Early defoliation (hand vs mechanical) for improved crop control and grape composition in Sangiovese (Vitis vinifera L.)

Early Defoliation (Hand vs Mechanical) for Improved Crop Control and GrapeComposition in Sangiovese (Vitis vinifera L.) By: C. Intrieri, I. Filippetti, M. Centinari, and S. Poni In: Australian Journal of Grape and Wine Research. 14(1):25-32. 2008 Early leaf removal caused a significant reduction in fruitset, yield per shoot, cluster weight,berries per cluster, and cluster compactness, and an increase in soluble solids, anthocyanins,and total phenols in this study. Leaf removal, either by hand or mechanical, can be an effectiveway to reduce yields and improve quality in heavily-cropping varieties, such as Sangiovese. - · With world-wide wine production exceeding consumption, crop control is currently apriority in many viticultural regions of the world. This is usually achieved through winter pruningin combination with cluster thinning. Whereas these practices work well in moderate-vigorsituations, they generally don’t work as well in vigorous vineyards, where imposed crop controlcan create excessive shoot growth and yield compensation due to a boost in the developmentof basal and secondary buds. - · As a result, and in the authors’ opinion, alternative ways of controlling crop should beexplored. The candidates with the most likelihood to succeed, they felt, included: growthregulators, mechanical flower or berry thinning, and early leaf removal. The goal of this studywas to determine whether pre- or post-bloom leaf removal, conducted by hand or mechanically,is able to limit yields in a high-cropping cultivar such as Sangiovese.