To prevent disease problems with your corn, choose cultivars that tolerate or resist….

Common corn diseases. Rotate corn with other crops to prevent recurring pest and disease problems. If you've had problems in the past, you can apply parasitic nematodes to soil before planting to keep wireworms, seedcorn beetles, and other soil-dwelling pests in check. To help control earworms drop mineral oil into immature ears as soon as you see the pest.