VIEW ARTICLE

Disease Control and Pest Management

Reduction of the Severity of Verticillium Wilt of Cotton By The Growth Retardant, Tributyl [(5-chloro-2-thienyl)methyl] phosphonium Chloride. D. C. Erwin, Department of Plant Pathology, University of California, Riverside, 92502; S. D. Tsai(2), and R. A. Khan(3). (2)(3)Department of Plant Pathology, University of California, Riverside, 92502. Phytopathology 66:106-110. Accepted for publication 22 July 1975. DOI: 10.1094/Phyto-66-106.

The growth retardant, tributyl[(5-chloro-2-thienyl)-methyl]phosphonium chloride (TTMP), reduced the growth of cotton by about one third when used in soil in pots (50 mg/2 kg). Foliar application at 40-80 µg/ml had little effect on growth of plants in the greenhouse or in the field. Wilt symptoms were delayed when TTMP was applied to growing plants by soil drench in the greenhouse and subsequently inoculated with Verticillium albo-atrum. There were fewer propagules of V. albo-atrum in petioles of treated plants than in petioles of control plants. Foliar application in the field with TTMP (40 and 80 µg/ml) in June also consistently reduced the number of V. albo-atrum propagules in petiole tissue when assayed as late as September. In addition, the number of bolls per meter of row and the yield of cotton seed and lint were significantly increased.