Since western bean cutworm is a relatively new pest for Ohio corn growers, there may still be some
misinformation regarding its biology and impact. Dr. Andy Michel, OSU Extension entomologist, has
monitored this new pest since its first occurrence in Ohio.
One myth is that economic damage from western bean cutworm has occurred in Ohio.
To our knowledge, we have yet to see a situation where western bean cutworm control was necessary. The
first larva we found was in Putnam County in 2009. This was the only one found that year. In 2010, we
did find eggs and larvae in a few counties.
Some of these fields had damaged ears from WBC, but none were at the economic threshold. Remember,
economic threshold is 5 percent of plants infested with eggs or larvae after inspection of 20 plants in
five different areas of your field.
So when can Ohio expect economic damage? Based on situations in our neighboring states and Ontario, it
may be soon. Economic damage has been seen in Indiana since 2007, Michigan in 2008 and Ontario since
2010. Typically, some damage was found before economic damage occurred.
This indicates that for Ohio, we could see, or even expect, economic situations within the next few
years. However, because we cannot predict where economic damage will occur, planting Bt hybrids for the
sole purpose of WBC control may not provide a good return on investment.
In comparison, adult trapping costs about $6 for the whole season. This is a good return on investment
considering the valuable scouting information obtained. Monitoring for adult flight and good egg and
larvae scouting remains the best tactic to manage WBC.
Wood County western bean cutworm trapping conducted by this columnist, first detected adult moths in
2008. In 2009, a total of 49 moths were trapped in Wood County among 3 trap locations.
In 2010, these same trap locations yielded 271 moths, a significant increase in moth numbers. However,
economic damage of larvae feeding on corn ears has not been found in Wood County.
Trapping will continue in 2011 to monitor this new pest. Farmers are encouraged to report to the
Extension office at (419) 354-9050 any unusual corn earworm damage.