Bacterial Leaf Spot of Cocoyam (Xanthosoma caracu), Incited by Xanthomonas campestris pv. dieffenbachiae, in Florida. Ken Pohronezny, Associate Professor (Pest Management), IFAS, University of Florida, Tropical Research and Education Center, Homestead 33031. Raymond B. Volin, Associate Plant Pathologist, and Wilbur Dankers, Biologist, IFAS, University of Florida, Tropical Research and Education Center, Homestead 33031. Plant Dis. 69:170-173. Accepted for publication 24 September 1984. Copyright 1985 The American Phytopathological Society. DOI: 10.1094/PD-69-170.

Bacteria isolated from leaf spots of cocoyam fit physiological and biochemical descriptions of Xanthomonas campestris. Cocoyam isolates were pathogenic to both cocoyam and Dieffenbachia maculata, and disease reactions were identical with those for X. campestris pv. dieffenbachiae. A 1983 survey of commercial fields in Dade County showed that bacterial leaf spot is widespread, affecting 74–100% of the observed plants.