|Du toit, L|
Submitted to: Phytopathology Supplement; APSnet (Plant Pathology Online)
Publication Type: Abstract only
Publication Acceptance Date: 5/15/2005
Publication Date: 6/28/2005
Citation: Glawe, D.A., Dugan, F.M., Du Toit, L.J., Liu, Y., Rogers, J.D. 2005. Leveillula taurica in washington state: a case history. Meeting of the Western Soil Fungus Conference and the American Phytopathological Society - Pacific Division, schedule and abstracts, June 28-July 1, 2005, Portland, Oregon. Interpretive Summary: Leveillula taurica is a powdery mildew (a kind of fungus) that is parasitic on a wide range of plant species. It was not reported in Washington state until 2004, although it was previously well documented in other areas of North America and elsewhere. We have recently found L. taurica in Washington state on potato, onion and seaside arrowgrass. Most observations of this powdery mildew in Washington state have recorded only the asexual state, but both the asexual and sexual forms were seen on seaside arrow grass. On potato, L. taurica has been recorded as co-infecting with another powdery mildew, Golovinomyces orontii. This abstract re-capitulates observations of L. taurica in Washington state and supplies new information on their biological context as part of an American Phytopathological Society Pacific Division mini-symposium on powdery mildews in the western U.S.
Technical Abstract: Leveillula taurica was unknown in WA until 2004. First found in central WA on onion (Allium cepa), powdery mildew of this host was observed there in 1996 but the fungus was not characterized. Subsequent investigation of potato (Solanum tuberosum) plants in a field adjacent to powdery mildew-infected onion plants determined that L. taurica coinfected potato along with Golovinomyces orontii, a potato pathogen known in WA for more than 50 years. Also in 2004, L. taurica was found on greenhouse-grown seaside arrow grass (Triglochin maritima) in Pullman, WA. Both teleomorph and anamorph occurred on this host and the ITS sequence was identical to those reported for L. taurica on other hosts in Australia and Iran. It appears that L. taurica was introduced and is now endemic.