The out-of-sight, out-of-mind approach to wheat midge management needs to change to an out-in-the-field-monitoring approach, says Saskatchewan Agriculture.
According to the agency’s 2006 forecast, there will be a resurgence in midge populations in the eastern portion of the province, an outlook that caught some farmers off guard.
“I was rather surprised that (midge) was still in existence or that it potentially could be a problem,” said Rod Fedoruk, a seed grower from Kamsack, Sask. He had a bout with the pest on his farm in the 1980s and grain producers in nearby communities reported heavy infestations in their fields in the 1990s, but lately nobody has been talking about the insect. It has been all but forgotten.
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“I don’t hear the grumblings in the elevator about the midge damage anymore,” said Fedoruk.
But according to Saskatchewan Agriculture’s forecast, he should prepare for complaints in 2006.
“The eastern half of the province is showing a resurgence in wheat midge population,” said provincial pest specialist Scott Hartley.
Cocoons present in soil samples collected in a 2005 fall survey show populations are back at levels considered a significant risk to wheat producers.
John Gavloski, entomologist with Manitoba Agriculture, said annual surveys are not done in that province. Instead, he bases his forecast on producer experience from the previous growing season.
What he has gleaned from that analysis is that the Canadian Grain Commission downgraded some samples of wheat in the southwestern corner of Manitoba due to midge damage in 2005.
So after a number of years where the pest wasn’t on the radar screen, there are signs of mounting populations in Manitoba, although he wouldn’t classify it as a high-risk insect.
“I don’t think we’re at the point where I’d be telling people to change any seeding plans because of the wheat midge threat, but just to be careful and monitor,” said Gavloski.
Hartley said the threat is real in Saskatchewan, where the agency is advising producers in areas where population counts were greater than 1,200 midges per sq. metre to include the cost of insecticide application as part of their 2006 budgets.
Even in areas where the count is less than 600 midges per sq. metre there could be significant crop damage, so producers in hot spots should put monitoring back on their to-do lists.
“It was a nice reprieve but now they’re certainly showing some higher levels again,” said Hartley.
“Things like that you want to forget about. It has been a very devastating pest in the past.”
It is not unheard of for the insect to turn a 30-plus bushel spring wheat crop into a five bu. crop if left unchecked. It can also lead to serious downgrading in durum and other wheats.
Saskatchewan Agriculture has set economic thresholds for both types of damage based on monitoring that should be conducted during the susceptible stage, from heading to initial flowering.
Producers concerned about preserving yield should apply insecticide when there is at least one adult midge for every four or five wheat heads. At that level of infestation, yields will be reduced by approximately 15 percent if left unchecked.
In areas where growing conditions are favourable to the production of No. 1 wheat, chemical control may be required when populations reach one adult midge for every eight to 10 wheat heads to prevent any downgrading.
The cost of control is $6-$7.50 per acre. That is for the chemical; it does not include application costs.
“The chemical control options have given good control of the midge if timed properly,” said Hartley.
Wet conditions have led to the resurgence of wheat midge, which wasn’t much of a factor during the dry years in the early part of this decade.
While the 2006 outbreak isn’t anticipated to be as widespread as it was in the 1990s, there will be pockets in Saskatchewan where population levels are expected to be as high as they were back then, said Hartley.
But Gavloski noted that if there is a dry spring and early summer, the larva will remain dormant.
