LEFT: Ian Scott (top left), Sophie Krolikowski and Vincent Atienza inspect a Colorado potato beetle sample at Agriculture and Agri-Food Canada’s London Research and Development Centre. where we had multiple classes of effective insecticides the recommendation would be simple. It would be ‘don’t use neonics, go and use another class of chemistry.’ But we just don’t have those one-for-one alternatives.” Scott is hopeful that more viable alternatives to neonicotinoids will eventually be developed. “I think the industry is very innovative in its approach to all aspects of potato production and pest management, and I know it’s always looking within Canada and outside for other solutions,” he says. Integrated pest management For now, Scott believes integrated pest management (IPM) is a grower’s best bet for CPB protection. A combination of chemical and cultural techniques, he says, will help slow resistance development and also prolong the effectiveness of current CPB insecticides. Scott points to crop scouting as important tool for potato farmers. “I think the more monitoring the growers can do, the earlier that they can diagnose a problem in the field before it gets out of hand,” he says. Scott recommends producers rotate chemical classes in season if possible and also try not spray insecticides too often, since this also kills predators that help keep CPB populations down by feeding on the insect’s eggs and the early stages of the beetle. Other non-chemical strategies for CPB control listed by Scott include crop rotation and varying the timing for planting potato crops. Scott notes that maintaining field borders can also help reduce the spread of CPB populations. He says buffer zones around potato fields can provide more habitat for CPB predators, and can also act as a physical barrier for the beetles. Shinners-Carnelley says IPM is always a good idea when it comes to insect control. But she cautions that some recommended practices such as buffer zones and crop rotation aren’t always practical when it comes to a bug like CPB, since it isn’t soilborne and can easily fly between fields. Shinners-Carnelley adds that when developing thresholds, different factors such as the number of beetles, the amount of defoliation, the type of potato variety, crop maturity and the length of season all need to be taken into account. “All these things are variable so one threshold is not going to apply to everything.” Field trials conducted during Shinners-Carnelley’s research study indicate that despite growing CPB tolerance to neonicotinoids, the chemicals still have an important place. “It goes against best practice but the recommendations I’ve been using based out of this this trial are that in the short-term, growers need to be using the highest labelled rate of the products so that they’re getting the longest duration of control,” she says. “We have very few other chemistries, so yes in an ideal world BREEDING TO DESTROY CBD C hemicals in the leaves of potato plants, produced naturally by the plant, may hold the key to a new way in controlling Colorado potato beetles. Agriculture and Agri-Food Canada (AAFC) research scien-tist, Helen Tai (pictured here) has turned to the leaves growing on wild potato rela-tives – leaves that Colorado potato beetles won’t eat – as a new approach to keep the pest away. Many plants in the potato family contain natural defence chemicals that protect plants against insects and patho-gens. Using mass spectrometry and other sophisticated tools, Tai was able to identify what’s in the wild potato plant leaves that make the beetle avoid them. Potato breeders at the Fredericton research and development centre used cross-breeding of a wild relative with com-mon popular potato varieties to develop a potato with built in beetle resistance. Not all of the potatoes from the cross carry the resistance, but the profile that Tai discov-ered identifies which ones do. Colorado potato beetles are already showing a resistance to the popular pes-ticides used by potato growers adding to the need for new solutions. Tai sees use of beetle resistant varieties together with in-tegrated pest management methods as an alternative approach to mitigate pesticide resistance. These resistant potato varieties can provide growers with PHOTO COURTESY OF ALEX MOLNAR. an option to avoid serious crop losses. Two of these new resistant potatoes are already in the breeding program and avail-able to industry to trial. Text courtesy of Agriculture and Agri-Food Canada. TOP CROP MANAGER/POTATOES IN CANADA | Spring 2018 7 PHOTO COURTESY OF AAFC.