Wheat • Oats • Barley Canola • Peas • Faba Beans TF (800) 444-8961 P (780) 352-3240 F (780) 352-6943 22252 TWP452 RR#1 New Norway, Alberta, T0B 3L0 [email protected] 32 www.seed.ab.ca | Advancing Seed in Alberta Sciences at the University of Alberta. “We've also found significant numbers of spores in wind-blown dust from infested fields which could contribute to local spread.” There is a continued spread eastward, he adds, with several new infestations recently found near the Saskatchewan border. “Part of why it often takes a few years for growers to ‘up their game’ when dealing with clubroot is because the impact on yield is often very slight,” notes Dan Orchard, agronomy specialist with the Canola Council of Canada. “It’s almost always found in a patch at the field entrance, and the overall field yield isn’t really affected. But if not managed, that patch will become much, much larger and potentially cause total loss of the entire crop.” At least 12 new strains of clubroot have been identified in Alberta since 2013, and they are all capable of overcoming the resistance in many clubroot-resistant canola varieties. “In 2016, these strains were confirmed in over 60 fields in Alberta, and in 2017, we identified another 42 fields with potential resistance issues,” Strelkov notes. “These new strains have likely emerged as a result of cropping of clubroot-resistant canola in short rotation in fields with moderate to severe clubroot infestations.” Orchard notes while best management strategies make a big difference, they are difficult to deploy. “This would include equipment sanitation, which growers have suggested could be hours and hours per piece of equipment for each field,” he says. “Not cleaning equipment is a risk growers seem to be accepting, although I believe many or most of them make sure equipment from unknown regions or potential clubroot regions is clean before entering their lands, which is a great practice to follow.” He adds there is evidence around the world and preliminary evidence in Alberta suggesting pH plays a major role in clubroot spread and severity. “Liming fields could reduce clubroot impact, but it’s another excellent management strategy that’s easier said than done,” Orchard says. “I’m convinced, however, that over the next few years and with the help of new technology, the industry will produce better lime recommendations, better pH mapping, better application techniques, and just a better understanding of lime and the benefits/challenges.” While he believes genetic resistance is currently the most significant factor in keeping this disease at bay, the fact that new clubroot strains are quickly appearing means growers need to deploy a multi-pronged approach. “The recipe for success would seem to be liming badly-infested patches and seeding them to a perennial grass until spore loads are manageable, coupled with planting resistant canola varieties and rotating sources of resistance on top of crop rotation.” Strelkov agrees that with the new strains appearing, it's unwise to use resistant canola varieties as a sole management strategy. He stresses longer rotations are important, and adds while “sanitation often is not viewed as practical, even steps such as trying to remove large chunks of soil from machinery or working infested fields last can be helpful.” Treena Hein www.canseedequip.com 1-800-644-8397 332 Packham Ave. Saskatoon, Sask. S7N 2T1 The Name in Grain Processing and Handling.