Page 1 Page 2 Page 3 Page 4 Page 5 Page 6 Page 7 Page 8 Page 9 Page 10 Page 11 Page 12 Page 13 Page 14 Page 15 Page 16 Page 17 Page 18 Page 19 Page 20 Page 21 Page 22 Page 23 Page 24 Page 25 Page 26 Page 27 Page 28 Page 29 Page 30 Page 31 Page 32 Page 33 Page 34 Page 35 Page 36 Page 37 Page 38 Page 39 Page 40 Page 41 Page 42 Page 43 Page 44 Page 45 Page 46 Page 47 Page 48 Page 49 Page 50 Page 51 Page 52 Page 53 Page 54 Page 55 Page 56 Page 57 Page 58 Page 59 Page 60 Page 61 Page 62 Page 63 Page 64 Page 65 Page 66 Page 67 Page 68FROM THE PRAIRIES to Western Canada, the prevalence of blackleg is gaining the attention of growers, agro- nomic advisers, retailers, seed compa- nies, governments and trading partners. The government of Manitoba reports that blackleg is becoming an increasing problem on the Prairies, with losses up to 50 per cent having been recorded in fields where susceptible varieties of canola were grown. During the past 10 years, growers in Western Canada have also witnessed this same trend, according to Curtis Rempel, who serves as the vice-president of crop production and innovation for the Canola Council of Canada (CCC). Severity is dependent on a number of factors, including geography, weather and cultivars grown. The disease, caused by the pathogen Leptosphaeria maculans, is also problematic in Australia and Europe. An estimated average yield loss of less than 10 per cent with maximum losses of 30 to 50 per cent have been documented as a result of blackleg development in oilseed rape crops, writes Sheau-Fang Hwang, lead author of the paper Blackleg (Leptosphaeria maculans) Severity and Yield Loss in Canola, in Alberta, Canada, recently published in the journal Plants. Hwang, an adjunct professor of plant pathology at the University of Alberta, goes on to says that in France, yield losses of five per cent to 20 per cent were reported in winter oilseed rape, while losses of eight to 29 per cent were documented in the United Kingdom from 1987 to 2005. These types of yield losses can have a significant impact on the farm Business-critical information for retailers selling seed and seed treatment products. BLACKLEG BUILDING IN CANADA economy, especially when more than 20 million acres of canola were planted across Canada in 2016. Beside the weather and geography contributing to the increase of black- leg, Rempel acknowledges that some blackleg resistance genes are no longer functional on the Prairies. “The concern is that in some areas, the Rlm3 resistance may be breaking down and the corresponding isolates have become more virulent,” says Dilantha Fernando, a University of Manitoba plant pathologist. Sakaria Liban, a pathologist with DL Seeds, explains that this has more to do with pathogen population. He cites a study done by researchers at the University of Manitoba showing that most of the lines in Canada are reliant on AvrLm3. “Isolates that can infect this line are being selected for,” Liban says. “What’s happened over the past 10 or 15 years is that the majority of the pathogen population has shifted to be able to infect the common resistance that the Canadian varieties carry.” As such, Rempel says new resist- ance labels are needed to help growers identify which resistance classes might be best for their fields. Blackleg Biology But once blackleg has established itself in a field, it’s hard to rid. The disease overwinters on infected canola stubble and can survive for at least two years. Experts say growers need to deploy a multi-pronged management approach. 18 More than 20 million acres of canola were planted across Canada in 2016.