ARS | Publication request: BIOLOGICAL CONTROL OF YELLOW STARTHISTLE: NEW PROSPECTS FOR AN OLD PROBLEM.

Submitted to: Ecological Society of America Proceedings
Publication Type: Abstract Only
Publication Acceptance Date: July 14, 2004
Publication Date: August 1, 2004
Citation: Smith, L., Cristofaro, M., Pitcairn, M., Bruckart, W.L., Woods, D., Widmer, T.L., Berner, D.K., Drew, A.E. 2004. Biological control of yellow starthistle: new prospects for an old problem.. Ecological Society of America Proceedings.

Technical Abstract: Yellow starthistle (YST) is an invasive alien weed from the Mediterranean region that infests about 20 million acres in the western U.S. This noxious weed displaces native plants, elevates the risk of wildfire, and diminishes the value of rangeland for grazing and recreational use. A classical biological control program, initiated in the late 1960s, resulted in establishment of six species of seedhead-feeding insects. Several introduced insects are now widespread; however, they have not reduced plant densities at most locations to acceptable levels. A rust pathogen was approved for biological control of YST in California in 2003 and is now being distributed and evaluated. Foreign exploration has been expanded in Turkey and southern Russia to search for new agents that attack other parts of the plant. New prospects, several of which are new species, include a weevil that attacks the root crown (in the final stage of evaluation), flea beetle, leaf beetle, leaf-mining flea weevil, stem-boring weevil, blister mite, lace bug, rosette fly, tip-galling caterpillar, seedhead weevil, and several fungal pathogens. The diversity of prospective agents greatly increases our chances of finding some that are suitably host specific and sufficiently damaging to reduce yellow starthistle populations to innocuous levels in the U.S.