Shove over blackleg and sclerotinia — there’s a new kid on the block.
Fusarium wilt is a plant disease discovered just last year drying up canola plants in Alberta fields.
Ralph Lange, a scientist with the Alberta Research Council, has been tracking and researching the fungus ever since.
He suspects the disease may have existed for years, but was mistaken for other types of infections like blackleg and sclerotinia.
“It can be found in small amounts in many fields,” Lange said. “For the most part it isn’t a problem. When it gets to be a problem, it is very serious. It can affect as much as 30 percent of the crop.”
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Last year, the new fusarium was found in the Peace River district and in one field near Fort Vermilion. This year, it has appeared in the Peace district and in a belt running from Sedgewick through Vegreville and northeast to Bonnyville and St. Paul.
The fungus is concerning Alberta agronomists because there is no way to control it.
Lorraine Harrison, a provincial plant pathologist from Grande Prairie, said the fungus seems to be in the soil, but can be seed borne. Some canola varieties are more susceptible than others.
“It was found in some breeder plots in Manitoba last year, as well as in Alberta,” she said.
“Individual rows would be affected by the fusarium and others right beside them were untouched.”
Lange said despite rumors in the farm community about certain varieties of canola being overly susceptible to the disease, there are many factors to consider.
“Yes, we have seen it affect Quest,” he said.
“It has also affected a lot of other varieties as well. Quest is very popular and that is why (the fungal infection) is more apparent to producers. Not that (Quest) is the only one under attack.”
He said the disease is present in both Argentine and Polish varieties.
Some canola varieties appear to be resistant to the fusarium, which means plant pathologists should be able to isolate the resistant genes that plant breeders can introduce to their breeder lines.
“I expect that this is one disease that resistance can be bred into the plants very quickly,” said Lange.
Although fusarium wilt can be confused with other diseases, it can also be identified by its own characteristic symptoms.
Plants have stunted, tiny pods that have failed to fill. There are no visible lesions on visible roots. Scraping the bark away will reveal reddish lines of fungus running parallel to plant growth.
Unlike sunscald, these marks are in the core of the stem. The plants may be infected on just one side and turn a bright golden, straw-like color with a pink tinge at the base. They prematurely desiccate and turn a grey to brown color.
Most obvious is the diseased plant’s tendency to remain standing after death.
In minor infections, the plants will tend to shatter easily, a condition noticeable at swathing.
Two soil-borne fungi have been identified as the sources for the disease, fusarium oxysporum and fusarium avenaceum.
Producers who suspect they have the fungus in their crops should contact their local provincial agronomist and take a sample of the effected plants for later testing.
For more information visit www.agric.gov.
ab.ca/pests/diseases/fusarium-wilt_canola.html.
