Effect of early defoliation and calcium prohexadione application on the incidence of cluster rot and grape composition
Abstract
Bunch rot is one of the main causes of grape quality losses, especially in rainy summers. In a Tannat vineyard, cultivation techniques were evaluated for two years in order to reduce cluster compactness and decrease rot incidence: early leaf removal (DPF) up to node 6 and calcium prohexadione (PHCa) at a single dose of 1500 ml*ha-1, at stages 17 and 23 of the Modified Eichhorn & Lorentz System (E-L System). Both treatments were compared to a commercial control (TC). All treatments received the same chemical management. The results of the study were conditioned by a marked yearly effect with; the 2017 season having highly favorable conditions for disease development. DPF treatment modified canopy microclimate, resulted in less compact clusters and reduced rot incidence, with a 30% yield reduction when compared to the control. PHCa treatment caused a reduction in berry size, without affecting yield, while disease incidence did not have a significant difference when compared to the control. Both treatments modified berry composition, in particular, increasing phenolic richness. DPF treatment resulted on a higher proportion of exposed clusters, whereas the PHCa modified berry components and flavonoid synthesis. Both techniques are promising to improve cluster sanitary status and must composition.
Issue: GiESCO 2017
Type: Extended abstract
Format: Poster
Authors
1 Facultad de Agronomía, Universidad de la República, Departamento de Producción Vegetal
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Keywords
early leaf removal, calcicum pro-hexadione, bunch rot, grape composition