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Tips for early-season scouting in corn and soybeans

Tips for early-season scouting in corn and soybeans

Regular scouting will be essential this growing season to control for those pests and diseases that can impact crop yields.

Because of mild winter temperatures this year, pests and diseases may have survived better. Therefore, regular scouting will be essential this growing season to control for those pests and diseases that can impact crop yields.

“Every year is a balancing act between good growth and vitality and early-season insects and pathogens,” says Scott Heuchlin, DuPont Pioneer research scientist, field pathology. “For growers who were able to start the season with a warm seedbed, good soil tilth and sunshine during emergence, the balance is shifted in favor of the plant. The biggest challenge will be for seeds that were planted into less-than-ideal seedbeds, creating stress for plants and making them vulnerable to pests and diseases.”

Which pests should you scout for?


  • Black cutworm
  • Corn rootworm


  • Bean leaf beetle
  • Soybean aphids
  • Brown marmorated stinkbugs

Black cutworm Spring storms prior to tillage and planting provided favorable conditions for this pest. Corn plants are most vulnerable up to the V4 stage and susceptible up to the V6 stage.

Recommendations for management:

  • Monitor flight reports, scout fields and incorporate tillage.
  • Consider a rescue treatment if plants are small, cutworms are active and economic thresholds are exceeded.
  • Broadcast pesticide or bait application may be used as a rescue treatment.

Corn rootworm Cool spring conditions throughout the Corn Belt have delayed expected timing of rootworm hatch. To protect corn from rootworm damage, experts encourage multiple management strategies. Those include:

  • Routine scouting and trait evaluation throughout growing season
  • Checking fields for larval corn rootworm injury
  • Scouting for adult corn rootworms, especially in corn-on-corn production

Overall, the most effective management strategy for corn rootworm is to incorporate a crop rotation that alternates corn with other crops. If continuing with corn, consider a dual mode of action in corn rootworm resistant traits, especially if you’ve used the same one for several years.

Bean leaf beetle Soybean plants are particularly vulnerable up to the two-leaf stage. There is also potential for later generations of the bean leaf beetle to come in and feed directly on the pods. To manage for this pest, you should scout and monitor fields early. Insecticide seed treatments are generally effective in reducing damage from overwintering pests. However, you may need to spray to combat later-season threats.

Soybean aphids While soybean aphids were not a major problem last year and were limited to northern states, aphid populations can rebound significantly after low years. Natural predators, such as lady beetles and insidious flower bugs, may help to suppress populations. It is a good idea to scout for the pest from late June through August.

Brown marmorated stinkbugs (BMSB) Pests continue to expand across the country, including every state east of the Mississippi and several western states. Locations near forested urban areas are at higher risk. Since the distasteful bugs have few natural enemies in North America, close scouting is essential, particularly around the field borders where bugs tend to feed.

Which diseases should you monitor?

Seed rot and damping off are two major risks if planting was rushed and seeds were planted into cold, wet soils. The best protection for the seed is fungicidal seed treatments. Because of late planting this year, seed treatments will help protect seed as soil temperatures warm up quickly and allow plants to get out of the ground.

Additional resources:

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