Reproductive biology and overwintering success of the Western Bean Cutworm

Principal Investigator

Jeremy McNeil

Research Institution

The University of Western Ontario

External Funding Partners

Ontario Bean Growers (applicant – Growing Forward 2)

This project was funded in part through Growing Forward 2 (GF2), a federal-provincial-territorial initiative. The Agricultural Adaptation Council assists in the delivery of GF2 in Ontario.

Project Start

April 2015

Project End

October 2017


  • Determine if both sexes of the Western bean cutworm (WBC) produce long distance sex pheromones.
  • Evaluate the effect of temperature/humidity on respiration of prepupae in the spring and fall.
  • Evaluate the effect of soil temperature/humidity on survival in field cages.


  • The enhancements to monitoring techniques which are better matched to the WBC biology and better reflect potential crop damage will allow corn farmers to manage crops more economically by using insect control products when threshold targets are reached.
  • The understanding of overwintering survival parameters will provide the basis for a model to predict the effect of abiotic conditions (such as climate) on the overwintering survival for different areas where the WBC is found.

Scientific Summary

Western bean cutworm (WBC; Striacosta albicosta) is an important agricultural pest of corn and edible dry beans. Historically the WBC has been limited to the western part of North America. However, in the last decade it has expanded its range and is now found in the Great Lakes region each summer. The sex pheromone had been identified and pheromone traps have been used as a monitoring tool. However, it was noted that trap catch data provide a very poor indicator of subsequent damage in either beans or corn. WBC injury has also been shown to increase incidence of fungal diseases in corn ears. Better management of the pest will not only reduce direct losses due to herbivory but reduce the potential for mycotoxins in the grain, particularly deoxynivalenol (DON).

This project investigates the gaps in understanding of reproductive and overwintering biology of WBC that should help explain the increased densities of this insect in Ontario. The objective of this study is twofold. First, to determine if both male and female moths produce a long distance sex pheromone. We will run traps baited with randomly chosen males and females from a light trap at Bothwell. And second, to examine the overwintering biology/physiology of western bean cutworm prepupae. We established a major field plot with 90 cages (about 1m in depth), some with probes at different depths so that we can monitor seasonal changes in temperature. This information will provide a data base for future models predicting year to year changes in the population density of local populations. The studies on prepupal mortality, together with our earlier results on cold hardiness, will provide a solid basis for the development of a model to predict the effect of abiotic conditions on the overwintering survival for different areas where the WBC is found. This will be integral to the development of a sound management strategy for this species, and allow for improved adherence to OMAFRA recommendations regarding action thresholds and use of integrated pest management strategies.