Wayne County IPM Notes from August 16 – August 22

Wayne County IPM Notes

(From the Week of August 16 – August 22)

Frank Becker, OSU Extension Wayne County

Vegetable Pests

Stink bugs have started to feed on and damage crops such as tomatoes. The stink bugs activity and feeding starts to increase most noticeably from late July through August and they remain active through the end of the growing season. Their damage on green tomatoes may appear as small, whitish areas. On ripe tomatoes, the damage shows up as a golden yellow “starburst” pattern. While this damage is typically only cosmetic, higher amounts of feeding can result in infection and result in the fruit being unmarketable.

Flea beetles feeding on young, fall planted, cole crops. F. Becker photo

Flea beetles continue to feed on several crops including tomatoes and cole crops. The feeding on tomato plants is not of major concern mostly because the damage I am seeing is on the lower leaves. The damage on cole crops is of more concern due to the areas of the plants being damaged. The flea beetles are feeding on young tender leaves on kale plants as well as causing heavy damage on young plantings of broccoli and cabbage. Too much damage at this point can stunt the plants growth and result in reduced yield.

The trap counts for sweet corn pests in Wayne County are overall down. Sweet corn growers should be keeping an eye out for army worm damage as we have had reports of high fall army worm trap counts as well as damage that was being done by the yellow striped army worm. More on recent trap counts

Vegetable Diseases

            Downy Mildew is in Wayne and Medina counties and likely in surrounding counties as well. Cucumber growers need to be spraying for downy mildew.

Powdery mildew can be just as destructive on squash as downy mildew is on cucumbers. I have been finding powdery mildew consistently in younger squash plantings. Unfortunately, the earlier the plant is infected with powdery mildew, the shorter the life span of the plant. With an infected plant having a short life span, the yield for the plant can also be expected to decrease.

Smut is especially prevalent on sweet corn this year. Smut is more common during hot and dry weather, especially when followed by a heavy, warm rain. This year has been the perfect year for prime smut infection and growth.

In some pepper fields, there has been a few spots of anthracnose found on the fruit. Anthracnose typically does not affect the pepper foliage; however, the pepper fruits are highly susceptible to infection from the disease. Peppers develop large sunken lesions with pink to orange colored spores. This disease can be found typically on the lower sets of fruit, where they are more likely to be splashed with soil from heavy rains.

Fruit Pests

Spotted wing drosophila have been active in small fruits for some time, but with peaches starting to ripen, the SWD can and will target the peaches as well. I have started to find peaches that have SWD larva feeding just under the skin.

SWD can also do damage to grapes. This week I started to find berries in grape clusters that were soft or looked poorly. Just under the skin of these grapes I found SWD larva feeding and moving around. Many grapes are ripening and getting close to harvest so anyone with grapes should consider treating for SWD.

Brown marmorated stink bug trap with adults and nymphs present. F. Becker photo.

Stink bugs can also do a lot of damage to fruit crops this time of year. We have traps out for the brown marmorated stink bug, which will help us monitor its population, however, I am already finding some stink bug damage on peaches and apples. This damage appears as a discolored depression in the skin with corking of the flesh all the way up to the skin. This damage can occur anywhere on the apple.

Fruit Diseases

            Overall, disease pressure has been fairly limited this year. Hot and dry conditions have prevented favorable conditions needed for disease development. As fruit continues to ripen and be harvested, we continue to move forward through the growing season without many disease issues in our area.

Some grape varieties are nearing harvest. At this point, there should be no significant disease concerns, especially so close to harvest. The same goes for orchard crops.

If you are doing any final treatments for fruit diseases, pay close attention to the PHI on the product label. The pre-harvest interval determines how long after you applied that product that you may harvest the crop. This is especially important to pay attention to as many varieties of orchard crops as well as grapes are maturing and nearing harvest.

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