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Disease Control and Pest Management

Pesticide — Plant Disease Interactions: Effect of Cycloate on Growth of Rhizoctonia solani. C. Lee Campbell, Graduate Assistant, Department of Botany and Plant Pathology, Colorado State University, Fort Collins, CO 80523, Present address of senior author: Department of Plant Pathology, The Pennsylvania State University, University Park 16802; Jack Altman, Professor, Department of Botany and Plant Pathology, Colorado State University, Fort Collins, CO 80523. Phytopathology 67:557-560. Accepted for publication 26 October 1976. Copyright © 1977 The American Phytopathological Society, 3340 Pilot Knob Road, St. Paul, MN 55121. All rights reserved.. DOI: 10.1094/Phyto-67-557.

Linear growth of Rhizoctonia solani after 72 hr at 20 C was significantly less on all nutrient concentrations of potato-dextrose agar amended with cycloate (S-ethyl N-ethylthio-cyclohexanecarbamate) from 10 to 100 μg/ml, than in controls without cycloate. Rate of growth of mycelium of R. solani was less in Czapek-Dox broth with 1 g yeast extract/liter amended with 4 or 8 μg/ml cycloate, than in controls. In raw soil amended with 4 and 8 μg/g cycloate, and in steamed soil amended with 4 μg/g cycloate, colonization of 5-mm-long mature bean hypocotyl segments by R. solani was slightly greater than in soil without cycloate. At 16 and 32 μg/g cycloate, colonization of hypocotyl segments was significantly less than in nonamended controls in both steamed and raw soil. Colonization of sterile sugar beet seeds by R. solani also was less with 8, 16, and 32 μg/g cycloate than in controls.