David Owens, Extension Entomologist, owensd@udel.edu
Sweet Corn
Scout for Fall armyworm. Whorl infestations have been reported in New Jersey. It is very important to catch above threshold populations early. Look for windowpaning on whorl leaves and small, light brown frass pellets. If an infestation is not caught early, worms will move deep into the whorl and be far more difficult to control. Also make sure that windowpaning is not being caused by spotted cucumber beetle.
Earworm trap counts are starting to tick upwards. With next week’s heat, you may want to consider tighten up spray schedules a day, especially following a pyrethroid application. Thursday trap captures are as follows:
| Trap Location | BLT – CEW | Pheromone CEW |
| 3 nights total catch | ||
| Dover | 0 | 6 |
| Harrington | 1 | 57 |
| Milford | 1 | 26 |
| Rising Sun | 1 | 41 |
| Wyoming | 0 | 14 |
| Bridgeville | 0 | 12 |
| Concord | 2 | 27 |
| Georgetown | 1 | 26 |
| Greenwood | 1 | 38 |
| Laurel | 1 | 8 |
| Seaford | 1 | — |
| Lewes | — |
27
|
Watermelon
In fields we have been scouting, spider mites have been slow to build up. However, reports of Lepidopteran rind feeders have been coming in. Cucumber beetles are also emerging from the soil. Scout for rind damage on melons paying attention to all surfaces. Cucumber beetles sometimes feed on the bottom half of the melon to stay out of sunlight during the heat of the day, resulting in melons that look like they have a bowl cut hair style. Cucumber beetle feeding looks dirty, while Lepidopteran feeding will look smooth. If you see Lep rind feeding, try to identify the worms present in the field. Last week we captured our first beet armyworm in pheromone traps. Beet armyworm are attracted to pigweeds; larvae are resistant to pyrethroids. Corn earworm will also damage rinds, and are partially resistant to pyrethroids. All other Leps should be controllable with all worm materials. If Leps are not a concern but cucumber beetles are, acetamiprid, cyclaniliprole, and carbaryl have performed well. All three are quite toxic to honeybees, and carbaryl can result in mite flare ups.
Reports of aphid pressure have also been received. Aphids can flare up after pyrethroid applications due to suppressed lady beetle activity. Multiple insecticides will control them, including Exirel, Harvanta, Minecto Pro, Assail and Torac. Aphid selective materials include Beleaf, Fulfill, PQZ, Sefina, and Sivanto. Scout for signs of beneficial insect activity. Parasitic wasps will transform
Drip Chemigation Rates
A few weeks ago we took some video footage of a drip insecticide application to discuss how to properly calculate rates. That is now available on YouTube, check it out: https://youtu.be/GaZlAFtBlNk .
Pepper
Scout for beet armyworm infestation. Beet armyworm eggs are laid in masses and early instar larvae feed in aggregate and make webbing, which can result in significant defoliation in localized areas. Beet armyworm are resistant to pyrethroids.
Spotted Lanternfly Quarantine
DDA has expanded the spotted lanternfly quarantine to the entire state. When moving equipment, plant material, packing material, firewood and any other equipment or supplies not stored indoors, check before leaving the state that no lanternflies are hitching a ride on it. At this time of the year they will be black with white spots or red with black and white spots. You can find more information about the quarantine and permitting from DDA’s website: https://agriculture.delaware.gov/plant-industries/spotted-lanternfly-quarantine/.