As insects go, black cutworm is one of the most despicable. There’s nothing quite like being able to row corn one day and finding it mown down the next.
Trap counts, weather conditions and the abundance of annual weeds are adding up to be a banner year for this yield robber. Agronomists in states across the Corn Belt are reporting intensive moth trap counts of black cutworm. Corn growers are being advised to be scouting emerging corn seedlings for signs of leaf feeding and cutting. Increased levels of moth flights are often the first sign of heavy egg-laying and possible infections from newly hatched larvae.
Syngenta agronomist Bruce Battles says no-till fields with annual weeds could be particularly susceptible. "Unfortunately, weather patters across the Cron Belt this winter and spring have created field conditions in which black cutworm populations tend to proliferate."
He says infestations have been known to reduce stands by more than 70% in some sections of fields. Syngenta agronomists recommend scouting by checking 20 plants in five locations every 25 to 30 acres. If the total damaged plants exceed 2% and larvae are smaller than three-fourths of an inch in length, consider treating with an insecticide. As larvae and corn increase in size, the threshold can rise, but less than optimum stands may require the lower threshold figure. Check state extension recommendations to get customized.
Battle notes that Syngenta’s Agrisure Viptera 3111 trait stack is designed to protect against black cutworm. Other trait stacks that contain Herculex I and Herculex Xtra also offer black cutworm control.
Black cutworm can be found from southern Canada throughout the United States and is known to feed on a wide range of field and garden crops.