CAMROSE, Alta. – The canola disease blackleg has been found in the Peace region of northeastern British Columbia, said a B.C. ministry of agriculture plant pathologist.
Virulent blackleg was identified for the first time in at least 16 sites in both the north and south Peace regions of B.C., said Gayle Jesperson.
“We were quite surprised to find virulent blackleg when we didn’t see any last year,” said Jesperson. Blackleg was found around Rolla and a few other sites on the north side of the Peace River, she said, and more sites may be identified once the rest of the samples are analyzed.
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Almost 200 fields were randomly surveyed last fall. Because pathologists found positive samples on stubble, they plan to return in June to look for symptoms of blackleg on living plants.
Jesperson said it was only a matter of time before blackleg showed up in the canola-growing area. “We’re the last place in Canada to get it.”
Blackleg was first identified on the Alberta side of the Peace River region near Donnelly in 1992. Since then the disease, which can be spread by seed or air, has been found in several other Alberta Peace River region sites. The Peace region was considered to be the last blackleg-free area. About 120,000 acres of canola are grown in the B.C. Peace region.
Two types of blackleg can affect canola. Avirulent is a mild strain that causes superficial stem cankers late in the season, but does not affect crop yield. Virulent blackleg is more aggressive and causes stem cankers, girdling and lodging and can cause total crop loss in heavily infected fields.
Because of strong canola prices, many farmers have been shortening the recommended four-year rotation to two years between canola crops, Jesperson said.
While there is a fungicide registered for the control of blackleg, she said the most economical way to control the disease may be lengthening the rotational periods and cultivating crop stubble.
