The maximum seasonal rate was used for these fungicides, although two extra applications of Rally were used. Leaf removal is used to increase exposure of the clusters to air movement, which reduces moisture buildup and thus reduces rot. Results Sacramento Trial . The results are shown in Table 1 . Disease incidence and severity were evaluated on September 9, two weeks after commercial harvest.
Bunch rot incidence is the percent of sampled clusters with bunch rot.
Rot severity is the percent of rotten berries in an affected cluster. Their product, incidence x severity , best approximates the total amount of rot in a treatment, according to R. Duncan. As one might expect, total rot in the Rally and Abound treatments did not differ from untreated vines. Rot in the gibberellic acid, leaf pulling, and Elite treatments was significantly less than untreated vines, and did not differ from each other. However, sour rot was somewhat lower in the gibberellic acid treatment.