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Resistance

Protection of Watermelon and Muskmelon Against Colletotrichum lagenarium by Colletotrichum lagenarium. F. L. Caruso, Graduate Student, Department of Plant Pathology, University of Kentucky, Lexington, KY 40506; J. Kuć, Professor, Department of Plant Pathology, University of Kentucky, Lexington, KY 40506. Phytopathology 67:1285-1289. Accepted for publication 18 March 1977. Copyright © 1977 The American Phytopathological Society, 3340 Pilot Knob Road, St. Paul, MN 55121. All rights reserved.. DOI: 10.1094/Phyto-67-1285.

Inoculation of the cotyledons or first true leaf (leaf one) of four cultivars of watermelon and four cultivars of muskmelon with Colletotrichum lagenarium systemically protected the plants from disease caused by subsequent inoculation with this pathogen. Protection was noted as a reduction in the number and size of lesions. Plants remained protected 4 wk after the protecting inoculation; at this time plants possessed 10-14 leaves. Race 1, 2, and 3 of the fungus elicited protection. A single lesion on leaf one elicited significant protection and protection increased as the concentration of spores applied to leaf one were increased from 10³ to 10⁷ spores/ ml. The pattern of protection reported resembles that already observed in cucumber against this pathogen.