Rush skeletonweed is a non-native, invasive terrestrial forb listed as noxious, prohibited, or banned in nine western states. Rush skeletonweed originated from the Transcaspian region of Eurasia, its native range extending from Western Europe and northern Africa to central Asia. It has become widespread in wheat growing regions and rangelands of Idaho, Oregon, and Washington. It is considered an early seral species invading disturbed areas in crop, pasture, range and forest lands. It may also invade intact plant communities in low rainfall areas such as southwestern Idaho. Three biological control agents have been released to manage rush skeletonweed but they have been successful only in certain locations. The skeletonweed root moth, Bradyrrhoa gilveolella, was introduced in Idaho in 2002 but establishment has not been confirmed by 2009. The rush skeletonweed gall midge, Cystiphora schmidti, was first released in California in 1975 and is available for Prepared By: mass collection in California, Idaho, and Oregon. It damages rosettes and flowering stems reducing seed production. The rush skeletonweed rust fungus, Puccinia chondrillina, is the first exotic plant pathogen to succeed as a classical biological control agent in North America by reducing rush skeletonweed to “tolerable levels.” It is readily available for redistribution in California, Idaho, Oregon, and Washington. The effectiveness of biocontrol agents vary depending on local conditions and plant genotype. The rust appears more effective in California and the mite appears to be more important in eastern Washington. From: USDA NRCS