Effects of chemical and natural product treatments on bunch openness and botrytis bunch rot in Sauvignon blanc grapes

Abstract

Products containing different gibberellic acids (GA) and GA inhibitors were applied to grapevines during the 2009/10 and 2010/11 growing seasons to evaluate possible effects on bunch architecture and subsequent botrytis bunch rot (BBR) severity In the 2010/11 season the timing formulation and dose responses of the GA inhibitors in association with a biological control agent were also evaluated for their effects on BBR In both seasons the effects on yield and fruit quality and quantity were also measured to determine whether the treatments might affect commercial production There were no significant differences in either BBR incidence or severity in either season between any treatments including the standard fungicide programme Bunch openness was significantly modified by treatments but with no consistent pattern