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Alberta forecasts high midge pressure in 2014

Dec. 16, 2013 - The Alberta wheat midge forecast for 2014 indicates a general decrease for midge risk in southern Alberta and a large increase for midge risk in the eastern Peace Region.

According to Alberta Agriculture and Rural Development's (AARD) Wheat Midge Forecast for 2014, individual fields throughout southern and central Alberta are showing moderate to high midge pressure, but generally midge pressure is low in those regions. Throughout central and southern Alberta, individual fields could have high populations even if the forecast in the area is low.

The 2013 fall survey included wheat growing areas throughout Alberta. The survey was expanded to all wheat growing areas of Alberta in 2011, including the Peace Region. Due to midge pressure in the Peace Region, the intensity of the sampling was increased in that area.

In total, 330 samples were taken from 59 counties. The survey involved taking soil samples from wheat fields after harvest using a standard soil probe. Larval cocoons were washed out of the soil using a specialized series of screens. Larvae were counted, and then dissected to determine if they were parasitized. The midge density displayed on the forecast map is based on viable (live, non-parasitized) midge larvae.

Scott Meers, insect management specialist with AARD, says the forecast is not intended to take the place of individual field monitoring. "The forecast for Alberta shows areas of risk for midge damage in 2014. It is important to note that over such a wide range, populations in individual fields can be, and often are, highly variable," he says. "Producers should plan to monitor their fields when the midge adults are flying and their wheat is in the susceptible stage. In all areas of the province, growers are urged to monitor their wheat fields from wheat head emergence to anthesis (the susceptible stage) for the presence of midge adults. Regular field scouting on multiple nights in succession is important in understanding the population in a particular field."

Although a number of factors influence the overwintering survival of the midge, the survey and map provide a general picture of existing densities and the potential for infestation in 2014.

"Weather conditions, specifically temperature and moisture will ultimately determine the extent and timing of midge emergence during the growing season," adds Meers. "Temperature and wind also play critical roles in egg laying activities of the adult female wheat midge. The level of damage from wheat midge is determined by the synchrony of wheat midge emergence and wheat coupled with the number of wheat midge."