Fusarium Wilt in Watermelon Cultivars Grown in a 4-Year Monoculture. D. L. Hopkins, Professor of Plant Pathology, University of Florida, Agricultural Research Center, Leesburg 32748. G. W. Elmstrom, Professor of Horticulture, University of Florida, Agricultural Research Center, Leesburg 32748. Plant Dis. 68:129-131. Accepted for publication 10 August 1983. Copyright 1984 The American Phytopathological Society. DOI: 10.1094/PD-68-129.

The year-to-year increase of Fusarium wilt in 10 watermelon cultivars grown in a 4-yr monoculture was inversely related to the resistance rankings of the cultivars. Crimson Sweet, rated as moderately resistant, was the exception. The mean rate of increase of Fusarium wilt was less in Crimson Sweet than in any other cultivar. In the fourth year, Crimson Sweet had the least wilt and the highest yield of all cultivars. Greenhouse bioassays for Fusarium oxysporum f. sp. niveum demonstrated a slower rate of increase of soil propagules with Crimson Sweet than with any other cultivar. Crimson Sweet appeared to have a unique type of resistance to Fusarium wilt that was somewhat more stable in a monoculture than that of other cultivars.