What's killing your corn borers?

Corn borer killed by the fungus Beauveria.

It has been a banner year for European corn borers and most of us have seen more this summer than during the past several years. Fortunately, every corn borer that hatches doesn't survive to tunnel into the stalk. Newly hatched larvae can be blown off the leaves by winds, knocked down by heavy rainfall, or dehydrated from hot weather before they find a place to hide in the whorl. Larvae also can be killed by several diseases, such as Beauveria, which causes a white fungal growth on the dead larvae, or Nosema, which also kills corn borers, but the symptoms of this disease can only be confirmed in a laboratory. If you find dead corn borer larvae and want to know whether a pathogen might have killed the insects, Les Lewis, USDA research entomologist, is willing to examine specimens mailed to him. Place them in a bottle, with or without alcohol, and send them to Dr. Les Lewis, USDA-ARS Corn Insect Research Unit, Insectary Building, Iowa State University, Ames, IA 50011.

This article originally appeared on page 137 of the IC-476(19) -- July 22, 1996 issue.

Updated 07/21/1996 - 1:00pm