Blackleg is one of the key diseases faced by Prairie canola
producers and has largely been kept in check with the use of resistant
varieties and crop rotation. However,
over the past 10-20 years there have been concerns regarding observed shifts in
blackleg pathogen virulence in response to the major gene resistance used in a
number of varieties. Changes in
virulence patterns emphasize the critical need to stay on top of this disease;
producers and crop scouts can play a critical role by scouting fields to
monitor blackleg and detect any unexpected increases in disease levels on
resistant varieties. For blackleg a critical
time for scouting is later in the season to assess the prevalence, severity and
impact of this disease issue. When
assessing blackleg incidence and severity, it
is critical to correctly identify symptoms of blackleg and differentiate
these from normal or premature canola crop ripening due to a range of abiotic
and biotic factors. Recent Prairie
research has shown limited responses to in-crop fungicide when resistant
varieties are grown, and especially where this resistance is still highly
effective.
Protocols and scouting information can be found at the following links:
Protocols for blackleg surveying in canola