David Owens, Extension Entomologist, owensd@udel.edu
Sweet Corn
Trap counts have declined a bit since last week at this time.
| Trap Location | BLT – CEW | Pheromone CEW |
| 3 nights total catch | ||
| Dover | 1 | 24 |
| Harrington | 0 | 12 |
| Milford | 0 | 17 |
| Rising Sun | 0 | 1 |
| Wyoming | 0 | 41 |
| Bridgeville | 0 | 1 |
| Concord | 1 | 15 |
| Georgetown | 0 | 17 |
| Greenwood | 0 | 10 |
| Laurel | 1 | 5 |
| Seaford | 1 | 0 |
Cucurbits
Continue scouting for spider mites and for aphids. Aphids have been observed in late planted fields that have not been treated for cucumber beetle. Spider mite populations have been observed along field edges, this week’s scouting indicates a slight decrease in mite numbers, but this may be due in part to some fields receiving treatment.
Scout zucchini, squash, and any winter squash that may be growing for squash vine borer and squash bug. The threshold for squash bug is 1 egg mass per leaf. Foliar treatments with pyrethroids or acetamiprid should be effective on squash bug. Please note that Assail does not have borer activity, but it will also work against aphids.
Potatoes
Scout potatoes for potato leafhopper. This is about the time in which leafhopper populations increase in our area. Thresholds are 1 adult per sweep or 1 nymph per 10 sweeps. Nymphs are very small and lime green.
Fruiting Vegetables
Continue scouting for spider mites and signs of worm activity, especially in tomato. While the corn earworm flight so far has been fairly low, corn earworm is not the only worm pest that will affect tomatoes. Spider mite thresholds are 2 mites per leaflet in tomato. If using an abamectin product, be sure to read the label carefully, as some require the use of adjuvants to prevent illegal product residue on the harvested produce.
Snap Beans
Scout snap beans for defoliation, potato leafhopper, and spider mites. Leafhopper thresholds are 5 per sweep. Pyrethroids, Lannate, neonics, and the more exotic group 9 materials are labeled for use on snaps. Be sure to select a product that won’t flare mites.