VIEW ARTICLE

Ecology and Epidemiology

Morphological, Physiological, Ecological, and Pathological Comparisons of Phytophthora Species Isolated from Theobroma cacao. M. K. Kellam, Postdoctoral researcher, Department of Plant Pathology, University of California, Riverside 92521; G. A. Zentmyer, professor, Department of Plant Pathology, University of California, Riverside 92521. Phytopathology 76:159-164. Accepted for publication 28 August 1985. Copyright 1986 The American Phytopathological Society. DOI: 10.1094/Phyto-76-159.

Phytophthora citrophthora was isolated from black pods and trunk cankers on cocoa trees. Isolates of P. citrophthora from cocoa were compared with P. palmivora and P. capsici from cocoa and P. citrophthora from citrus with respect to colony morphology, sporangium production, sporangial stalk lengths, compatibility types, and pathogenicity to cocoa and citrus. After 8 wk of growth in soil artificially infested with chlamydospores of P. palmivora and P. citrophthora or oospores of P. capsici, 100, 93, and 40% of cocoa seedlings were infected with P. palmivora, P. citrophthora, and P. capsici, respectively. Mortality at 8 wk was 67, 53, and 0% for seedlings infected with P. palmivora, P. citrophthora, and P. capsici, respectively. Single isolates of all three species produced homothallic oospores in inoculated cocoa pod tissue after a minimum of 5 wk.