Sources ofRhizoctonia solaniandPythiumspp. in a Bedding Plant Greenhouse

Abstract

A greenhouse operation in Ohio [USA] was studied to determine the sources of damping-off pathogens and their mode of dissemination to bedding plants. Pythium spp. were isolated from steam-treated soil, but neither Pythium spp. nor R. solani were recovered from the other components of the potting soil mix. Both Pythium spp. and R. solani were isolated from dust and soil mix particle samples collected from walkways, floors and beds within the greenhouse and also from used seedling flats. When infested dust and soil mix particle samples were sprinkled on flats of seedlings, damping-off occurred. Sources of inoculum were present in this bedding plant greenhouse despite the use of soil steaming and routine sanitation procedure.