Detection and Quantitative Estimations of Pythium aphanidermatum in Soil with Cucumber Seeds as a Baiting Substrate. Tsuneo Watanabe, Forestry and Forest Products Research Institute, P.O. Box 16, Tsukuba Norin Kenkyu Danchi, Ibaraki 305, Japan. Plant Dis. 68:697-698. Accepted for publication 17 February 1984. Copyright 1984 The American Phytopathological Society. DOI: 10.1094/PD-68-697.

Pythium aphanidermatum was detected in soils directly on 2% plain water agar plates, using cucumber seeds as a baiting substrate and Petri's salt solution for inducing sporulation. Sporangia, vesicles, zoospores, and zoospore discharge were observed on plates by 24–48 hr and sexual organs by 48–96 hr (at 30–35 C) after the trapping experiment was started. This method permitted detection and estimation of populations of P. aphanidermatum in naturally infested soils in Japan.