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Autumn Wheat Midge Survey

21 September 2012
Alberta Agriculture, Food and Rural Development

CANADA - Midges are now found throughout central and southern Alberta and there are pockets of moderate to high midge risk through much of the area. Last growing season, producers throughout the central and southern Alberta were advised to monitor their fields carefully during this growing season for wheat midge.

This advice was based on the 2011 fall survey. Very low levels of midge were also found in 2011in the Peace region.

“The 2011 fall survey sampling included almost all municipalities in central and southern Alberta and the Peace,” says Scott Meers, provincial specialist with Alberta Agriculture and Rural Development.

“We will be starting the 2012 wheat midge survey in mid-September. This year’s survey will necessitate taking soil samples from farmers’ fields in every county where wheat is grown in the province. That means that surveyors will be entering fields to take samples. Farmers are asked to understand that surveyors will be gathering samples for this research which will be of benefit to them. In southern Alberta, surveyors will be surveying for wheat stem sawfly at the same time.”

This surveying is not intended to take the place of individual field monitoring but it does provide information for a general forecast of wheat midge risk for 2013.

“It is important to note that once midge has established in an area, it is unlikely to ever completely disappear,” says Meers. “Low lying and moist areas in a field provide a refuge, enabling the population to survive even when conditions are not favourable in the rest of the field. These low level populations, however, also help sustain a population of natural enemies.

“Parasitism of midge larvae by small wasps (Macroglens penetrans) has been important in keeping wheat midge populations below the economic threshold. These beneficial wasps tend to thrive in warm, dry conditions. Parasite populations will ultimately rise and fall with changes in the midge populations and are very important in managing population levels in Alberta. The forecast is adjusted for parasitism found while assessing the survey results.”

The wheat midge survey is conducted by Alberta Agriculture and Rural Development with assistance from Agriculture and Agri-Food Canada, Lakeland Applied Research Association, Battle River Research Group, Chinook Applied Research Association, Northern Peace Applied Research Association and Smoky Applied Research and Demonstration Association, County of Leduc, Parkland County, Two Hills County, Mountain View County, and the Municipal District of Wainwright. All samples will be processed by Alberta Agriculture and Rural Development.

For more information on wheat midge and for questions about the survey, contact the Ag-Info Centre at 310-FARM (3276). The 2012 wheat midge forecast can be viewed online.

Information on the 2012 survey and the 2013 forecast will be ready in early January 2013.

TheCropSite News Desk

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