Swede midge, a pest that can damage brassicaceae crops, was first identified in Ontario in 2000.

“This insect can be a real challenge to manage,” said Hannah Fraser, provincial entomologist for horticulture crops at the Ontario Ministry of Agriculture, Food and Rural Affairs (OMAFRA). “Research conducted by Dr. Rebecca Hallett at the University of Guelph indicates that they can have four to five overlapping generations over the growing season.”

Coragen will fit into an Integrated Resistance Management (IRM) system because it is powered by the active ingredient Rynaxypyr, which comes from a whole new class of chemistry – Group 28, the diamides.

The tiny, light-brown adult swede midge is hard to differentiate from other midges; and the larvae are even harder to scout. According to OMAFRA, swede midge larvae are initially 0.3 mm long and transparent, typically feeding in groups near the growing point. According to Fraser, damage from swede midge can be confused with other common problems in crucifer crops; therefore, when swede midge first showed up in Ontario, it was not immediately recognized.  

Low levels of damage can rapidly become a large problem if the population is left unmanaged. Without a good Integrated Pest Management (IPM) program that involves regular monitoring, growers could lose the entire crop to swede midge.

“Growers must follow OMAFRA guidelines, monitor each field and spray early,” says Saghir Alam, development specialist with DuPont Canada. “Swede midge is not like other pests, such as cabbage looper or diamondback moth, where if you miss spraying one instar you can get them when they’re bigger. In this case, it’s very difficult to see the pest and by the time you see damage, it’s too late.”

OMAFRA recommends using commercially available pheromone lures and white Jackson-style traps to help track the emergence and activity patterns of the pest, as well as to determine the need and timing of insecticide sprays.

More information about Coragen is available at www.coragen.ca.