David Owens, Extension Entomologist, owensd@udel.edu
Asparagus
Scout for asparagus beetle adults and eggs on emerging spears. Eggs are small, cylindrical and dark colored. They stick into the spear at a 90-degree angle. Asparagus beetles have large white square shaped spots bordered by dark metallic blue bands. It can take a week for eggs to hatch. Feeding on spears results in scarring, browning, and hooked tips. Examine 10 plants in 5-10 different spots in a field, best on a warm, sunny afternoon when beetles are going to be most active. A treatment may be justified if 10% of spears are infested with beetles or 1-2% have eggs. Labeled products for spears include malathion, permethrin, and carbaryl.
Potatoes
With this week’s extremely warm weather, Colorado potato beetle should have been able to fly from volunteer emerging potato to new locations. If you have potato up and out of the ground, begin checking for CPB. Generally, seed piece treatment with a neonic or a diamide should provide an extended period of control, although data from VT’s Tom Kuhar suggests that we have lost quite a bit of residual control time compared to when the neonics were first developed, meaning the products will not be effective for quite as long as they once were.
Snap Beans
Seedcorn maggot adult activity will begin increasing again this week. With warm temperatures and relatively dry soil, the risk for heavy damage should be a bit lower, but this is a pest that is hard to predict. If planting into a tilled field (tilled within the last week or so), an insecticidal seed treatment is recommended.