Midge, like tiny orange mosquitoes sucking the life blood from prairie cereal crops, are beginning their annual feast.
This year, the populations are up and conditions are right for a bug banquet, say entomologists.
Spreading across the Prairies and into the American great plains over the past decade, the orange wheat midge has found a home in the cereals of the flatlands.
The insect’s growth in numbers during the past four years is attributed to cool, damp summers, which support strong adult survival, combined with good snow cover nurturing cocooned pupa throughout the winter.
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Surveys performed last fall showed midge cocoon populations exceeding 1,200 per sq. metre in the Manitoba areas of Steinbach, Winnipeg, Portage la Prairie, Elkhorn, Killarney, Boissevain, Glenora and Brandon.
Midge in these areas often exceed the level where it makes economic sense to spray pesticides. The threshold for spraying is usually considered to be one midge for four or fewer cereal heads.
Dryness in the southwestern part of Manitoba may have reduced adults, say agrologists, but sampling has shown much of the Manitoba growing area is near the threshold.
Spraying in Manitoba and Saskatchewan has begun with later-seeded cereals just reaching the point where pesticide applications are recommended.
Saskatchewan areas exceeding the 1,200 cocoon per sq. metre level last fall included: Saskatoon, Simpson, Milden, Moose Jaw, Prince Albert, Vibank and along a line stretching from Grenfell to Yorkton.
“Populations of 600 cocoons can be a serious threat, so anyone with 1,200 should be watching their fields very carefully this season,” said David Hryhor, extension agrologist with Saskatchewan Agriculture.
“We haven’t had reports of midge problems yet, but I expect that at some point they will move into the province in the south or northeast. The later it gets, the better, and maybe we will be lucky in Alberta this year. So far so good though,” said Mike Dolinski, provincial entomologist for Alberta.
“Wheat midge populations can vary widely and adjacent fields can even be home to very different numbers, so each farmer must sample if they hope to know when or whether to spray,” said Debbie McLaren, of Manitoba Agriculture in Winnipeg.
