VIEW ARTICLE

Disease Control and Pest Management

Integrated Control of Rhizoctonia Fruit Rot of Cucumber. J. A. Lewis, Soilborne Diseases laboratory, Plant Protection Institute, Agricultural Research, Science and Education Administration, U.S. Department of Agriculture, Beltsville, MD 20705; G. C. Papavizas, Soilborne Diseases laboratory, Plant Protection Institute, Agricultural Research, Science and Education Administration, U.S. Department of Agriculture, Beltsville, MD 20705. Phytopathology 70:85-89. Accepted for publication 24 July 1979. 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, 1980. DOI: 10.1094/Phyto-70-85.

Incidence and severity of cucumber fruit rot, which is incited by Rhizoctonia solani, were reduced in a Beltsville field in 1977 and 1978 after application of several components in an integrated pest management system. The major component, successful in both years, involved mechanical plowing of soils to a depth of 20–25 cm to remove inoculum from the surface layers of soil. In 1977, 85 and 52% of the fruit harvested from disked and plowed plots, respectively, had symptoms of disease. In 1978, comparable values were 75 and 37%. Application of photodegradable plastic mulch alone reduced incidence of disease by 75% in disked soils. Gypsum did not reduce disease. Corticium sp. and Trichoderma sp. (isolate WT-6) were as effective as captafol in disked plots. In plowed plots treated with isolate WT-6 or fungicide, only 11–12% of the fruits were diseased. Greater disease reduction was obtained by applying WT-6 in conjunction with plowing than when either component was used individually. Inoculum of R. solani, determined by beet seed colonization, was almost eliminated from the surface layers of plowed plots in both 1977 and 1978. Corticium sp. reduced the saprophytic activity of R. solani in soil. The mechanism by which WT-6 reduced fruit rot was not determined, although some mycoparasitic activity on R. solani was demonstrated.