Western bean cutworm (WBC) is an ear-feeder of corn, but the adults begin to emerge in late June. The number of adults caught in traps give us an indication of when to scout for eggs (note: it is NOT a measurement of economic threshold). Usually peak flight occurs anytime between the 2nd to 4th week of July, and, based on the spring temperatures, we seem to be headed in that direction. Trapping is done using a simple lure and either an empty milk jug (with 4 windows cut on the sides, and filled with 4 parts water: 1 part environmentally safe antifreeze, see figure) or a “bucket trap.” Traps and lures can be bought at IPM supply stores. Traps are placed on the edge of a corn field, and monitored at least weekly.
Once again, OSU-Extension will be running traps in Ohio cornfields across the state, and will publish weekly maps at the Agronomic Crops Insect webpage (http://entomology.osu.edu/ag/). Here, you will find other western bean cutworm information including past years’ maps, fact sheet and identification guides. Additional information can be found in the October 2010 issue of the Journal of Integrated Pest Management (http://www.entsoc.org/Pubs/Periodicals/jipm), a free journal designed to provide detailed pest information. We have a fair amount of late planted corn, which may be at risk for damage. Further updates will be provided over the summer.