Insect update: diamondback moths
Each spring, adult populations of diamondback moths ride wind currents northward from infested regions in the southern or western U.S.A. Once in the Canadian prairies, the moths can cause economic levels of feeding damage throughout the season, with much of their damage occurring when they feed on the exterior of developing pods.
To protect beneficial insects and make the best economic decisions, apply insecticide only if diamondback reach the economic threshold of 200-300 larvae/m2 (20-30/ft2, or approximately 2-3 larvae/plant) at late flowering or podding. For easier counting, pull up all plants from one square foot and beat them on a flat surface, such as a sheet or truck hood, to dislodge them. Because diamondback cycle rapidly (they can achieve three or four generations within the growing season), accurate and frequent scouting is critical. (Prairie Pest Monitoring Update: Week 11) (Diamondback moth economic threshold)
