PESTS AND DISEASES Resistance is rising for the neonicotinoid insecticides that are the primary weapon against this pest. What are the alternatives? BATTLING COLORADO POTATO BEETLE E by Mark Halsall ver since becoming widely used in Canada in the late 1990s, neonicotinoid pesticides have helped keep Colorado potato beetle (CPB) populations in check. But the pest could be poised for a comeback, due to growing CPB resistance to neonics and the prospect of the Group 4 insecticides being banned from Canadian potato farms. Heath Canada’s Pest Management Regulatory Agency (PMRA) proposed a ban on imidacloprid (the first neonicotinoid to be registered for CPB control) in November 2016, and plans to release a final decision in December of this year on whether to phase out the popular pesticide used to control insect pests in a wide range of crops. The PMRA has also reviewed the use of two other neonic products, thiamethoxam and clothianidin, and proposed a ban for some crops, while limiting its uses on others. The final decision is also expected to be released in December 2018, according to the government of Canada’s website. Ian Scott, a research scientist with Agriculture and Agri-Food Canada (AAFC) based in London, Ont., says the loss of neonicotinoid chemicals would be deeply felt. “It definitely would have an impact on potato pest management. [It’s] been a very valuable class of insecticides to potato growers, so anytime you lose something like that there’s going to be impact until other solutions are found,” he says. TOP: Colorado potato beetle egg mass. Colorado potato beetle adults feeding in the field. BOTTOM: TOP CROP MANAGER/POTATOES IN CANADA | Spring 2018 5 PHOTOS COURTESY OF TRACY SHINNERS-CARNELLEY.