WATERLOO, NY — Western Bean Cutworm (WBC) has decimated field corn, sweet corn and dry bean crops in New York since 2009. Mike Hunter, regional field crops specialist with Cornell University Cooperative Extension, recently presented “Managing Western Bean Cutworm” at the annual Corn Congress.
Hunter is part of the Northern New York Regional Ag Team.
The WBC is both migratory and overwintering in New York. Egg development takes five to seven days, leaving producers a small window of time to spray for WBC. That’s why understanding the WBC’s preferences makes all the difference in effectively combating it.
Hunter said the WBC prefers pre-tassel corn and usually hides on the upper side of the leaf. Multiple larvae can affect each ear and one larvae found on a plant can result in up to 50 to 60 percent damage of an ear’s kernels. Plus, indirect damage can include ear rot, fungal disease, and potential mycotoxins.
Since 2015, Hunter and other Cornell researchers have been studying the WBC because of increasing numbers of reports of Herculex and Smarstax Bt corn in Ontario, Michigan, Ohio and Indiana failing to adequately control WBC.
“We’re getting a big increase of the New York WBC trapped,” Hunter said. “We’re all of a sudden had increased trap counts.”
The research team planted large trial fields of corn on the host farms to offer a variety of growing conditions, such as soil types and rainfall, as well as planting dates.
In 2015, Researchers placed WBC traps on 31 farms in Jefferson, Franklin, Lewis and Erie counties. The insects trapped ranged up to 1,688 in Jefferson with an average of 524 WBCs.
In 2016, 32 traps in the same counties yielded an average of 388 WBCs. In addition, most affected samples exhibited fusarium ear rot, and others presented giberella ear rot, rhizopus ear rot, pennicilium ear rot, trichoderma, and cladosporium.
He added that because all indicators show the WBC is on the rise, producers must be more vigilant over their fields. He encouraged farmers to learn from the research team’s findings.
He said the trap counts don’t correlate with the amount of WBC damage.
“Our lowest trap count of 190 moths still had 18 percent damaged ears,” Hunter said.
He also learned that the dry season isn’t a favorable condition for WBC, which could have explained the reduced numbers in 2016 compared with 2015. But some farmers in the study said their land received average rainfall.
“Early planting date is likely to reduce WBC infestations,” Hunter said. “At these damage levels, WBC is not likely to reduce corn yields.”
Hunter didn’t think many WBCs over winter in fields.
“But they can over winter in the right soil, which is sandy soil,” Hunter added.
Mike Stanyard, specialist with Northwest New York Dairy, Livestock & Field Crops of Cornell Cooperative Extension, said that he has observed egg masses in Seneca County soil.
“They are difficult to find,” Hunter said, “and the five to seven-days window to spray is a small window. Planning the planting date early is a good strategy for us.”
Cornell Cooperative Extension, North West New York Dairy, Livestock & Field Crops team hosts the annual Corn Congress.