Western Bean Cutworm Moths Are Flying

Penn State Extension established the Western Bean Cutworm Monitoring Network again this year. This pest species has been present in Pennsylvania for at least three years now, but we have yet to receive any reports of infestations of caterpillars. Now, it seems that moth active has increased substantially from last year. Last year, we caught a total of 350 moths statewide; this year through 14 July we have collected about 600 moths in our pheromone traps. As a reminder, we have yet to document damage in Pennsylvania from western bean cutworm caterpillars, though last year we found a caterpillar in Centre County, so we are not exactly sure what to make of this higher number.

With these higher moth captures, it would seem the risk of finding damage is elevated and we have already received reports of suspected egg masses in corn fields. Please notify me if you encounter damage in the field. Key to the damage potential of this species will be the stage of the corn when the majority of eggs are being laid. Western bean cutworm caterpillars appear to prefer feeding on reproductive tissue of corn, so vegetative corn is not as attractive as more mature life stages. Nevertheless, according to colleagues at Ohio State, even in whorl stage, larvae can burrow through leaves and feed on the developing tassel.

It is a bit early to expect to see any damage from this species, but we will continue to track populations across Pennsylvania and will keep folks informed of our findings.  See our webpage for details on this pest and a summary of our trapping efforts for the past two years (http://ento.psu.edu/extension/field-crops/corn/western-bean-cutworm) and we will update this soon with numbers from this year.