First Evidence of Western Bean Cutworm (Lepidoptera: Noctuidae) Overwintering in the Province of Québec (Canada)

Abstract

The western bean cutworm, Striacosta albicosta (Smith), is considered a major corn pest in North America. In 2009, it started invading the province of Québec (northeastern Canada). To our knowledge, there has been no evidence that this pest could overwinter in this province. In the falls of 2017 and 2018, storage totes containing mature western bean cutworm larvae were placed in the soil in three agricultural regions, in Québec, where western bean cutworm invasions are frequent and crop damage is often significant. The goal was to evaluate if western bean cutworm could resist the province's winter conditions. The storage totes were removed from the soil at different dates to estimate winter survival. Emergence cages were installed over the totes in the spring of the following year to determine whether western bean cutworm could complete its life cycle. In the spring of 2019, car shelters were also installed at two different sites to evaluate natural moth emergences in fields in which numerous mature western bean cutworm larvae and damage were reported in 2018. Western bean cutworm moth emergences occurred in both cases. These experiments constitute the first documented evidence that western bean cutworm can overwinter and complete its life cycle in Québec's cold climate. It also represents the northernmost overwintering survival for this species ever documented in North America. The western bean cutworm's ability to overwinter in Québec will have important implications for corn producers. Pest monitoring and management programs in the province of Québec will need to be adapted accordingly.

Keywords: cold climate; corn; sandy soil; survival; winter.