By Nicole Philp, Canola Council of Canada
Discovery Seed Labs in Saskatoon is the first to offer a test of canola stubble to determine (1) if blackleg is present and (2) what race of blackleg it is. This can help farmers and agronomists make proper use of the new blackleg resistance-gene (R-gene) classification system when making seed decisions.
If a field has increasing incidence of blackleg, that is a sign that the pathogen population has shifted to a race or races that will overcome the dominant R-gene in the canola variety last grown on that field. By identifying the blackleg race, growers can then choose a variety with resistance to that race. For more on the R-gene classification system, I encourage you to watch the Canola Council of Canada’s new blackleg video. Go to youtube.com/canolacouncil and look for the title: “Blackleg in Canola: Understanding blackleg resistance and management tools”.
The ideal time to collect samples for blackleg testing is just before crop cutting when farmers and agronomists are doing their pre-harvest scouting. If stems seems to be infected, send in a 2-3” length of that infected stem. Include up to 12 stem samples. Discovery Seed Labs will test to confirm the presence of the blackleg pathogen, and it will test to identify the specific race. That is obviously too late to influence seed decision for this year, so another option is to collect old pieces of canola stubble this spring from fields planned for canola this year. Try to find pieces that seem to have blackleg pseudothecia on them.
Pseudothecia are small raised black spots. Discovery can test these old pieces for blackleg races.
Watch the blackleg video. Take a quiz. Get one CCA credit. After watching the new video noted earlier in this article, Certified Crop Advisors (CCAs) who get 10 out of 10 on a short quiz based on the video content will earn one credit in integrated pest management.
For links to Discovery Seed Labs and their blackleg test and for lots more on blackleg, go to canolawatch.org and search for the article “Blackleg: New stubble test from Discovery Seed Labs.”
-Nicole Philp is the Canola Council of Canada agronomy specialist for Southwest
Saskatchewan. Email her at firstname.lastname@example.org