Growth and Reproduction of Dichotomophthora portulacae and Its Biological Activity on Purslane. J. M. Klisiewicz, Research Plant Pathologist, USDA, ARS, Department of Plant Pathology, University of California, Davis 95616. Plant Dis. 69:761-762. Accepted for publication 26 March 1985. This article is in the public domain and not copyrightable. It may be freely reprinted with customary crediting of the source. The American Phytopathological Society, 1985. DOI: 10.1094/PD-69-761.

Growth, reproduction, and biological activity of Dichotomophthora portulacae on purslane were studied in a controlled environment. Among several nutrient media that supported good growth of the fungus, potato-dextrose agar was selected for uniform growth, stability, and production of conidia by the fungus. Optimum temperatures were 30 C for growth and formation of sclerotia, 24 C for development of conidiophores and conidia, 33 C for germination of conidia, and 27 C for infection. Conidia germinated within 1 hr and infection occurred within 2 hr. Moisture was required on the plant for conidial germination and infection. Infection was also influenced by temperature, time, and inoculum density.