Growers and agronomists are searching for a solution to the problems caused by aster yellows in canola this year.
The disease caused yield losses across much of western Canada.
"The biggest impact is that it leads to less seed production, and a lot of the seeds are shriveled, small and blown away in the wind during harvest," explains Dr. Chrystel Olivier, research scientist with Agriculture and Agri-Food Canada.
The disease is caused by phytoplasma, or a bacteria-like pathogen, carried by the aster leafhopper.
"There not really anything you can do at the moment. There is no product to kill the phytoplasma directly, so that is not an option," explains Olivier. "You can spray for leafhopper, but if you want to spray, once you see the symptoms in the crop, it's too late."
She says the very noticeable symptoms of aster yellows will only show up in the crop three to six weeks after inoculation. The aster leafhopper blows in from the south, says Olivier.
"It is a migratory leafhopper that comes from the south U.S. when we have south winds. When they land on the crop, they start feeding and inoculating the crop. When they are infecting the plants, they induce symptoms that look like the plant is making leaves instead of flowers...therefore they're not making any seeds," she explains.
Olivier adds there are currently no canola varieties available that are resistant to aster yellows.