VIEW ARTICLE

Infection and Colonization Potential of Sporangia, Zoospores, and Chlamydospores of Phytophthora palmivora in Soil. W. H. Ko, Associate Professor, Department of Plant Pathology, University of Hawaii, Beaumont Agricultural Research Center, Hilo 96720; Mary J. Chan, Technician, Department of Plant Pathology, University of Hawaii, Beaumont Agricultural Research Center, Hilo 96720. Phytopathology 64:1307-1309. Accepted for publication 9 May 1974. DOI: 10.1094/Phyto-64-1307.

Among the three spore types of Phytophthora palmivora tested, sporangia were the most infective to papaya seedlings, chlamydospore infection potential was intermediate, while zoospores were the least infective. Infection potential of a sporangium was higher than that of the 16 zoospores released from it. Of the three spore types, sporangia also were the most effective in colonizing autoclaved papaya stems. However, the colonization potential of zoospores and chlamydospores was about the same. When zoospore concn was increased to 16 times of sporangium concn, percentage of papaya stems colonized by sporangia was about the same as nonmotile zoospores, but was higher than motile zoospores.