VIEW ARTICLE

Ecology and Epidemiology

Biology of Conidia, Ascospores, and Microsclerotia of Calonectria crotalariae in Soil. S. C. Hwang, Graduate Research Assistant, Department of Plant Pathology, University of Hawaii, Beaumont Agricultural Research Center, Hilo 96720; W. H. Ko, Associate Professor, Department of Plant Pathology, University of Hawaii, Beaumont Agricultural Research Center, Hilo 96720. Phytopathology 66:51-54. Accepted for publication 11 July 1975. DOI: 10.1094/Phyto-66-51.

Among the three types of Calonectria crotalariae propagules, microsclerotia were the most infective to papaya and ohia seedlings while the infection potential of conidia and ascospores was about the same. Ability of these three propagule types to colonize dead papaya stems did not differ significantly. The population of conidia, ascospores, and microsclerotia decreased 87, 46, and 20%, respectively, after an 8 month incubation in soil. Only microsclerotia remained viable after 8 months when colonized papaya tissues containing conidia, ascospores, and microsclerotia of C. crotalariae were incubated in soil. Microsclerotia, but not conidia or ascospores, were recovered from soils collected from planting holes in which papaya seedlings were killed by C. crotalariae 3 years previously in an abandoned field.