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CWB posts new midge maps

Weather data and computer modeling will help the Canadian Wheat Board post new daily maps estimating how and when wheat midge will emerge across the Prairies.

The CWB announced Wednesday that it will post midge emergence maps on its site every weekday until the end of July. The maps are “the only daily information source on wheat midge available
online,” the CWB said.

Midge emergence can be modeled using accumulated temperature calculations, or growing degree days (GDDs), the CWB said on its site. Data provided by Agriculture and Agri-Food Canada (AAFC) in Saskatoon suggest using a base temperature of 5°C for predicting midge emergence patterns using accumulated GDDs.

Thresholds for combined emergence of male and female midge are 693 (plus or minus 39) GDD for 10 per cent emergence; 784 (plus or minus 38) for 50 per cent emergence and 874 (plus or minus 41) for 90 per cent emergence, the board said.

Last year’s wheat midge outbreak was one of the worst ever, said CWB agronomist Mike Grenier in the board’s release. This year, “large areas” of the dark brown and black soil zones are at risk, based on fall soil sampling for cocoons. Areas at highest risk include north-central and eastern Saskatchewan, north-central Alberta between Edmonton and Calgary and western Manitoba, he said.

“Monitoring the emergence of wheat midge and developing populations will be key to success in managing this pest,” he said.

The daily maps created by the CWB are colour-coded with GDDs that indicate midge development stages, the board said. The maps use data from Prairie weather stations, including the CWB/WeatherBug network of on-farm stations, as well as AAFC’s pest modeling information.

“Going forward, the (online) tool will be refined and extended to other pests of concern to wheat and barley farmers,” the CWB said.

For now, Grenier said in the release, “farmers just need to bookmark the map page in their home computer or hand-held device and get a quick snapshot each day of how the midge is progressing in their area.

“This is a useful tool that will only
get better as our CWB/WeatherBug network expands to provide localized and
up-to-the-minute weather reports from more and more stations.”

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