Control of Powdery Mildew in Vineyards Using Single-Application Vapor-Action Treatments of Triazole Fungicides. ROGER C. PEARSON, Professor,Department of Plant Pathology, Cornell University, New York State Agricultural Experiment Station, Geneva 14456. DUANE G. RIEGEL, Technician, and DAVID M. GADOURY, Senior Research Associate, Department of Plant Pathology, Cornell University, New York State Agricultural Experiment Station, Geneva 14456. Plant Dis. 78:164-168. Accepted for publication 2 November 1993. Copyright 1994 The American Phytopathological Society. DOI: 10.1094/PD-78-0164.

The triazole fungicides etaconazole, flusilazole, myclobutanil, penconazole, triadimefon, and triadimenol were applied as formulated products to cheesecloth wicks. The treated wicks, containing fungicide at the rate of 0.2-4.0 g a.i. per vine, were hung beneath the fruiting zone in the grapevine trellis during the period between bloom and 2 wk after shatter. Although no further fungicide treatments were applied for the growing season, fruit in treated vines in the most effective treatments remained free of powdery mildew until harvest. Control of powdery mildew was observed in a zone having a radius of approximately 45 cm from the treated cheesecloth. Control of powdery mildew equivalent or superior to that obtained with cheesecloth wicks was obtained when cotton rope or string was treated with penconazole and deployed as above. Less effective control was obtained when two cellulose sponges per vine were treated with penconazole and similarly deployed.

Keyword(s): sterol biosynthesis inhibiting fungicide,Uncinula necator