In the process of releasing plant pathogens for classical biological control of invasive weeds (Presentation) in the U.S., the Weed Biological Control program has the responsibility for collecting pathogens from weeds in their native habitats. Once the pathogens are collected, FDWSRU scientists must evaluate and characterize the pathogens, for effectiveness and safety, and, if the pathogens are acceptable, participate in their release into the U.S. Successes for FDWSRU include the rust fungi Puccinia chondrillina for control of rush skeletonweed (Emge, 1977, 1981); Puccinia carduorum for control of musk thistle (Baudoin, et al., 1993; Baudoin and Bruckart, 1996); and Puccinia jaceae for control of yellow starthistle (research article link). We are currently ready to petition for release of another two pathogens for control of tumbleweed and have another two pathogens in the wings for control of common crupina and milk thistle.

The program currently maintains about 1500 living pathogens on 98 weed species from 23 countries. In addition, there are data on another 3000 diseases on over 200 species of weeds that scientists of FDWSRU have collected from 47 countries.