| Abstract: | Results are reported for four experimental trials carried out against Botrytis cinerea on wine grapes in Piedmont (Northern Italy) during 1979 and 1980, using fungicides with different mechanisms of action, alternately or in mixture. Good effectiveness was obtained not only with the exclusive use of dicarboximide fungicides but also with alternated spray programmes, for example using benomyl or captafol or dichlofluanid for the first two sprays and the dicarboximides only for the last two sprays. It was possible to reduce the number of sprays with the dicarboximides to only one (at beginning of ripening), by, for example, alternating dichlofluanid, vinclozolin and benomyl. Good results were also obtained using half-rate mixtures of fungicides with different mechanisms of action, for example benomyl or dichlofluanid mixed with one of the dicarboximides. In this way the selection pressure exercised by the dicarboximides is decreased. Moreover, the cost of treatments is reduced owing to the lower price of benomyl, dichlofluanid and captafol and because these fungicides are effective not only against B. cinerea but also against powdery mildew (benomyl) or downy mildew (dichlofluanid and captafol). |
