b"Survival of theFITTESTAs insecticide resistance grows within the Colorado Potato Beetle population, you may be wondering how is this happening?BY: ASHLEY ROBINSONIT ONLY TAKES A FEWsurvivors to makeThe amount of individuals within the population something spreadwhich is how insecticidethat have the gene starts to magnify over time resistance is growing throughout the Colorado Potatoand contain a lot of nasty chemistry. To digest Beetle (CPB) population. You name me athese salads CPBs have detoxifying agents in Resistance really is survival of the fittest, Ianpesticide thatstheir bodies, which in some cases can also detoxify MacRae, an extension entomologist at the Universityinsecticides, MacRae says.of Minnesota, told the audience at the Ontario Potatoregistered to useThere are different resistance genes in CPBs Conference in Guelph, Ont. in March. Its aboutagainst Colorado Potatothough, MacRae says. There is metabolic, where who's around to have kids at the end of the day. CPBs are able to break down the insecticide inter-Insecticide resistance has been on the rise acrossBeetle and I will tell younally. Target site resistance is another way, where insect populations, but especially amongst CPBs, Mac- theres a populationinstead of the insecticide latching onto a nerve re-Rae says. You name me a pesticide that's registeredceptor, the receptor is shaped slightly differently and to use against Colorado Potato Beetle and I will tell yousomwhere that isdoesnt have space for the insecticide to clamp on.there's a population somewhere that is resistant to it.resistant to it.The most interesting resistance though is CPBs follow a similar life cycle each year. Theywhere CPBs have developed a genetically controlled will overwinter in old potato fields and emerge inIAN MACRAE behaviour to avoid insecticides, MacRae says. The the spring to find the nearest new potato field. TheyCPB will not emerge until after the neonic seed snack on the fresh crop and then drop down into thetreatment has broken down and the potato plant is soil to re-emerge later in the summer to feast again.left unprotected and ready for munching. Since the 1990s, growers have used neonicotinoidthe pests evolution to survive the targeting, MacRaeIncreasing resistance is really throwing us a seed treatments to protect their potato crops againstsays. Resistance is pre-adaptive, so it doesntwrench in our fight against CPBs, MacRae says. the first CPB infestation. As resistance grows though,matter how many insecticides are sprayed, the geneIt used to be we had two peaks of adults. One that CPBs are increasingly able to survive. is already there and will survive. Even if only one incame out in the spring and fed as larvae and then Insecticides are designed to target a specific partevery 1,000,000 CPBs have it, those insects will livedropped down and incubate, and then we see a later of the pest and kill themresistance comes fromon and reproduce. peak of adults. We don't see that anymore. 28 SPUDSMART.COM FALL 2020"