David Owens, Extension Entomologist, owensd@udel.edu
Pumpkins
Scout pumpkins for aphids and treat if honeydew is starting to become evident, particularly on the pumpkin. We have a plethora of aphid active materials, including acetamiprid, Sivanto, Fulfill, PQZ, Sefina, Torac, diamides and Beleaf.
Spinach
Scout for beet webworms. I have not seen as many this year in lima bean fields, but they are present. They will lay eggs in spinach, beets, chard and pigweed. Controlling pigweed may help reduce a field’s attractiveness. Beet armyworm is also present and also prefers pigweeds. Both caterpillars will produce webbing as early instars, although webworms will fold leaves over themselves as later instars. It is important to differentiate the two species because beet armyworm are resistant to pyrethroids. Webworm larvae are narrow, translucent green with many dark spots. They will wriggle violently when pulled out of their shelters. Beet armyworm are a dull green and have a small black spot above their second pair of legs behind the head.
Sweet Corn
Periodically over the course of the season we have mentioned a Needs Assessment Survey for sweet corn in support of research prioritization and grant funding. We need your help to identify research needs and demonstrate need and interest in applied research for addressing earworm management. Our most recent mode of action is almost 20 years old, and earworm resistance to pyrethroids has made spray schedules and rotations a bit more of a challenge. Other questions regarding trapping efficacy and relationship to damage during the course of the season have come up among researchers. These are just some of the issues we have observed, but we need your feedback. Please take a few minutes to participate in this anonymous survey: https://ume.qualtrics.com/jfe/form/SV_9vRh1xHnDp4KEaa. Thank you!
Under current lower temperature conditions, it takes earworm eggs 3 days to hatch, meaning that we can relax spray schedules a bit on newly silking corn. Earworm catch in pheromone traps has decreased a bit over the past week. Thursday trap captures are as follows:
| Trap Location | BLT – CEW | Pheromone CEW |
| 3 nights total catch | ||
| Dover | 3 | 144 |
| Harrington | 1 | 64 |
| Milford | 1 | 87 |
| Rising Sun | 1 | 109 |
| Wyoming | 2 | 51 |
| Bridgeville | 2 | 63 |
| Concord | 4 | 67 |
| Georgetown | 1 | 94 |
| Greenwood | 1 | 59 |
| Laurel | 6 | 97 |
| Seaford | 4 | — |
| Lewes | — | 111 |
| Millsboro | 4 | 14 |