Wheat stem sawfly damage in Alberta is expected to be limited to small pockets of the southern part of the province this year.
Field surveys show low populations in most of the surveyed areas, including the traditional sawfly areas in the Special Areas and the County of Forty Mile.
The damage rates are based on surveys of 75 fields in 16 municipalities, said a report by the Alberta Inspect Pest Monitoring Network.
One field in the Municipal District of Acadia was found to have a “moderately elevated” infestation, while seven fields in the counties of Lethbridge and Forty Mile and the MD of Taber had elevated but still low numbers.
Female sawflies lay eggs inside wheat, rye, triticale and some varieties of barley. The larvae tunnel inside the stems until the crop starts to dry down.
They then migrate to the stem base as the crop begins to ripen and cut a notch most of the way through the stem. This can result in yield losses of 10 to 15 percent.
Spring wheat is the most susceptible to sawfly in Alberta, but winter wheat and durum can also become potential hosts.
The percent of stems cut by sawfly give an indication of the number of reproductive adult sawflies that will emerge in late June and early July. Winter conditions have little impact on sawfly populations.
Producers in areas with moderate to high levels of sawfly cutting should consider using solid stem wheat as part of their control strategy.