Non-Peer ReviewedBlackleg, the most widespread disease on canola on the prairies, has been managed mainly through use
of resistant cultivars in combination with crop rotation. Over the past few years, crop rotation has been
tightened in favor of canola production due largely to profitability considerations but this practice can
speed up changes in pathogen race structure that may lead to losses of resistance for some of the current
canola cultivars. In this study, fungicides strategies were assessed as a second line of defense for control
of blackleg and canola yield benefit in case when the variety resistance is overcome by the pathogen. In
2011, the fungicide Headline, Quadris, and Quilt were applied at 2-4 leaf stage and/or bolting to target
varying periods of infection at three locations on the prairies. On the susceptible cultivar Westar, an
early application (2-4 leaf) of Headline or Quadris reduced the disease at Carman, MB, but not at
Melfort or Vegreville relative to non-treated controls. None of the fungicide treatments increased canola
yield substantially either. The study will be continued for two more years at multiple locations across the
prairies
