Vegetable Insect Scouting

David Owens, Extension Entomologist; owensd@udel.edu

Pumpkins
Continue scouting for aphids, squash bugs, and cucumber beetles in pumpkins that could scar rinds. Aphid populations across Delmarva have been very high for several species. Melon aphids can transmit viruses to pumpkins and large populations can coat pumpkins with honeydew which allows for sooty mold growth. Scout also for evidence of lepidopteran rind worms. Beet armyworm has been especially active in Georgetown this year on pigweed, it may move over into other crops. Earlier this season we encountered a beet armyworm population that was resistant to chlorantraniliprole. For cucumber beetles, remember Assail or Harvanta are your best options.

Cole Crops
Recently transplanted cole crops have low worm thresholds. Look for windowpaning and small holes on leaves. Fields with weeds in them may also have climbing cutworm and yellow striped armyworm, and beet armyworm is widely active. When treating cole crops, include a spreader type adjuvant.

Tomatoes
The late tomatoes at the research station have both loopers and beet armyworm. Worm identification is important, as both are resistant to pyrethroids and loopers are only partially removed by diamide applications.

Edamame
Scout for podworm and stink bug in edamame, much of which was fairly late planted. The stink bug threshold is 7 per 50 sweeps (this is less than half the regular soybean threshold). The mid-Atlantic vegetable guide suggests fairly frequent worm sprays once pods have started forming

Peppers
Continue scouting for beet armyworm, populations remain high in pigweed. If pyrethroids have been used in the crop, scout also for green peach aphid.

Spinach
We have seen more Hawaiian beet webworm this year than last, but not nearly as many as 2023. Pyrethroids are not recommended for webworm or beet armyworm. Other groups include spinosyns, Proclaim, Bt, insect growth regulators, Avaunt, and diamides.

Lima Bean
Continue scouting for podworm and loopers in lima bean. Not only were populations high last week for both pests, but flowering lima bean are also highly attractive to moths. Thresholds are 1 CEW per 6 row feet.

Sweet Corn
Corn earworm populations are a fair bit lower in Thursday’s trap  count compared to last week but remain plenty high in the blacklights to maintain a tight 2–3-day spray schedule, depending on material used, silking progress, and temperatures. If within the first week of silking, or temperatures above 82, or using a pyrethroid/lanate tank mix, a 2-day spray schedule may be best. If following a Besiege or Elevest, I think a 3 day should suffice.