2014 Volume 56 Pages 85-87
Citrus melanose caused by Diaporthe citri reduces the commercial value of mandarin fruit. It is time-consuming for growers to control this disease in Wakayama Prefecture because it is necessary to treat the trees with fungicides four or five times. In this study, Ditianon 42% wettable powder was sprayed twice by late-June and Mancozeb 80% wettable powder was sprayed in August. According to a meta-analysis of ratio of severely diseased fruits in five experiments, the risk of this system is somewhat lower than that of the conventional system (fungicide Mancozeb was sprayed four times). This result suggests that it is possible that the frequency of spraying to control melanose can be decreased to three or four times.