By John Tooker and Delbert G. Voight
Western bean cutworm (WBC) has been a confusing pest species for me and, perhaps, for corn growers in Pennsylvania. Moths of this species lay eggs in June, July, and August, and their caterpillars feed on reproductive tissue of corn, particularly the tassel and the developing ear. Historically, this pest species has been a challenge for corn growers in Nebraska and other western states, but in the early 2000s, it started to spread eastward.
Using pheromone traps, we first found WBC moths in Pennsylvania in 2009, and we then trapped for them annually from 2009 to 2015. We discontinued this effort in 2016 because, even though we were finding moths, we could not find significant populations of caterpillars in nearby corn fields. At the same time, populations of moths in other states (e.g., New York, Michigan, Ohio, Wisconsin) and provinces (Ontario) in the region were large, and entomologists in those areas were regularly encountering economic damage in corn and dry and snap beans.
During the summer of 2025, we restarted our trapping efforts for WBC to understand if their abundance had increased and to see if we could find infestations in fields. Extension educators trapped moths during July and August across ten counties, and we reported our data to the Great Lakes and Maritimes Pest Monitoring Network, which is operated by Ontario's Ministry of Agriculture, Food and Rural Affairs.
Source : psu.edu