VIEW ARTICLE

Disease Control and Pest Management

Pesticide - Plant Disease Interactions: Effect of Cycloate on Sugar Beet Damping-Off Induced by Rhizoctonia Solani. Jack Altman, Professor, Department of Botany and Plant Pathology, Colorado State University, Fort Collins, CO 80523; C. Lee Campbell, Graduate Assistant, Department of Botany and Plant Pathology, Colorado State University, Fort Collins, CO 80523, Present address: Department of Plant Pathology, 211 Buckhout Lab, The Pennsylvania State University, University Park, PA 16802. Phytopathology 67:1163-1165. Accepted for publication 11 March 1977. Copyright © 1977 The American Phytopathological Society, 3340 Pilot Knob Road, St. Paul, MN 55121. All rights reserved.. DOI: 10.1094/Phyto-67-1163.

Seedling survival of sugar beet cultivars MSH 212, FC 901, and FC 702/5 was significantly reduced (P = 0.05) in soil infested with Rhizoctonia solani and amended with cycloate (S-ethyl N-ethylthiocyclohexanecarbamate) at 4, 8, or 16 μg/g soil, compared to infested, nonamended controls. The survival patterns for cultivars FC 701/5 and Mono Hy A1 were similar to those for MSH 212, FC 901, and FC 702/5, although differences for FC 701/5 and Mono Hy A1 were not statistically significant (P = 0.05). Increased sugar beet seedling hypocotyl exudates in the presence of cycloate may be implicated in the increased damping-off with cycloate added at 4, 8, or 16 μg/g soil, whereas reduction in fungal growth rate and/or colonization ability caused by the herbicide at 32 μg/g soil balanced with increased exudates, is offered to explain why damping-off rates in infested soil were not increased by cycloate at 32μg/g soil.