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Production of Chlamydospores by Phytophthora palmivora in Culture Media. Janice Y. Kadooka, Former Graduate Research Assistant, Department of Plant Pathology, University of Hawaii, Beaumont Agricultural Research Center, Hilo 96720, Present address of senior author: Department of General Science, University of Hawaii, Honolulu 96822; W. H. Ko, Associate Professor, Department of Plant Pathology, University of Hawaii, Beaumont Agricultural Research Center, Hilo 96720. Phytopathology 63:559-562. Accepted for publication 1 November 1972. DOI: 10.1094/Phyto-63-559.

More than 70% of the chlamydospores produced by Phytophthora palmivora in a papaya juice medium had thick walls. However, only thin-walled chlamydospores were produced by the same fungus using the submerged culture method described by Tsao for P. parasitica. Thick-walled chlamydospores germinated poorly, whereas almost all thin-walled chlamydospores germinated in water, on V-8 juice agar, and on Noble water agar. After exposure to 46 C for 5 min, the proportion of thick- and thin-walled chlamydospores still capable of germinating on Bacto water agar was 85 and 15%, respectively. Thick-walled chlamydospores produced in papaya juice medium were morphologically and physiologically similar to those produced in naturally infected papaya fruits.