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 validated 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 Wednesday, July 12, DD accumulations were approximately 587 in Harrow, 632 in Windsor, and 528 in Ridgetown. First flight of the 2nd generation will likely begin in the next week or two in these areas, depending on temperatures. It will be a couple of weeks before we see the peak of the 2nd generation flight. This peak tends to be greater than the first. Be sure to monitor for ECB by getting your black light traps or pheromone traps set up and train your scouts for signs of larval entry holes in the peppers.
London & Sarnia Areas (overlap area): As of July 12, the DD accumulations were approximately 526 in London, and 485 in Sarnia. For the 2-generation population, peak flight of the 1st generation has ended, however, flight will still continue once peak flight has ended. First flight of the 2nd generation will begin in the next couple of weeks in these areas, depending on temperatures. It will be a few weeks before we see the peak of the 2nd generation flight. This peak tends to be greater than the first. First flight of the 1-generation population is underway. Peak flight of this population will likely begin within the next week or two, depending on temperatures. Be sure to monitor for ECB by getting your black light traps or pheromone traps set up and train your scouts for signs of larval entry holes in the peppers.
Vineland Area (1-generation/univoltine area): As of July 12, the DD accumulations were approximately 519. First flight is underway. Peak flight of this population will likely begin within the next week or two, depending on temperatures. Be sure to monitor for ECB by getting your black light traps or pheromone traps set up and train 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 pheromone trap catches, the Great Lakes and Maritimes Pest Monitoring Network is a helpful resource (look under moth counts): here
For more information on monitoring for ECB: here