Authored by: Dr. Art Schaafsma and Dr. Jocelyn Smith, University of Guelph Ridgetown Campus and Tracey Baute, Ontario Ministry of Agriculture, Food and Rural Affairs

As the planting season begins, it is important to consider how best to manage western bean cutworm (WBC) damage this year and reduce the risk of resistance development.

Western bean cutworm has become a serious pest of corn in Eastern Canada resulting in yield loss and contamination of grain by mycotoxins. Only two main tools are now available to manage WBC: foliar insecticides and Vip3A transgenic corn.

With so few WBC management options, resistance to these tools is a real concern. In Ontario, WBC quickly developed resistance to the Cry1F Bt protein found in Herculex and SmartStax hybrids. Herbicide tolerant weeds in Ontario are a good reminder of the importance of resistance management.

The key to resistance management for WBC is rotation of management tools whether they are insecticidal or transgenic (Bt) modes of action.

Information on how to manage mycotoxins and reduce the risk of WBC resistance to insecticides or Viptera Bt corn hybrids can be found at: Resistance Prevention – Managing Western Bean Cutworm and Mycotoxins in Corn (a PDF file).