Cross pathogenicity studies with isolates of Fusarium oxysporum from either cucumber or watermelon pathogenic to both crop species*

SUMMARY Isolates of Fusarium oxysporum from Abaco, the Bahamas, whether obtained from wilted plants of cucumber (Cucumis sativus) or watermelon (Citrullus lanatus) , were pathogenic to cucumber, watermelon, and cantaloupe (Cucumis melo var. reticulatus). The West Indian gherkin (Cucumis anguria) , pumpkin (Cucurbita pepo) , and three cultivars of summer squash (C. pepo var. melopepo) were not susceptible. Strains of F. oxysporum from wilted cucumber or watermelon plants from Florida were highly pathogenic only to their original host species and are regarded as different formae speciales.