field edges do something similar, providing natural corridors, shelters, and floral resources for pollinators and the enemies of insect pests. “All the studies show the more diversity we apply to the landscape, the better off we are,” says Baute. “Anything we can do to benefit natural enemies [of pests], but also reduce greenhouse gasses, drought scenarios, making resilience in the soil and reducing erosion will benefit us greatly in providing that natural enemy habitat and make us a lot less prone to the pest itself…But we are also going to see maybe modifying our planting or harvesting dates, maybe planting varieties that are more genetically resistant. Even trap cropping … and implementing some biocontrol tools and biopesticides.” • 25 ONTARIO GRAIN FARMER AUGUST 2024 Western bean cutworm offers a current example of a pest which, thanks to seemingly small changes in climactic conditions, successfully made its way to Ontario after a century of stasis in the American Midwest. snow.” Though not a species being actively monitored in Ontario, Baute says, “the problem with this pest is we tend to walk away; we’re done scouting by November, but that’s when they’re doing the most damage.” With more days during which winter cutworm can thrive late in the season, the challenge of controlling them with chemicals on unfavourable terrain and in cool temperatures is concerning. SWEDE MIDGE: What happens in the case of Swede midge is a toss-up, with its range and population being dependent on moisture. It may expand well into Quebec, the Maritimes, and more parts of Western Canada with more moisture. ADDITIONAL CONSIDERATIONS If climactic changes affect insect pests, they also affect beneficial species, pollinators, and crop growth. For example, Baute says plants like soybeans will grow more quickly with higher atmospheric carbon dioxide. In the process, those soybeans become less nutritious to pest species, meaning those pest species will eat more. Soybeans will also become more susceptible to damage and pathogens as higher carbon dioxide levels suppress Jasmonic acid — one of the crop’s natural protections. Warmer winters could mean alfalfa weevil might outpace beneficial insects which parasitize it, rendering a key biological control less effective. Elevated growing season temperatures mean corn borer is less discriminate in its reproductive cycle, making it harder to track different races. Finding adequate spray windows may become more challenging as severe precipitation or heat events increase. Additionally, hotter temperatures mean insect metabolisms will run higher, potentially making some species less susceptible to current controls. THE PATH FORWARD No silver bullet exists for insect pest management. For Baute, the solution to any significant change in Ontario’s pest pressures lies in more resilient integrated pest management strategies, with diversity playing a critical role. She says that better and more diverse crop genetics and control products will help. Cover cropping and companion cropping, too, have been shown to support beneficial insect species effectively. In wheat, for example, a meta-analysis of 50 field studies showed wheat intercropped with one species of legume, brassica, or cotton generally decreased pests. Habitats along BEAN LEAF BEETLE (PHOTO: FRANK PEAIRS, COLORADO STATE UNIVERSITY, BUGWOOD.ORG). WESTERN BEAN CUTWORM (PHOTO: ADAM SISSON, IOWA STATE UNIVERSITY, BUGWOOD.ORG).
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