Most producers that grow canola are well aware of blackleg and the damage the disease can inflict on a canola crop. However, when we think of scouting for blackleg, we often think of clipping canola plants later on in the season when the disease is evident in stems.
Believe it or not, blackleg is a disease that can be found prior to seeding; and Justine Cornelsen, agronomy specialist with the Canola Council of Canada, says now is the time to be crawling through any stubble and residue looking for signs of the disease.
“It is an early-season disease, and that’s where it’s kind of tough and misleading at times since we usually see the severe symptoms at the end of the season, or near harvest. But if you can protect and manage your canola crops early in the season, you are going to do a better job of managing blackleg,” Cornelsen explains.
The one thing that producers can do now when they are field prepping is to look at old canola residue, especially if they are on a tight crop rotation that brings canola in every other year.
“You will be able to pick up that old residue and look to see if there are any of the fruiting bodies on it, which are a sign of blackleg,” she explains in the Canola School video below. “They are kind of black pepper-like material on that old residue. That’s your first sign of blackleg.”
When it comes to early season management, the best thing you can do as a canola producer is to choose a variety that is blackleg resistant. Cornelsen explains the other thing you can do, if you are on a tighter rotation and struggle with blackleg infection, is to look at an early-season fungicide application. Still, it has to be done during a very early season window in order to get your full ROI.
“For blackleg to be producing spores, is super early in the season. When we hit about 15 to 16 degrees Celsius, and have had just a little bit of moisture, that old residue is going to start producing spores. So you want to coat that early-season canola that’s coming out — the cotyledon canola — to help protect it. So often times we are missing that window. The earlier the better for a fungicide application.”
Learn more about yield loss, the critical window, and more, in the full conversation between Justine Cornelson and RealAgriculture’s Kara Oosterhuis, below: