Cutworm numbers are rising, but not causing any problems

WOOSTER, Ohio — The number of adult moths of the western bean cutworm trapped by Ohio State University Extension professionals increased for the fifth straight year, but fortunately, larval infestations have yet to present an economic impact on Ohio farms.

“It’s definitely increasing, there’s no doubt about that,” said Extension entomologist Ron Hammond at the Ohio Agricultural Research and Development Center. “We caught about 1,000 more moths than we caught last year.”

Purpose

Hammond said OSU researchers and Extension educators trap adult moths across the state in an effort to track the spread and growth of the cutworm population in Ohio.

Traps caught 3,751 moths this year, compared with 2,695 recorded in 2010. The northwestern and northeastern regions of the state saw the largest increases in trapped adults.

“We spend a lot of time searching for larval infestations,” Hammond said. “As with the previous years, we found very few egg masses, and very little larvae. The bottom line is we did not have the kind of populations we are expecting to see sooner or later.”

Reason

Hammond said the low level of cutworm pressure exhibited in Ohio cornfields this year is likely due, in part, to the extreme heat during the peak flight, which this year occurred in the third week of July.

He said the state has not yet proven the most hospitable geography for the cutworm to infest.

“You have to get really far into the northwest before you get into the sandy soil types the western bean cutworm prefers,” Hammond said. “There are a lot of variables that enter into it, and so far, be it weather, soil type, or overwintering conditions, we’re just not seeing any problems yet.”

Nonetheless, he said farmers should remain aware of the potential for the cutworm to reach a threshold that could, someday, cause concern. He and his fellow researchers will continue monitoring, scouting and trapping the insect throughout its lifecycle and the growing season.

Advice

Despite the continually increasing number of adult moths trapped by Ohio State entomologists and Extension professionals, Hammond said the basic recommendations for dealing with the western bean cutworm have not changed.

In essence, farmers don’t need to do any preventive maintenance at this point.

“We realize a lot of growers are already planting BT hybrids for various reasons, but we don’t think one of those reasons needs to be the western bean cutworm,” he said. “You don’t need to go to a variety specifically to control the cutworm because it just isn’t needed at this time.”