Stripe rust could wipe out thousands of acres of winter wheat across southern Alberta and Saskatchewan if farmers fail to monitor their fields closely, said a plant pathologist.
Denis Gaudet, an Agriculture Canada research pathologist said the fast-moving disease has reached epidemic proportions in southern Alberta on winter wheat fields and could move to susceptible spring wheat varieties if farmers don’t watch it and take control measures.
“Most of the winter wheat is getting hit pretty hard now,” said Gaudet, of Lethbridge. He said the rust moves quickly in high moisture and cool conditions.
“It has pretty much hit all winter wheat fields in southern Alberta and will likely move to spring wheat varieties.”
There have also been reports of stripe rust in central Alberta and as far east as Yorkton, Sask.
In most years, stripe rust is only a concern to soft white wheat producers when the pathogen is carried on wind currents from regions like the U.S. Pacific Northwest in late summer. This year, heavy snowfall insulated the crops and allowed the stripe rust fungus to overwinter in southern Alberta. Cold weather normally kills it.
Stripe rust starts by covering lower leaves with orange spores that look like long stripes. The open pustules on the leaves can cause moisture loss and quickly turn into yield losses if the stripe rust reaches the flag leaf stage of the plant.
“Our goal is to protect the flag leaf. If it’s on lower leaves we recommend spraying. If it is in the flag leaf, it doesn’t make a lot of sense to throw good money after bad.”
The winter wheat variety Radiant is no longer resistant because the pathogen has mutated. The less common variety Bellatrix is not resistant. Most spring wheat varieties have resistance to stripe rust.
Gaudet said during a recent meeting of pathologists in North American, stripe rust was declared the most important new pathogen on wheat production.
With climate change and warming winters, it’s more likely stripe rust will overwinter in Canada and become a problem early in the spring.
“If it’s going to survive winters, I think it’s going to be an ongoing problem.”
