VIEW ARTICLE

Disease Control and Pest Management

Growth Retardants Mitigate Verticillium Wilt and Influence Yield of Cotton. D. C. Erwin, Department of Plant Pathology, University of California, Riverside, 92521; S. D. Tsai(2), and R. A. Khan(3). (2)(3)Department of Plant Pathology, University of California, Riverside, 92521. Phytopathology 69:283-287. Accepted for publication 25 September 1978. Copyright 1979 The American Phytopathological Society. DOI: 10.1094/Phyto-69-283.

The growth retardants tributyl[(5-chloro-2-thienyl)methyl]phosphonium chloride (TTMP), chlormequat (CCC), and N,N-dimethylpiperidinium chloride (DPC), when applied to the foliage in June or July, slightly mitigated symptom expression of Verticillium wilt of cotton caused by Verticillium dahliae and in most cases markedly reduced the internal population of V. dahliae propagules in the upper petioles of plants. These chemicals also increased the yield of cotton cultivar SJ-2 by 10–29% on land infested with V. dahliae and on noninfested land. The effective dosages of TTMP were 40–80 g/ha. Increasing the dosage to 160 g/ha had no effect on yield. CCC at 10 and 25 g/ha increased yield, but had no effect at 50 g/ha, and yield was decreased by 75 g/ha. However, yield was increased by DPC most effectively at 25 to 50 g/ha. Plant height was not affected by TTMP but was decreased by increasing dosages of DPC or CCC. The number of bolls set was slightly, but not significantly, greater on treated plants.