Four weeks ago this column addressed black cutworms, an insect pest of corn favored by delayed planting and presence of weeds (especially winter annuals) prior to planting. It was noted that black cutworm moths had been caught in pheromone traps in several northern Illinois counties and that insect degree-days can be an effective tool to help determine when to start scouting for this pest.

Intense captures (nine or more moths captured in one or two days) were reported in these northern Illinois counties: Lee, Ogle, Stephenson, Whiteside, and Winnebago. The expected cutting date for these counties is NOW based on 300 degree-days accumulated from the date of the intense catch to May 28.

Priority fields to scout first would be first-year corn fields infested with winter annuals (common chickweed, etc.), especially where conservation tillage (including no-till) has been practiced.

If you find one percent of your corn seedlings have leaf feeding, this indicates that future damage from cutting is possible at economic levels (3 to 5 percent). Don't assume that Bt corn, insecticidal seed treatments, or the use of a soil insecticide at planting will eliminate damage from this pest.

Further information on black cutworms is available at this University of Illinois website: http://ipm.illinois.edu/fieldcrops/insects/black_cutworm/index.html , or contact your local University of Illinois Extension office.