Botrytis cinerea inoculum dynamics in strawberry field

In vitro and in vivo studies were carried out on the dynamics of Botrytis cinerea inoculum on strawberries, with particular reference to the rate of spore production and dispersal. The rate of sporulation on strawberry leaves at several temperatures was determined in vitro, as well as the effect of rainfall, while the dynamic of spore dispersal was studied in vivo, by simulating different rain events. The optimum for sporulation was about 20°C, in agreement with what has been reported in bibliography, with significant spore production also on dry leaves. A non-linear model was fitted to the experimental data showing the relationship between temperature, time of incubation and rate of sporulation. Simulated rains caused detaching of the conidia from the leaf surface, without compromising the possibility of further sporulation on the same seat, which started in a few hours and progressed at an unchanged rate. In the in vivo trial, rainfall was the only meteorological parameter correlated in a significant way to the number of trapped conidia; it was responsible for spore dispersal from the sporulating surfaces on the floor to the strawberry flowers. An exponential model fitted the relationship between rain intensity and the number of trapped conidia accurately.