Not quite blackleg or sclerotinia? Could be verticillium
WINNIPEG, MAN. — Verticillium stripe, a stem disease, is showing up in more canola fields in Manitoba, Saskatchewan and Alberta, and harvest is a good time to look for it.
The fungal pathogen Verticillium longisporum causes stem cross-section discolouration that can look somewhat like blackleg and bleaching of the stem that can look somewhat like sclerotinia stem rot. But these diseases are all quite different in terms of yield risk and management, so it’s important to be able to tell them apart.
The good news, if you can say that about a plant disease, is that verticillium may not be a significant threat to Canadian canola production and the disease is not a regulated pest with any of our trade partners. But while we wait for new research projects to tell us more about possible yield implications, effective control measures and favourable environmental conditions, farmers and agronomists will want to learn to identify verticillium so it can be distinguished from blackleg and sclerotinia stem rot.
V. longisporum is a soil-borne fungus that infects roots and travels up the water-transporting xylem, plugging it late in the growing season. It can kill parts of or whole plants. Plants become extremely brittle and start shredding.