Influence of Three Systemic Insecticides on Verticillium Wilt and Rhizoctonia Disease Complex of Potato. S. S. Leach, Research Plant Pathologist, ARS, USDA, University of Maine, Orono 04469. J. A. Frank, Research Plant Pathologist, ARS, USDA, and Associate Professor of Plant Pathology, The Pennsylvania State University, University Park 16802. Plant Dis. 66:1180-1182. Accepted for publication 1 April 1982. This article is in the public domain and not copyrightable. It may be freely reprinted with customary crediting of the source. The American Phytopathological Society, 1982. DOI: 10.1094/PD-66-1180.

The systemic insecticides/nematicides aldicarb and carbofuran and the systemic insecticide disulfoton, which are registered for use on potatoes, were evaluated for their effects on the development and severity of Verticillium wilt and the Rhizoctonia disease complex of potatoes. Granular formulations of these insecticides were applied preplant as an in-furrow treatment. Results obtained in 1976 and 1977 indicated that Verticillium wilt was not significantly affected by these chemicals. In both years, however, severity of the Rhizoctonia disease was significantly higher in plots treated with aldicarb than in the control plots. In 1978, aldicarb was applied in the seed furrow or the fertilizer band with either a gypsum or corncob diluent. The most significant increase in disease severity compared with the control was observed in the corncob diluent-fertilizer band aldicarb treatment. The most significant loss was a reduction in number of marketable tubers.

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