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Ecology and Epidemiology

Factors Affecting Spore Liberation by Cladosporium carpophilum. T. R. Gottwald, Research plant pathologist, USDA-ARS, Southeastern Fruit and Tree Nut Research Laboratory, Byron, GA 31008; Phytopathology 73:1500-1505. Accepted for publication 19 May 1983. 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, 1983. DOI: 10.1094/Phyto-73-1500.

Conidial discharge by the peach scab fungus, Cladosporium carpophilum, from heavily diseased peach fruits was studied under controlled relative humidity (RH), temperature, wind speed, and red-infrared radiation (IR). As RH decreased from near saturation to 40%, spore release was minimal, but further decreases stimulated considerable spore discharge. Sustained periods of constant RH <40% also favored spore release which was enhanced by exposure to IR (>40 μE·m^-2·sec^-1). Spore release was stimulated by short IR exposures (~2 min) and brief (2-min) RH changes. Spore release at low RH was increased slightly by vibration, created by dropping a 50-g weight 5 cm onto the specimen chamber, especially when specimens were exposed to IR.