EXPLORATION FOR PLANT PATHOGENS AGAINST TAENIATHERUM CAPUT-MEDUSAE (MEDUSAHEAD)

Authors: Widmer, Timothy; SFORZA, RENÉ - USDA-ARS-EBCL

Submitted to: XI Symposium on Biological Control of Weeds
Publication Type: Proceedings
Publication Acceptance Date: 12/1/2003
Publication Date: 4/1/2004
Citation: Widmer, T.L., Sforza, R. 2004. Exploration for plant pathogens against taeniatherum caput-medusae (medusahead). XI Symposium on Biological Control of Weeds (eds Cullen, J.M., Briese, D.T., Kriticos, D.J., Londsdale, W.M., Morin, L. and Scott, J.K.) pp. 193-197. CSIRO Entomology, Canberra, Australia.

Interpretive Summary: Medusahead ryegrass is an invasive weed in the U.S.A. with origins in the Mediterranean region extending to central Asia. It is a member of the grass family with seeds and currently it infests millions of hectares of land in the U.S.A., primarily in California, Colorado, Nevada, Oregon, and Utah. Medusahead ryegrass crowds out native plant species and is almost worthless as forage. Current management strategies have been ineffective. This study examines biological control, through the use of plant pathogens, as a possible management strategy. Surveys conducted in France, Spain, Turkey, Cyprus, and Greece resulted in the discovery of several damaging fungi attacking medusahead ryegrass. This will be beneficial by providing potential biological control candidates as an effective means to control this weed without using costly chemicals and labor.

Technical Abstract: Taeniatherum caput-medusae, medusahead ryegrass, is an invasive weed in the U.S.A. with origins in the Mediterranean region extending to central Asia. It is a member of the grass family with seed germinating in the fall and continuing to grow all winter. Currently, it infests millions of hectares of land in the U.S.A., primarily in California, Colorado, Nevada, Oregon, and Utah. Medusahead ryegrass crowds out native plant species and is almost worthless as forage. Current management strategies have been ineffective. This study examines biological control, through the use of plant pathogens, as a possible management strategy. In the literature, a few plant pathogens, including Ustilago spp., Tilletia bornmuelleri, Puccinia spp. and Fusarium culmorum, have been reported to occur naturally or through artificial inoculation on medusahead ryegrass. Surveys within the native habitat have resulted in finding several Ustilago spp., including U. phrygica, Tilletia bornmuelleri, two Puccinia spp., and Fusarium arthrosporioides. Preliminary studies have begun for identification of the species and host range and impact studies. A completed study involving F. arthrosporioides showed it was not host specific and, therefore, is not being pursued as a biocontrol agent. Further explorations will continue to search for new pathogens and testing for host specificity.