By Emily Zobel
Ag Agent Dorchester County
General Tips: Check > 50 plants throughout the whole field when making treatment decisions. Localized infestations can be spot treated to save time and money. For up-to-date chemical recommendations, check the Mid-Atlantic Commercial Vegetable Production Guide. Read all labels carefully for rates and restrictions.
Cucurbits: Continue to scout for aphids, cucumber beetles and spider mites. Early detection is critical since these pest populations can quickly explode during hot, dry weather. Watch for rind feeding pests such as beet armyworm, yellow-striped armyworm, cabbage loppers, and cucumber beetle adults in melon fields.
Sweet Corn: Sample pre-tassel stage for whorl feeders (corn borer, corn earworm, and fall armyworm). Treatment should be applied when 15% of plants are infested with larvae and should be directed into the whorls.
Lima Beans and Snap Beans: Scout fields for aphids, leafhoppers, and spider mites. The leafhopper threshold is an average of 5 per sweep. As soon as pin pods are present, check for plant bugs and stink bug adults and nymphs. As a general guideline, treatment should be considered if you find 15 adults and/or nymphs leafhopper per 50 sweeps. Continue to scout for bean leaf beetles and Mexican bean beetles—Control when there is an average of 20% defoliation or 1 beetle per plant.
Potatoes: 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.
