There has been ample opportunity so far this spring for the migration of harmful insects into the prairies.
Owen Olfert, research scientist with Agriculture Canada, tracks wind trajectory maps created by Environment Canada on a daily basis.
He has noticed a consistent number of forward trajectories of high altitude air masses moving north into Western Canada from Texas, California and Mexico.
“That is fairly unique. We’ve had two or three weeks now where we’ve had winds every week,” said Olfert.
Forward trajectories are tracked from 20 sites across the southern U.S. and Mexico. They predict where the high altitude winds from those sites are likely to travel over the next five days.
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Pests such as the diamondback moth, aster leafhoppers and aphids typically do not overwinter in Canada because it is too cold.
They head south to feed on broccoli, cabbage and cauliflower orchards in places like Texas, California and Mexico.
“The diamondback moth likes cabbage just as much as it likes canola,” said Olfert.
In the spring the insects can catch a ride on high altitude air masses and travel back to Canada to feed on cereal and oilseed crops.
In the spring of 2012 those winds transported hordes of aster yellow leafhoppers into the Prairie region leading to an outbreak of aster yellows disease.
According to Saskatchewan Agriculture, the outbreak affected 77 percent of the provinces’ canola fields with an average incidence of eight percent, leading to an estimated 2.4 to 5.6 percent yield loss in those fields.
Environment Canada also creates reverse trajectories from 50 sites across Canada that model where the winds came from over the past five days.
Olfert and his colleagues monitor the forward and reverse trajectories to get a sense of when farmers who provide information to the Prairie Pest Monitoring Network should be out with traps counting insect populations.
“It doesn’t say that these pests are going to arrive but it alerts people to be on the lookout,” he said.
Farmers are already out in their fields looking for diamondback moths.
“It’s usually essential for us to get a handle on those early populations if they show up, just for that reason.”
The network hopes to be providing its first weekly update for the growing season in early May.
