b'pathogen is very diverse, so most fields will likely have multiple races. The idea is to choose a canola variety with resistance to the main avirulence genes in the field, if such a variety is available. Right now, we have four major genes identified (some varieties are identifying a fifth unknown gene) in Canadian canola varieties. Looking at our blackleg race profile in Western Canada, there would be the potential to adopt an Rlm7 resistance gene in our varieties, to match up with Avrlm7, which is becoming increasingly common here, says Cornelsen. She is hopeful additional major genes will become available in Canadian canola varieties in the coming years. A lot of the life sciences companies in Canada have access to materials with other resistance genes that are deployed in other countries. Also, researchers with Agriculture and Agri-Food Canada at Saskatoon have identified some new resistance genes, which will be available to the Canadian market. But it takes timewhen youre introducing a new trait or gene it can take upwards of 10 years to get the new varieties out. New Fungicide Options on the WayFungicides are not commonly used for controlling blackleg on the Prairies at present, mainly because producers dont necessarily see a return on investment within the application year. That is probably because we are missing the critical window of infection, explains Cornelsen. Just in the last year or so, we have really dialled in on when the critical stage for infection occurs for blackleg on the Prairies. Its the cotyledon to two-leaf stage. The plants infected at that very early stage will be the ones that suffer the greatest yield loss or may not even make it to harvest. If we can protect the plants at that early stage, we will really minimize the severity of the disease in some fields. Infection at this really early stage is not unusual. The infectedTo evaluate blackleg severity, clip the plant at the top of the root and assess the residue only needs a little moisture and temperatures around 15degree of infection visible in the cross section. to 16 C to start producing spores. [Often in a warm spring,] thePHOTO: JUSTINE CORNELSEN, CANOLA COUNCIL OF CANADApathogen is already releasing spores when the canola cotyledons are popping out of the ground, Cornelsen says. of Seedcare with Syngenta Canada. He explains Saltro will She explains the foliar fungicides registered for blackleg inprovide a new tool as part of an integrated disease management canola are labelled for the two- to six-leaf stage, by which timeapproach, together with crop rotation and genetic resistance, to the plants could already be infected. And even if the fungicidesmanage blackleg in canola, minimize yield loss associated with were registered for the cotyledon stage, a foliar application atthis disease and support the longevity of canola seed genetics. that timing would likely be impractical. Growers are oftenThis seed treatment contains a new active ingredient, busy with planting when canola is at the cotyledon stage. Andadepidyn, which is an SDHI mode of action. Syngenta its tough to wrap your head around the idea of spraying at theanticipates registration of Saltro seed treatment in time for use cotyledon stage because you would be spraying bare ground. in the 2021 growing season. Whats unique about Saltro is However, new seed treatments are on the way. Within theit will provide protection against airborne blackleg at canola next few years, we are going to have some new seed treatmentsemergence through what we now know to be a critical infection coming on the market that can protect the plant at that criticalperiod for the disease, the cotyledon stage, says Ewert.window from the cotyledon to two-leaf stage. I think the newWith blackleg management, we cant rely on just one tool, seed treatments will prolong the use of some of the genetics insays Cornelsen. I know we put our resistant cultivars up on a our blackleg-resistant varieties.pedestal, but weve got to look at prolonging their longevity and One of these new products is Syngentas Saltro. Were excitedusing all of our management tools. Crop rotation and scouting about what Saltro fungicide seed treatment will bring to theare really key pieces to managing this disease.management of airborne blackleg, says Scott Ewert, head Carolyn KingSpring 2020 25'