Joanne Whalen, Extension IPM Specialist; jwhalen@udel.edu
Asparagus
Asparagus beetles adults can be found laying eggs and feeding on spears. As a general guideline, a treatment is recommended if 2% of the spears are infested with eggs. Since adults also feed on the spears, a treatment is recommended if 5% of the plants are infested with adults
Cabbage
Continue to scout for diamondback and imported cabbageworm larvae. A treatment should be applied when 5% of the plants are infested and before larvae move to the hearts of the plants.
Melons
As soon as plants are set in the field, be sure to scout for aphids and cucumber beetles. When sampling for aphids be sure to watch for beneficial insects as well since they can help to crash aphid populations. As a general guideline, a treatment should be applied for aphids when 20% of the plants are infested, with at least 5 aphids per leaf.
Potatoes
Low levels of the first emerged Colorado potato beetle adults can be found in fields where at-planting insecticides were not applied. A treatment should not be needed for adults until you find 25 beetles per 50 plants and defoliation has reached the 10% level.
Sweet Corn
Be sure to scout emerged fields for cutworms and flea beetles. As a general guideline, treatments should be applied for cutworms if you find 3% cut plants or 10% leaf feeding. In order to get an accurate estimate of flea beetle populations, fields should be scouted mid-day when beetles are active. A treatment will be needed if 5% of the plants are infested with beetles.