Corn Leaf Aphid In Seedling Corn

JACKSON, TENN.

   This is the most common aphid found in corn, but treatment is rarely needed. A number of people have noticed that many aphids appear to be dead or dying. This is not surprising given that all field corn seed is treated with Cruiser (thiamethoxam) or Poncho (clothianidin), both of which are systemic insecticides that have activity on aphids. Treatment for corn leaf aphids would only be recommended in cases were there were obvious effects on the plant including wilting or dying leaves. This rarely happens and would typically require dozens, maybe hundreds of aphids on a seedling.

   Although aphids will migrate into fields, it is likely that some are coming from weedy grasses that were in the field at the time of emergence. The weather is a contributing factor because it delayed timely burndown applications. These same fields may be at risk to cutworms infestations for the same reason, so be alert for this pest. A pyrethroid insecticide at standard use rates would be the standard treatment for either pest. Δ

DR. SCOTT STEWART: IPM Extension Specialist, University of Tennessee

Corn leaf aphid

Photo courtesy of Iowa State University