First identified in Manitoba in 2014, Verticillium longisporum has spread across the Prairies like wildfire. This soil-borne fungal pathogen causes verticillium stripe in canola, which is a stem striping disease that causes canola plants to ripen early, leading to lodging and eventual yield losses.
As soil temperatures warm in the spring, the microsclerotia in the soil seek growing canola roots, which then enter the plant and move in the xylem to the plant stem where the true damage happens. The impact of damage typically isn’t seen until harvest or shortly after, but hot, dry conditions help to express the plant damage earlier on. Canola stems will show half stem senescence, then become extremely fragile and shred to reveal the microsclerotia growing beneath the stem wall.
In 2024, 60% of fields surveyed through the Manitoba Provincial Canola Disease Survey were identified to have verticillium stripe present. Saskatchewan continues to find more fields every year with the disease, and Alberta is now having lab confirmed samples pop up across the province.
How to properly identify this disease from other common canola diseases, like blackleg and sclerotinia, has been the priority. Integrated management tactics like the basics of crop rotation, weed management, and scouting, don’t seem to be keeping verticillium stripe at bay. Many growers have reported significant yield losses from the disease and are in search of other management practices to try. Currently, there are no clear management recommendations for this disease.
With not much known about verticillium stripe, researchers are now focusing their efforts on trying to find solutions. Plant breeders have been finding ways to work with the disease within plant breeding programs to screen hybrids for tolerance towards verticillium stripe. The mechanism for resistance within hybrids is still not known and the industry struggles to find a resistant and susceptible check to use as an industry standard when screening for verticillium stripe tolerance. However, many plant breeders note susceptibility difference among hybrids infected by verticillium stripe, which can be used to help promote hybrids that should handle the stress from the disease better than others. This is one small step in the direction of managing verticillium stripe in canola and highlights the hope there already exists some background tolerance within Canadian canola germplasm.
Verticillium stripe is widespread and here to stay, so learn how to properly identify it in the field against other canola diseases. Industry collaboration will be key to better understand and develop management practices against this disease.
