RT Journal Article
SR Electronic
T1 Timing and Intensity of Grapevine Defoliation: An Extensive Overview on Five Cultivars in Switzerland
JF American Journal of Enology and Viticulture
JO Am J Enol Vitic.
FD American Society for Enology and Viticulture
SP 427
OP 434
DO 10.5344/ajev.2019.19002
VO 70
IS 4
A1 Thibaut Verdenal
A1 Vivian Zufferey
A1 Agnès Dienes-Nagy
A1 Gilles Bourdin
A1 Katia Gindro
A1 Olivier Viret
A1 Jean-Laurent Spring
YR 2019
UL http://www.ajevonline.org/content/70/4/427.abstract
AB This article synthetizes observations from five experiments and reports on the effects of timing and intensity of defoliation on the white and red Vitis vinifera cultivars Pinot noir, Gamay, Merlot, Chasselas, and Doral. Intensive defoliation (removal of six basal leaves + six lateral shoots per shoot) was completed at three developmental stages of the grapevine: preflowering, flowering, and bunch closure. Preflowering defoliation had tremendous consequences on vine agronomic performance, mainly to the detriment of berry set; the yield was highly affected by preflowering defoliation (approximately -35% of that from vines with no defoliation). The intensity of defoliation allowed its impact on the yield to be modulated. The intensity of defoliation also had a positive impact against millerandage, sunburn symptoms, and Botrytis cinerea development. The berry skin thickness doubled and the polyphenol concentration increased significantly with preflowering defoliation. Due to preflowering defoliation, the red wines were often preferred for their color and mouthfeel. However, this practice had a negligible impact on white wine composition. Regardless, preflowering defoliation did not negatively impact wine parameters. In the context of this study, preflowering defoliation has potential to reduce vigor and control high production potential. Preflowering defoliation also represents a prophylactic solution to reduce both chemical applications and cluster-thinning costs.