To demonstrate that the ERH applies to diffuse knapweed, it is essential to show that the absence of natural enemies has a significant positive effect on its success. One way to show this is to observe the effect of introducing some of diffuse knapweed's natural enemies into its novel environment. If diffuse knapweed, which generally thrives in its invaded environment, is significantly inhibited through the introduction of natural enemies, it can be concluded that diffuse knapweed is more competitive in the absence of its natural enemies. A recent effort at biocontrol of diffuse knapweed in Idaho's Camas County effectively reduced of knapweed to minimal levels through the release of the lesser knapweed flower weevil and the knapweed root weevil. Since both of the insects released are natural competitors of diffuse knapweed, and since this and other similar efforts at biocontrol have been successful, there is significant evidence that diffuse knapweed benefits from the absence of its natural enemies.