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

Combining biocontrol agents with different mechanisms of action in a strategy to control Botrytis cinerea on grapevine

“…Varieties with tight bunches are considered to be more susceptible to B. cinerea, not only because of compression among the berries, which can create wounds easily colonised by the pathogen, but also because of the intrinsically higher susceptibility of the epicuticular wax at the point of berry contact (Marois et al, 1986). The advantages of increasing bunch openness, achieved with the use of gibberellic acid, is still controversial (Ferree et al, 2003;Mundy et al, 2014) and bunch tightness should probably be considered in the wider context, being only one of the factors concurring in susceptibility to the disease in some varieties (Vail et al, 1998).…”

Techniques to modify cluster architecture and their effect on the viticultural performance of the Sauvignon Blanc cultivar

“…The concentrations of gibberellic acid and ProCa, as well as spray timing at full bloom, were chosen based on studies conducted in the United States, Luxembourg, and New Zealand, which reported effects of these growth regulators on cluster architecture and Botrytis bunch rot control (Ferree et al, 2003;Molitor et al, 2011;Mundy et al, 2014).…”

“…Botrytis bunch rot or gray mold, caused by the fungi Botryotinia fuckeliana (de Bary) Whetzel and Botrytis cinerea Persoon ex Fries in conidial form, is one of the most important grape diseases in the highland regions of Southern Brazil (Bem et al, 2017). This disease is a problem in regions with cool and wet macroclimates, and, in general, fungal infection is most likely to occur when clusters are dense and little exposed to the sun (Hed et al, 2009;Mundy et al, 2014).…”

“…It is possible to modify cluster architecture in different ways. One of them is by using growth regulators, such as gibberellic acid and prohexadione calcium (Ferree et al, 2003;Molitor et al, 2011;Hanni et al, 2013;Mundy et al, 2014). Another option is berry thinning, which, in Italy, is being widely used either combined with chemical thinning or as an alternative to it (IASMA, 2003;Hanni et al, 2013).…”

Unraveling the transcriptional complexity of compactness in sistan grape cluster

“…Gibberellin hormone plays a direct role in size and compactness of the clusters. It has been validated positive effect of gibberellin in reducing and increasing cluster compactness and size of berries, respectively [5,45]. One of the main factors in compactness of Sistan's Yaghooti grape and small size of berries is down regulation of GA gene which has a direct effect on reducing activity of gibberellin hormone in the process of grape cluster development.…”