The top insect threat to Canada’s wheat crop is expected to emerge this week, with delays in crop growth leaving it more vulnerable than usual to wheat midge, the Canadian Wheat Board said Monday.
The population of wheat midge, which lays eggs in developing wheat heads to feed on the kernels, is smaller this year due to last year’s cool growing season, pesticide use and the spread of a parasite, said Mike Grenier, agronomist with the CWB, which markets Western Canada’s wheat and barley.
But the wheat crop is as much as two weeks behind in development in parts of the Prairies, Grenier said. Much of the wheat crop is only now flowering – the stage where wheat becomes safe from midge.
“Farmers should really intensify their field scouting this week so they understand what’s going on,” Grenier said. One midge per four to five wheat heads is generally the threshold where the pest can lower yield, but one per eight to 10 heads can downgrade wheat quality.
Farms along the Saskatchewan-Manitoba border and in central Saskatchewan have the greatest risk of midge damage.
Drought in central Alberta and west-central Saskatchewan has helped keep midge in check – but grasshoppers like heat and dryness, Grenier said.