David Owens, Extension Entomologist, owensd@udel.edu
Melons
Cucumber beetles are working their way out, spider mites are working their way in. Scout crown leaves, particularly near field edges. Recommended thresholds are 20-30% of crowns infested with 1-2 mites per leaf. In dry weather, mite populations can quickly ramp up, thus weekly scouting, particularly along field edges and in-field obstacles is recommended. Miticides are either contact or translaminar. Translaminar miticide active ingredients are abamectin, acequinocyl, and etoxazole. DO NOT tank mix these with protectant fungicides, especially chlorothalonil. If a field is starting to get mites and bees have not yet been placed, abamectin containing products would be an excellent choice.
Squash and Zucchini
Right on cue, last weekend I found squash vine borer. Now is the time to begin taking proactive protective measures. Row covers can be used until plants begin flowering. The vegetable recommendation guide lists 4 weekly pyrethroid applications but also notes that applications of Coragen or a Spinosyn (Radiant, Entrust, Blackhawk) will suppress vine borer. What these latter two compounds will not control are squash bug. I have been seeing more Anasa species in melons. Scout for egg masses underneath leaves. Egg masses of squash bug are coppery colored and typically laid between leaf veins. The threshold is 1 egg mass per plant. You may need to treat twice, as eggs are impervious to insecticides.
Potato
Continue scouting for Colorado potato beetle and potato leafhopper, ESPECIALLY if your potato field is near alfalfa that is soon to be or has just been cut. When alfalfa is cut, the adult potato leafhopper is driven out of the crop and will settle on nearby crops. Treat if leafhopper adults exceed 1 per sweep or 1 nymph per 10 leaves.
Sweet Corn
Earworm counts appear to be down a bit from recent peaks. A big thank you to Dick Monaco and to DDA SCBGP FB 22-04 for maintaining traps and providing financial support.
Thursday trap counts are as follows:
| Location | Blacklight Trap | Pheromone Trap |
| Dover | 1 | 39 |
| Harrington | 0 | 33 |
| Milford | 1 | 34 |
| Rising Sun | 0 | 2 |
| Wyoming | 3 | 56 |
| Bridgeville | 0 | 4 |
| Concord | 0 | 22 |
| Georgetown | 1 | 2 |
| Greenwood | 0 | 7 |
| Laurel | 1 | 53 |
| Lewes | — | 4 |
| Milton | — | 83 (6 days) |
| Whaleyville | — | 38 |
Snap Bean
Consider treatment for bean leaf beetle and corn earworm. We have had a moderate flight the last couple of weeks which may result in earworm eggs being laid in flowering snap bean. I suspect a single application between flowering and pin pod should keep them out.