Influence of Grapevine Canopy Management on Evaporative Potential in the Fruit Zone

¹ Department of Plant Pathology, University of California, Davis, 95616-5270.
² Department of Viticulture and Enology, University of California, Davis, 95616-5270.

Evaporative potentials (the capacity of the atmosphere to evaporate water as quantified with atmometers) of canopies of two grape varieties were evaluated in relation to method of vine training and removal of basal leaves around grape clusters. In canopies of Chenin blanc, evaporative potentials were significantly less in bilateral cordon-trained vines supported by a standard U trellis than in bilateral and quadrilateral cordon-trained vines supported by one-wire and Geneva double curtain trellises, respectively. In Sauvignon blanc, evaporative potentials were significantly less in bilateral cordon-trained vines supported by a 46-cm, T-crossarm trellis than in quadrilateral cordon-trained vines supported by Davis modified U and extended Wye double curtain trellises. Leaf removal increased evaporative potentials significantly in vine canopies of all training and support systems. Evaporative potential was correlated significantly with the density of canopies associated with imposed training methods and leaf removal treatment. As the number of leaf layers through a canopy decreased, evaporative potential increased.

Key words: Botrytis cinema, canopy management, evaporation, trellising

Submitted on October 12, 1988