythium and phytophthora in pepper plantings. The warm and damp conditions that we experienced during July are partially to blame for rapid onset of many of these diseases. Hot and dry weather, however, can help to slow the spread of bacterial diseases.

Small Fruit and Orchards

We are finding Spotted Wing Drosophila in the traps that we have set out in peach blocks. While peaches are not a preferred host for SWD, some damaged and infested fruit can still occur. To the best of your ability as a grower, it’s a good practice to pick frequently and keep the ground around the trees clean. Culled fruit provides a food source and suitable habitat for many pests and diseases and removing the cull fruit can help prevent or reduce the severity of issues. Codling moth counts continued to increase this week. Oriental fruit moth counts in our traps continued to decline. In grapes, we are finding consistent catches of the grape berry moth.

Wayne County IPM Notes from the Week of July 19 – 23

Agronomic Crops

Rapid crop growth and development is a common sight around the area in corn and soybean fields. The majority of corn fields have tasseled

Alfalfa field in bloom.

and are beginning to silk. Soybeans are flowering and pod development is starting to occur.

We are beginning to find some foliar diseases affecting corn fields, as well as the continuation of insect damage from flea beetles, grasshoppers, armyworm, and several other pests. Soybeans are still being fed on by a wide variety of foliar pests. Our focus will start to shift to pod feeding pest, such as stink bugs and bean leaf beetles. Read more on Corn and Soybean management decisions.

Potato leaf hoppers are remaining consistent in population in alfalfa fields. We are seeing populations either at or below threshold. Some fields have cases of leaf spot; however, we are not seeing any fields with any severe infections at this time.

Vegetable Crops

Powdery mildew found on a cucurbit plant in a Wayne County field.

The Vegetable Pathology Lab at OARDC has confirmed several more cases of downy mildew, on both cucumbers and cantaloupe. It is important to take steps to either protect your crop or stop the spread of any ongoing infections. Powdery mildew is also spreading rapidly through the area. Although some heavy rains may have slowed its spread, favorable conditions have led to some fields rapidly becoming infected.

Flea beetles feeding on young green cabbage plants.

Bacterial diseases continue to spread in pepper and tomato plantings. Pay close attention to these crops in particular, and make sure that you are taking the necessary precautions so as to not spread bacterial diseases. Bacteria can be spread from plant to plant via clothing, equipment, or animals. More from APS

Flea beetles are feeding heavily on recently planted cole crops, which left uncontrolled can cause stunted and underperforming plants. Another insect we have seen quite a few of is the squash vine borer. Although these are not typically going to harm large numbers of plants, they can still be a nuisance, especially in smaller plantings.

Small Fruit and Orchards

 This week we found our first incidence of scab in apples. While this was only an isolated find on a few leaves, it is a good reminder to take some time to scout your apple trees and look for any signs of scab. Oriental fruit moth numbers were significantly above threshold again this week. Japanese beetles were also

Severe damage from Japanese beetles feeding on the foliage of apple trees.

still feeding heavily in many of the fruit crops we scout. Spotted wing drosophila are still being found in all of our traps, and for anyone with small fruit in the area, it is recommended that you treat for SWD.

Wayne County IPM Notes from the Week of July 12th – July 16th

Agronomic Crops

Crop development progressed rapidly in the last week with the abundance of moisture and warm temperatures. Corn plants are either tasseling or nearly there, soybeans have started to flower and overall, there was a lot of new growth.

European Corn Borer and Armyworm found feeding in field corn. The ECB was found feeding on this tassel that has yet to emerge.

Japanese beetles continue to feed in corn, soybeans, and alfalfa. Stink bugs are also out in corn and soybeans, although, stink bugs are more damaging later in the season during ear and pod development, respectively. We are also finding an uptick in worm damage in corn, from both the European Corn Borer and Armyworm.

Potato Leaf Hopper counts were at or below threshold this week. Considering that many alfalfa fields are starting into bloom, we anticipate that fields will be cut before our PLH counts would go over threshold.

Vegetable Crops

Of most importance, the Vegetable Pathology Lab in Wooster confirmed Downy Mildew on a cucumber plot at OARDC. Cucumber growers are highly encouraged to begin taking action to protect their plants, especially as more cases are confirmed around the area.

Japanese beetles are out in force this year and continue to be one of the most consistent insect pests from week to week on a wide range of crops. Other insect pests of note included Colorado Potato Beetles that have migrated off of harvested potato plantings in into tomato and eggplant plantings. In squash, we have still been finding quite a few squash bug egg masses. Squash Vine Borers have also been spotted in some area pumpkin plantings.

Colorado Potato Beetles feeding on a tomato plant. Tommy Becker photo.

During these heavy rains, we have noticed a significant amount of soil splashed up onto the plants and fruit. This will likely encourage more disease incidence. Accordingly, take extra time and care to scout your crops in the coming weeks.

Sweet corn pests like corn ear worm and European corn borer are not showing much activity in our traps. We occasionally find damaged tassels from ECB feeding, however, we have yet to have any fields go over the 10% damage threshold.

Small Fruit and Orchards

 Between last week and this week, we have seen a sustained flight of oriental fruit moth in area peach blocks as our traps have been well over threshold for the last two weeks. Our codling moth traps still do not show much activity.

Over ripe Lodi apple that had spilt following a heavy rain.

We did find some interesting things while scouting apples this week, including blister spot on some “Delicious” apple varieties and Lodi apples that had burst and fell off the trees due to being over ripe.

As a note for all small fruit growers, all of our traps for SWD in the area are currently catching SWD, therefore, we recommend you treat your small fruit. Pay close attention to the label, especially the REI (re-entry interval) and PHI (pre-harvest interval). Another note for all fruit crops, Japanese beetles are feeding on grapes, apples, peaches, and blueberries. The beetles can do significant defoliation as well as damage to the fruit.

 

Wayne County IPM Notes for the Week of July 5 – July 9

Agronomic Crops

             Potato leaf hopper counts seem to be remaining constant, staying below threshold in alfalfa fields. Other insects, such as Japanese beetles in sweet corn, or grasshoppers in soybeans, are not holding steady, instead, we are seeing increasing population numbers and an increase in foliar feeding activity. Corn fields have seen an uptick in activity and feeding from armyworm.

In some fields, where moisture seemed to be limited due to spotty rain showers, we have started to see some nutrient deficiencies, more specifically potassium. Adequate soil moisture is key to have nutrient uptake through mass flow, and when nutrients like potassium are not taken up in adequate amounts, the effects of lack of moisture can compound.

Vegetable Crops

             High tunnel tomatoes were one of the areas of focus for disease development this past week. Many high tunnel tomatoes are currently experiencing cases of leaf mold. As a side note on high tunnel tomatoes, we did observe a thrips outbreak in a high tunnel, where heavy feeding by the thrips was causing significant discoloration on the foliage and stunting of the plants. Peppers took up the other focus with disease development, mainly due to favorable conditions for bacterial diseases to manifest.

Flea beetles seemed to make a comeback this week. Several fields of cole crops were over threshold for flea beetle counts. Japanese beetles are continuing to feed in the majority of the crops planted in the area. Other insects like squash bugs are starting to be found more frequently, specifically in early planted summer squash.

Sticking with cucurbits, we are starting to find spots of powdery mildew in plantings of zucchini and yellow squash. It is important to scout your crops and look for powdery mildew, especially if you have succession plantings of young cucurbit crops nearby. Powdery mildew is easily spread onto younger plants, so it is recommended that you keep up with spraying for powdery mildew and terminate the older infected plantings once you are done harvesting.

Small Fruit and Orchards

 First and foremost, we have found spotted winged drosophila in our area. The threshold for SWD in small fruit is 1 fly. Since we are now finding adults, we encourage growers to also do salt tests on the berries to check for larvae.

Wooly apple aphids continue to show up in the several apple orchards in the area. These are a tough pest to get under control due to their protective waxy coating.

OFM counts in some peach blocks were above threshold for the first time in several weeks. OFM counts remained well below threshold.

Wayne County IPM Notes From the Week of June 21-25

Agronomic Crops

            This week was a good week for crop growth and development. We are now seeing V6 to V8 corn and soybeans reaching V2-V3 in most

Northern Corn Leaf Blight lesion on a corn leaf.

areas. As the crops continue to progress, they become more tolerant of early insect pests like cutworms and slugs. Overall, there are not many concerns with our agronomic crops at this point in the season. We are, however, starting to see the arrival of some more common summer pests.

Japanese beetles have started to make their presence known in corn and soybean fields across the area. We are also finding an increasing number of grasshoppers, especially in soybean fields. This week we also noted our first sighting of Northern Corn Leaf Blight.

In alfalfa, we have not observed any large counts of potato leaf hoppers to this point. There are a few out there, but nothing has been over threshold so far.

Imported cabbage worm eggs in the red circles and a recently hatched caterpillar circled in yellow.

Vegetable Crops

            Imported cabbage worm butterflies are laying a lot of eggs on cole crops. It is important to scout the crops for the eggs as well as the larvae, in order to have a better grasp on when the larvae are hatching and causing damage. This will also help ensure efficient and timely insecticide applications.

Aphids are continuing to be present in many of the vegetable crops that our IPM program scouts,

Thrips feeding in on onion leaves in the center of the plant.

however, we are finding a lot of beneficial insects that are feeding on the aphids and helping to either maintain or eliminate populations. Japanese beetles also are present now in many of the crops in our area.

This week was also the first week that we really noticed an increase in thrips in onion plants. As the leaves get larger and offer more shelter for the thrips, the populations are able to multiply rapidly.

Some sweet corn in the area is tasseling, silking and in some cases, nearing harvest. We have noted some European Corn Borer feeding in tassels. If 10% of silking plants are damaged by ECB, a treatment is warranted. In some fields, this threshold was met, and growers started on a spray program for their tasseling and silking corn.

Small Fruit and Orchards

Aphids in the apple trees continued to be the main pest this week. We found more clusters of wooly apple aphids, which are now working their way out onto the new shoots and green growth. Our trap counts for OFM remain well below threshold.

OFM traps in peach blocks were also well below threshold, however, we did see an increase in the trap counts of Greater and Lesser Peach Tree Borer.

Strawberry season is winding down. Our SWD traps in strawberry patches yielded 0 SWD. Harvest is starting in some area blueberry and bramble patches. Grape clusters are developing nicely and starting to put on some size.

Wayne County IPM Notes From the Week of June 7-11

Agronomic Crops

            Corn and soybeans are both being impacted by slug feeding. In most cases, corn will be able to outgrow the pressure from the slug feeding. Soybeans, however, are much more susceptible to being severely damaged by slug feeding, even to the point of significant crop loss. Slugs are best managed by avoidance and habitat reduction. Slugs thrive in heavy residue fields with minimal tillage disturbance. Later planting dates, when soils start to dry out, along with some tillage or residue management can help to prevent major impacts from slug feeding.

Black cutworm, Matthew Nussbaum photo.

Some corn fields are also being impacted by black cutworms. These caterpillars can do significant damage in young corn stands. We are reaching the end of their feeding activity in our area, but we will continue to monitor for other larva pests. Weed management is also important this time of year in agronomic crops. Being able to knock the weeds back until we start to get some canopy closure can help prevent the weeds from competing with corn or soybean plants for water, nutrients, and sunlight.

Alfalfa fields are showing good regrowth with minimal pressure from diseases or insect pests. There are some concerns with increasing aphid populations, along with the arrival of the potato leaf hoppers.

Vegetable Crops

            The insect pressure on the area vegetable crops has continued without much fluctuation.  In summary, the Colorado potato beetle larvae, along with flea beetles, continue to feed on potatoes, tomatoes and eggplant, we began to find tortoise-shell beetle feeding on the leaves of sweet potatoes, thrips are starting to feed in onions, aphids are continuing to feed in many crops, including peppers and tomatoes, slugs are feeding on sweetcorn, as are cutworms, cucumber beetles are all over cucurbit crops, and potato

Golden Tortoise Beetle on Sweet Potato.

leaf hoppers and bean leaf beetles have started to build population in green beans.

The warm and wet weather has led to some disease concerns, especially in lettuce. We have started to find heads of lettuce being affected by white mold. It is best to remove these heads of lettuce from the field to prevent further infection and soil infestation.

Small Fruit and Orchards

Our trap counts for CM and OFM were either 0, or low this week, with none of our trapping locations being near threshold. Most of the small fruit in our area is in fruit development, or fruit maturity. Strawberry harvest is fully underway at this time. We are seeing some slug feeding on strawberries, but very few other concerns at this time. Grapes are beginning to bloom, and depending on the variety, may already be in full bloom. Don’t forget to spray for black rot during this period.

Wayne County IPM Notes from the Week of June 1- June 4

Agronomic Crops

Emerging soybeans in a no-till field.

Corn and soybeans are emerging and beginning to progress through early vegetative stages. Within the next week or so we will begin doing stand counts and encourage you to do the same. We will also keep an eye out for early season insect and pest problems such as slug damage and bean leaf beetle feeding in soybeans as well as slug feeding, cut worm damage and flea beetle activity in field corn.

In alfalfa most of the fields we are scouting are now in regrowth after first cutting. These second cutting fields have very limited pressure from weevil larvae and overall are relatively problem free. In the coming weeks, we need to be alert with regard to the potato leaf hopper. According to the most recent C.O.R.N. newsletter, potato leaf hoppers are now being found in Ohio alfalfa fields. We plan on starting with sweep net counts this week to determine current populations of PLH in our area fields.

Vegetable Crops

Cucumber beetle feeding on the foliage of a summer squash plant.

Insects continue to be the main headline in the vegetable crops in our area. Of greatest concern is the cucumber beetle. The populations continue to increase in number and the efficacy of seed treatments or in-furrow applied insecticide starts to decline 4-6 weeks after the seed germinates or after the insecticide is applied. This means that more of the beetles are feeding without being affected by the insecticide. Be sure to scout cucurbit crops frequently and carefully to get accurate counts of the beetles. The thresholds for cucumber beetles are as follows: Cotyledon stage – .5 beetles per plant, 2-4 leaf stage – 1 beetle per plant, greater than 4 leaves – 3 beetles per plant. Limiting the amount of feeding that cucumber beetles do will also limit the amount of bacterial wilt occurring in these plantings. Do be cognizant of the plants that are in bloom and limit your spraying to a time when it will be least impactful on the pollinators.

 

Colorado potato beetle larva feeding on a potato plant. Tommy Becker photo.

Other insects that were spotted this week include Colorado Potato Beetle larvae and imported cabbage worms. Both of these pests can cause significant damage in their respective crops when left unchecked. Flea beetles also continue to feed on plantings of cole crops, preferring young transplants versus older, more established plantings, although both should be inspected for beetles.

Sweet corn plantings are growing quickly and some plantings that were done into plastic mulch and covered this spring already have a few tassels poking out. Overall, there has been no major concerns in the sweet corn plantings so far, however, do your best to keep up on weed control. Weeds such as bindweed, thistle, and ragweed can not only compete for resources, but can also make harvest difficult and may serve as refuge locations for insect pests to retreat to.

Small Fruit and Orchards

We are beginning to enter a critical period for managing diseases in grapes. This period, which extends from immediate pre-bloom through four to five weeks post bloom, is a critical time to control fruit infections by the pathogens which cause black rot, powdery mildew, and downy mildew. According to the 2021-2022 Midwest Fruit Pest Management Guide, the fruit of the most commonly planted varieties becomes resistant to infection by these diseases by four to five weeks after bloom.

In strawberry plantings we are seeing a lot of green fruit and in some locations, harvest is beginning to ramp up. Overall, there have been very few concerns in the

Blueberries starting to enter the “fruit coloring” stage.

strawberries to this point, with just a few slugs here and there and a spotting of powdery mildew on a few plants. Powdery mildew is managed by spraying either pre-bloom or during the early bloom through bloom stage.

Other small fruit like blueberries and brambles look to have a heavy fruit set this year. Blueberries are beginning to get some color to them, and the blackberry and raspberries are either in bloom or in fruit development.

In apple and peach orchards, the fruit are noticeably starting to increase in size. We are finding some aphids in apple trees, feeding on the leaves and new shoots. In peaches, we did find a few instances of powdery mildew affecting the fruit. Trap counts for OFM and CM were under threshold in all of our traps this week. The counts are down after last week with several orchards above threshold for CM and OFM counts.