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.

The warm weather is upon us! We will see DD’s accumulate more quickly with the increase in temperature.

Essex & Chatham-Kent Areas (2-generation/bivoltine area):  As of yesterday, May 22, 2023 DD accumulations were approximately 133 in Harrow, 145 in Windsor, and 115 in Ridgetown. ECB flight of the 1^st generation may begin within the next couple of days in Harrow and Windsor, and within a week or two in Ridgetown, 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 May 22, the DD accumulations were approximately 112 in London, and 112 in Sarnia. For the 2-generation population, first flight of the 1^st generation will likely begin within the next week or two 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.   

Vineland Area (1-generation/univoltine area):  As of May 22, the DD accumulations were approximately 101. First flight is likely a few 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.