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Combatting The Evil Weevil

Reading Time: 2 minutes

Canola is like candy for a growing list of insects, of which the cabbage seed pod weevil is one of the latest.

“This insect is the most destructive pest of canola in Europe,” says Lloyd Dosdall, an entomologist and associate professor at the University of Alberta. He and his team focus on finding ways that farmers can control insect pests while reducing their insecticide use. His research team recently developed a new strain of canola designed to deter the cabbage seed pod weevil.

The insect was discovered in Alberta in 1995 and caused immediate concern among canola growers and researchers across Western Canada.

The cabbage seed pod weevil has spread rapidly in the southern part of Alberta. Heavy outbreaks were found in 1999 and 2000. The insect is capable of overwintering and could establish itself across all of the canola-growing provinces in Canada. The weevils lay eggs in canola pods and invade the crop at the bud stage. They also reduce pod formation on the plants and cause extensive damage to the crop.

Dosdall’s team examined ways farmers could produce crops that were less susceptible, and also examined the possibility of biological controls for the weevil. Early research had shown that white mustard was resistant to the insect. Since the plant is a close relative of canola, it could be crossed with the canola plant.

Dosdall partnered with geneticist Dr. Laima Kott at the University of Guelph. Kott successfully crossed the two plants and sent several genotypes to Dosdall in 2001. The plant was crossed using traditional plant-breeding techniques and is not genetically modified. Plants were seeded in test stations in Lethbridge.

One of the genotypes of the canola/mustard cross was found to deter seed pod weevils.

Dosdall’s research student, James Tansuy, conducted significant research on the new resistant lines. He found the weevils are less attracted to the odour or colour of the resistant lines, and are less inclined to lay eggs on these plants.

Dosdall said that the new canola is not an entirely perfect solution, as some seed pod weevils can complete their development on the crop. However, weevils produced on the new strain are smaller, lower in weight and less inclined to lay eggs on the crop.

“We’re confident that if farmers in weevil-infested areas grow this canola, their crop losses will be reduced,” Dosdall says. The need to spray will be reduced or eliminated in some cases.

The resistant variety should be available to producers in the next couple of years.

About the author


Alexis Kienlen

Alexis Kienlen lives in Edmonton and has been writing for Alberta Farmer since 2008. Originally from Saskatoon, Alexis is also the author of two collections of poetry, a biography, and a novel called "Mad Cow."



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