Russian knapweed grows in a variety of soil types and is not associated with any particular soil. Much of the initial invasion of this plant has been traced to contaminated alfalfa seed that was imported from Russia in the 1920's. More recent spread of Russian knapweed seed can be attributed to several different means including motorized vehicles, contaminated gravel for road surfacing, irrigation water, farm equipment, as well as humans, birds, and mammals. Russian knapweed forms dense stands and tends to exclude other plants due to its competitiveness and allelopathic properties. Due to these properties of Russian knapweed, infested areas eliminate native plant species as well as desirable agricultural plant species.
Russian knapweed is also on the state and local noxious weed list.
Curtail has shown to be effective for the control of Russian knapweed in the Tri River Area. Nozzles were on 20 inch spacings, containing Tee Jet 8002 spray tips. Applications were made at 4 mph with a pressure of 28 psi at the CO2 tank. The sprayer was calibrated and delivered 11.6 gpa of solution at the above speed, pressure, nozzle spacing, and spray tips. The handgun applications utilized a single nozzle equipped with a OC 8 spray tip with 28 psi pressure at the CO2 tank and the plant foliage was sprayed to wet.