Over two million acres of once valuable grazing lands of the West have been invaded by common St. Johnswort (Hypericum perforatum L.), also known as Klamath weed and goatweed (Harris, 1951). The Ponderosa pine-bluebunch wheatgrass (Pinus ponderosa-Agropyron spicatum) association (Daubenmire, 1952) of Spokane County, Washington, is an area of heavy St. Johnswort infestation. As a means of controlling this serious pest, St. Johnswort beetles (Chrysolina gemellata and C. hyperici) were introduced into the Spokane area about 1950. It now appears that the beetles will be an effective means of control in the area under discussion. Conflicting reports on competitive ability of the plant have been presented. Sampson and Parker (1930) reported that St. Johnswort successfully competed with all types of herbaceous vegetation, including sod-forming grasses. On the other hand, Jenkins and Jackman (1938) have stated the plant will not thrive or spread in good stands of grass. Robbins, Crafts and Raynor (1952) have concluded that St. Johnswort is almost exclusively a grassland weed, occuring on pastures, meadows and ranges, and that the densest and most extensive infestation on western