VIEW ARTICLE

Ecology and Epidemiology

Effects of Temperature and Duration of Surface Wetness on Spore Production and Infection of Cucumbers by Didymella bryoniae. Carol J. Arny, Former research assistant, Department of Plant Pathology, The Ohio State University, Ohio Agricultural Research and Development Center, Wooster 44691; Randall C. Rowe, professor, Department of Plant Pathology, The Ohio State University, Ohio Agricultural Research and Development Center, Wooster 44691. Phytopathology 81:206-209. Accepted for publication 28 September 1990. Copyright 1991 The American Phytopathological Society. DOI: 10.1094/Phyto-81-206.

Effects of temperature on spore germination, sporulation, infection, and symptom development on stem pieces and flowers of cucumber infected with Didymella bryoniae were studied under conditions of 100% relative humidity (RH). Infection of leaves and petioles of young, intact cucumber plants was studied at various combinations of temperatures and durations of surface wetness. Processes studied at 100% RH occurred over a wide range of temperatures (20–28 C), with an optimum of 24–25 C. When temperature and duration of surface wetness were varied in combination, wetness duration was the most important factor that affected the proportion of leaves and petioles that became infected.