Southern Alberta farmers growing cereals, winter wheat in particular, are advised to watch for wheat streak mosaic virus in their crops.
The leaf curl mites that carry the virus can be blown on the wind and in some cases can survive over winter if it has a green bridge.
Mike Harding, plant pathologist with Alberta Agriculture, says the virus is already threatening cereals in Kansas, Oklahoma, Texas, Nebraska, South Dakota and Montana.
Last year about a dozen Alberta fields were confirmed to have the virus. Harding said fields south of Highway 12 should be particularly scrutinized. That is the area south of Red Deer.
Wheat streak mosaic is characterized by light green or yellow streaks on the leaves that run parallel to the leaf veins.
The virus can limit production, depending on severity, but there are no effective in-crop treatments. Drastically affected crops can be harvested for greenfeed or silage.
Wheat streak mosaic looks similar to stripe rust in its early stages, but the latter disease produces orange pustules.