VIEW ARTICLE

Effect of Motility of Phytophthora palmivora Zoospores on Disease Severity in Papaya Seedlings and Substrate Colonization in Soil. J. T. Kliejunas, Postdoctoral Fellow, Department of Plant Pathology, University of Hawaii, Beumont Agricultural Research Center, Hilo 96720; W. H. Ko, Associate Professor, Department of Plant Pathology, University of Hawaii, Beumont Agricultural Research Center, Hilo 96720. Phytopathology 64:426-428. Accepted for publication 31 October 1973. DOI: 10.1094/Phyto-64-426.

Zoospores of Phytophthora palmivora exhibited a tactic response to roots, but not to autoclaved stems, of papaya seedlings on natural soil. Motile zoospores were more effective in killing seedlings than nonmotile zoospores in soil, indicating that zoospore attraction towards plant roots is of importance in disease development. However, due to the difference in speed of germination, nonmotile zoospores were more effective in colonizing autoclaved papaya stems than motile zoospores.