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.
Greenhouses
Now that transplants are starting, scout greenhouses for signs of aphids and spider mites. Pay attention to any weeds growing underneath tables and near doorways.
Seedcorn Maggot
By the end of next week, first generation seedcorn maggot adults will begin emerging from the soil. Favorable conditions for SCM include organic matter, especially manure, incorporated within 3 weeks of planting, fields that are wet, and when cool weather is in the forecast. A seed treatment is highly recommended in these conditions.
Cole Crops
Cabbage is going in the ground and all the cute white butterflies are looking for them. Begin scouting for larval infestation. There is often very high mortality in cabbage white eggs. While a useful indicator of potential infestation, do not take any action on eggs by themselves.