Whitish-gray caterpillar with small black spots on body and shiny black head. Fron 1/8 - 1" long.

Feeds on leaves in whorl of corn, then bores into stalk when half-grown. Survival reduced in corn under 6-leaf stage.

Incidence:

Late June into early July; wherever corn is grown in Nebraska

Examine at least 25 corn plants in each of 4 locations in the field. Note the percent of total plant whorls with feeding damage; unroll several damaged whorls, record number of live worms per plant. Note size of worms.

Economic Threshold:

Depends on price of corn, yield potential, cost of application, and number of larvae, 3 - 5% loss per borer that reaches maturity per plant. See worksheet at the entomology web site http://www.unl.edu/entomology/

More Information and Treatment Recommendations:

http://www.unl.edu/entomology/extension/crops/fieldcorn.shtml