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Ecology and Epidemiology

Response of Rhizoctonia Blights of Tall Fescue to Selected Fungicides in the Greenhouse. S. Bruce Martin, Former graduate research assistant, Department of Plant Pathology, North Carolina State University, Raleigh 27695; C. Lee Campbell(2), and Leon T. Lucas(3). (2)(3)Assistant professor, and professor, respectively, Department of Plant Pathology, North Carolina State University, Raleigh 27695. Phytopathology 74:782-785. Accepted for publication 1 March 1984. Copyright 1984 The American Phytopathological Society. DOI: 10.1094/Phyto-74-782.

Benomyl, carboxin, PCNB, iprodione, chlorothalonil, and triadimefon were sprayed on tall fescue (Festuca arundinacea) plants in greenhouse experiments to determine their effect on foliar blight in plants inoculated with isolates of Rhizoctonia solani, binucleate Rhizoctonia-like fungi, and R. zeae after fungicide treatment. Benomyl treatments did not prevent increase of disease caused by binucleate Rhizoctonia-like fungi in one experiment, and on some benomyl-treated plants, disease was more severe than on unsprayed, inoculated plants. Isolates of R. zeae caused as much or more blight on benomyl-treated plants than on untreated plants inoculated with R. zeae. PCNB was ineffective against R. zeae and one of the R. solani isolates tested. Carboxin, triadimefon, iprodione, and chlorothalonil were effective in preventing infection by all Rhizoctonia spp. and Rhizoctonia-like fungi. Results indicated that all Rhizoctonia spp. induced disease on tall fescue and that the effectiveness of fungicide treatments in reducing disease varied among the Rhizoctonia spp.-fungicide combinations.