Non-native insects in agriculture: strategies to manage the economic and environmental impact of wheat midge, Sitodiplosis mosellana, in Saskatchewan

Wheat midge, Sitodiplosis mosellana (Géhin) (Diptera: Cecidomyiidae), was first detected as early as 1901 in western Canada. The first major outbreak in Saskatchewan was recorded in 1983. Today wheat midge infests much of the wheat-growing area of Manitoba, Saskatchewan and North Dakota (USA), and is beginning to invade Alberta and Montana (USA). In 1984, Saskatchewan wheat midge populations were found to be parasitized by the egg-larval parasitoid, Macroglenes penetrans (Kirby) (Hymenoptera). Through the successful implementation of conservation techniques, this parasitoid now controls an average of 31.5% of the wheat midge across Saskatchewan. Estimated value of the parasitoid, due to reduction in insecticide costs in Saskatchewan alone, was estimated to be in excess of $248.3 million in the 1990s. The environmental benefits of not having to apply this amount of chemical insecticide are a bonus. To minimize the economic and ecological impact of S. mosellana today, wheat producers in western Canada have access to one of the most comprehensive management programs of any insect pest of field crops. Forecasts and risk warnings, monitoring tools, cultural control, agronomic practices, chemical control, biological control and plant resistance are all available for producers to manage wheat midge.