Development and Improvement of fungicidal spray program for apple production.

A basic spray program for apple in which fungicides are scheduled to spray at 15-day interval from petal fall to late August was formulated on the properties of several selected fungicides. In order to improve it, experimental plots, completely randomized block with 3 replications, were prepared in an orchard of 15 years old Fuji cultivar, and the spray programs in which only one chemical in the basic spray program was substituted with others were applied to each plot. It was revealed that only single substitution of the fungicide in the basic spray program makes a great differences in the control of white rot and bitter rot, and that the control property of the fungicides against the two diseases was quite variable even by the time of application. A simila! ! r trial was conducted in 2002 with a new basic spray program that was formulated with fungicides that have shown best control in each spraying time in the previous trial, similar results were obtained. Applying this method, the usefulness of certain fungicide in the spray program for apple could be properly assessed. Anthracnose of Robinia pseudo-acacia L. caused by Collectotrichum spp.