In Vitro Effects of Metalaxyl on Growth, Sporulation, and Germination of Phytophthora parasitica and P. citrophthora. A. Farih, Department of Plant Pathology, University of California, Riverside 92521. P. H. Tsao, and J. A. Menge, Department of Plant Pathology, University of California, Riverside 92521. Plant Dis. 65:651-654. Accepted for publication 18 November 1980. Copyright 1981 American Phytopathological Society. DOI: 10.1094/PD-65-651.

Metalaxyl at low concentrations was highly inhibitory to mycelial growth and formation of sporangia, chlamydospores, and oospores of Phytophthora parasitica and/or P. citrophthora. Chlamydospore germination was sensitive to low concentrations of metalaxyl, but zoospore germination was not greatly reduced. With both spore types, however, germ tube growth was highly sensitive to metalaxyl. Metalaxyl therefore controls the diseases caused by these Phytophthora fungi by affecting the pathogens at all stages of their life cycle.

Keyword(s): spore germination.