Joanne Whalen, Extension IPM Specialist;jwhalen@udel.edu
Melons
Continue to scout all melons for aphids, cucumber beetles, and spider mites. Be sure to read all labels carefully for rates and restrictions since some materials, especially miticides, are restricted to only one application as well as ground application only.
Lima Beans
Be sure to scout fields for leafhoppers, spider mites, plant bugs and stink bugs. As soon as pin pods are present, be sure to watch carefully for plant bug and stinkbug adults and nymphs. As a general guideline, treatment should be considered if you find 15 adults and/or nymphs per 50 sweeps. The higher rates of labeled products will be needed if stinkbugs are the predominant insect present.
Peppers
Depending on local corn borer trap catches, sprays should be applied on a 7 to 10-day schedule once pepper fruit is ¼ – ½ inch in diameter. Be sure to check local moth catches in your area by calling the Crop Pest Hotline (302-831-8851) or visit our website at http://agdev.anr.udel.edu/trap/trap.php . At this time, you will also need to consider a treatment for pepper maggot. The first beet armyworms (BAW) have also been detected – chemical selection is important once this insect is found in peppers. Be sure to select a material that also has BAW control on the label.
Potatoes
Continue to scout fields for Colorado potato beetle, leafhoppers, and aphids. Controls will be needed for green peach aphids if you find 2 aphids per leaf during bloom and 4 aphids per leaf post bloom. This threshold increases to 10 per leaf at 2 weeks from vine death/kill. If melon aphids are found, the threshold should be reduced by half.
Snap Beans
Continue to sample all seedling stage fields for leafhopper and thrips activity. As a general guideline, corn borer sprays are needed at the bud and pin stages on processing beans. Additional sprays may be needed after the pin spray on processing beans for corn borer and corn earworm. Since trap catches can change quickly, be sure to check our website for the most recent trap catches and information on how to use this information to make a treatment decision in processing snap beans after bloom.
After the pin spray on processing beans, the spray schedule will be determined by a combination of both moth catches and field scouting.
http://agdev.anr.udel.edu/trap/trap.php
Sweet Corn
Continue to sample all fields through pre-tassel stage for whorl feeders (corn borer, corn earworm and fall armyworm). A treatment should be applied if 12- 15% of the plants are infested with larvae (regardless of the species). The predominant whorl feeder being found at this time is the fall armyworm. Since fall armyworm (FAW) feed deep in the whorls, sprays should be directed into the whorls and multiple applications are often needed to achieve control. FAW can also be a problem in silk stage sweet corn, especially in outbreak years. The first silk sprays will be needed for corn earworm as soon as ear shanks are visible. Be sure to check both blacklight and pheromone trap catches since the spray schedules can quickly change. Trap catches are generally updated on Tuesday and Friday mornings on our website (http://agdev.anr.udel.edu/trap/trap.php) and the Crop Pest Hotline (302-831-8851). Information on scouting sweet corn and how to use the trap catch information can be found at http://extension.udel.edu/ag/insect-management/insect-trapping-program/action-thresholds-for-silk-stage-sweet-corn/.