David Owens, Extension Entomologist; owensd@udel.edu
Sweet Corn
Continue scouting fields for fall armyworm whorl infestations. Corn earworm trap counts are beginning their annual climb from a somewhat low period during the last half of July. In several locations, blacklight traps are indicating for a more conservative spray schedule than pheromone traps. This could be due to crop phenology near our pheromone traps.
Sweet corn pheromone and blacklight traps are checked twice weekly on Mondays and Thursdays. By Tuesday and Friday morning, data is uploaded to our website https://agdev.anr.udel.edu/trap/trap.php. Moth counts from Thursday are as follows:
| Trap Location | BLT – CEW | Pheromone CEW |
| 3 nights total catch | ||
| Dover | 5 | 65 |
| Harrington | 1 | 4 |
| Milford | 4 | 23 |
| Rising Sun | 6 | 16 |
| Wyoming | 3 | 21 |
| Bridgeville | 2 | 53 |
| Concord | 4 | 36 |
| Georgetown | 5 | 15 |
| Greenwood | 0 | |
| Laurel | 64 | |
| Seaford | 3 | 34 |
| Trap Pond | 3 | 12 |
| Lewes | 7 | 168 |
Watermelon
Spider mites and cucumber beetles have needed treatment in some fields recently. Continue scouting for them. As a reminder, action thresholds increase to 50% of terminal leaves infested. When scouting, examine mites under magnification to make sure that they are alive and active. Dead mites frequently turn a brownish-gray dull color. Several miticides have a long preharvest interval (7 days). Portal and Acramite are 3 day PHIs and Kanemite is a 1 day PHI.