The regional Extension publication, PNW492: Russian Thistle Management in a Wheat-Fallow Crop Rotation
was updated recently to reflect the latest research on the biology and management of Russian thistle in the inland Pacific Northwest. The first known introduction of Russian thistle to North America was near Scotland, South Dakota in 1873 or 1874. By 1910 it was widely distributed across the arid and semi-arid regions of the American west, an estimated 101 million acres. It is the most economically important summer-annual broadleaf weed found in the low-precipitation zone of the inland Pacific Northwest.
The discovery of glyphosate-resistant Russian thistle biotypes in Washington, Oregon, and Montana in 2015 has made management of this important weed more complicated, especially in reduced- and no-till cropping systems. If this is a weed that plagues your farming operation, consider reading this updated regional Extension publication soon.