There are three different European corn borer (ECB) areas in southwestern Ontario – a 1-generation (univoltine) area, a 2-generation (bivoltine) area, and an overlap area that has both univoltine and bivoltine populations (Baute, 1999). Degree Days (DD) are heat accumulations using a base temperature (i.e. a minimum temperature required for development). A DD model was developed to predict flight patterns of ECB in southwestern Ontario (Baute, 1999). This model gives us an idea when ECB flight begins, peaks and ends based on moth captures and can be used to guide scouting efforts and management decisions. Below are the estimated accumulated DD for ECB in some regions of southwestern Ontario.
Essex & Chatham-Kent Areas (2-generation/bivoltine area): As of Monday, June 5, DD accumulations were approximately 242 in Harrow, 269 in Windsor, and 218 in Ridgetown. Peak flight of the 1st generation is approaching, and will likely begin within the next week or two, depending on temperatures. Populations will continue to increase until peak flight. Start planning for ECB monitoring by getting your black light traps or pheromone traps ready and training your scouts for signs of larval entry holes in the peppers.
London & Sarnia Areas (overlap area): As of June 5, the DD accumulations were approximately 220 in London, and 191 in Sarnia. For the 2-generation population, first flight of the 1st generation has begun in these areas, depending on temperatures. Populations will continue to increase until peak flight. Start planning for ECB monitoring by getting your black light traps ready and training your scouts for signs of larval entry holes in the peppers. First flight of the 1-generation population is likely a couple weeks away.
Vineland Area (1-generation/univoltine area): As of June 5, the DD accumulations were approximately 186. First flight is likely a couple weeks away. Start planning for ECB monitoring by getting your black light traps ready and training your scouts for signs of larval entry holes in the peppers.
N.B. Warm, calm evenings are best for flight which usually begins shortly after sundown and ceases by midnight. High winds, thunderstorms and temperatures less than 180C (650F) can delay or stop egg-laying outdoors. Also, grassy areas or areas of dense vegetation are best for mating activities which usually begins by 10 p.m., peaks at 1 a.m., and ends at dawn. So please remember to clear the areas around the greenhouse of grass and other vegetation.
For more information on monitoring for ECB: https://ongreenhousevegetables.ca/2023/05/29/targeted-scouting-efforts-for-european-corn-borer/