Agronomic Crop Insect Scouting

David Owens, Extension Entomologist;

Corn earworm, stink bugs, and soybean loopers are the primary pests active in fields right now. Other insects present include green cloverworm, grasshoppers, and soybean aphids. Soybean aphids usually come in too late and in not enough numbers to cause any harm. Green cloverworm, grasshoppers, and soybean loopers are members of the defoliator complex. Defoliation thresholds are about 15% in reproductive stage soybean until we hit R6 – seeds touching each other in the pods in the upper canopy. Once this is achieved, plants can lose up to 50% of their leaves without significant yield loss. Grasshoppers and cloverworms are best controlled with a pyrethroid, if going after grasshoppers, higher rates are recommended. Soybean loopers are not affected by pyrethroids. If large numbers of loopers are present, consider a worm specific product such as Prevathon, Intrepid, or Steward. Stink bug thresholds are 5 bugs per 15 sweeps until R6.5.

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