Title: 20 years of field research on fungicide sensitivity of the plant pathogen Sclerotinia homoeocarpa

Presenter: Dr. Tom Hsiang

University:  School of Environmental Sciences, University of Guelph, Ontario, Canada

Time: 9:00-11:00, June 8, 2015

Venue: Room E201, Institute of Microbiology, Chinese Academy of Sciences

Abstract: Dollar spot disease of grass caused by the fungus Sclerotinia homoecarpa is the most common disease of intensively managed turf grass. In 1994, before the start of the use of demethylation-inhibiting fungicides (DMIs) against turf grass diseases in Canada, a baseline study (435 isolates, 8 populations) was conducted on the sensitivity of this fungus to DMIs, and it found that most isolates and most locations were highly sensitive. In 2003 (469 isolates, 9 populations), after 10 years of use and up to 40 total DMI applications, some populations had shifted to less sensitivity. In 2013, from over 1000 isolates from 13 locations, the populations which had received many DMI treatments (25-78) over 20 years were much less sensitive (EC50=0.046 µg/mL) than those of the baseline 1994 study (0.008 µg/mL) or the 2003 study (0.030 µg/mL). These results demonstrate that with greater DMI fungicide use, there is a decrease in sensitivity to these fungicides and at some point, this may pose a problem for DMI fungicide control of dollar spot disease in Ontario.

Dr. Tom Hsiang is a Professor in the School of Environmental Sciences at the University of Guelph, Ontario, Canada, specializing in plant diseases. Before arriving in Guelph, he worked on fungal diseases of flowers and trees in Washington State, U.S.A, where he obtained his Ph.D. (University of Washington) and conducted post-doctoral studies (Washington State University). He is originally from Vancouver, B.C., Canada, and obtained his B.Sc. and M.Sc. degrees in Forest Biology/Pathology at the University of British Columbia.  His current teaching and research involve fungal diseases of trees and grasses, particularly biology of fungal pathogens and disease management, as well as fungal comparative genomics and genome sequencing & assembly. Website: www.uoguelph.ca/~thsiang