VIEW ARTICLE

Ecology and Epidemiology

Influence of Temperature and Wetness Duration on Infection of Strawberry Flowers by Botrytis cinerea and Disease Incidence of Fruit Originating from Infected Flowers. M. A. Bulger, Former graduate research associate, Department of Plant Pathology, The Ohio State University, Ohio Agricultural Research and Development Center, Wooster 44691; M. A. Ellis, and L. V. Madden. Associate professors, Department of Plant Pathology, The Ohio State University, Ohio Agricultural Research and Development Center, Wooster 44691. Phytopathology 77:1225-1230. Accepted for publication 27 February 1987. Copyright 1987 The American Phytopathological Society. DOI: 10.1094/Phyto-77-1225.

Strawberry flowers were inoculated with a conidial suspension of Botrytis cinerea at temperatures between 5 and 30 C and wetness durations up to 32 hr. There was an increased incidence of flower infection with increased wetness duration for all temperatures tested. Optimum temperature for flower infection was ~ 20 C, with 100% infection at 24 hr wetness. As with flowers, there was a general increase in the incidence of fruit infection resulting from flower inoculations with increased wetness duration at all temperatures. For inoculation of flowers at 20 C, the highest incidence of fruit infection (~ 60%) was recorded for 32 hr of wetness. Flower and fruit infection was greatly reduced above 25 and below 15 C for all wetness durations. Regression models were fitted to the data. A logistic model was chosen to describe the incidence of petal and stamen necrosis and incidence of fruit infections originating from infected flowers as functions of temperature and wetness duration. Coefficients of determination for the data combined from both runs of the experiment were 0.90, 0.87, and 0.92, respectively. A logarithmic model was used to describe the relationship between the incidence of petal necrosis and incidence of infected fruit from infected flowers. All models had significant coefficients and, based on an F test, the experimental runs were not significantly different.