Effect of Early Fruit-Zone Leaf Removal on Canopy Development and Fruit Quality in Riesling and Sauvignon blanc

Lateral shoot development in the fruit zone (first four to five nodes on count shoots) of Vitis vinifera Riesling and Sauvignon blanc undergoing different fruit-zone leaf removal treatments. In 2012, lateral shoot growth was assessed and categorized on 15 Aug in (A) Riesling and (B) Sauvignon blanc. In 2013, lateral shoot growth was categorized on (C) 10 Sept in Riesling and (D) 29 Aug in Sauvignon blanc. Categories for shoot development included: (1) no laterals present; (2) laterals between 0 and 3 cm; (3) laterals greater than 3 cm but at or less than 15 cm; and (4) laterals greater than 15 cm. Letters denote significant differences between treatments within each year, using Tukey’s HSD at α = 0.05.

Spray coverage at bloom and preveraison between different fruit-zone leaf removal treatments in Vitis vinifera (A) Riesling and (B) Sauvignon blanc in 2013. Spray coverage near bloom in Riesling was assessed on 20 June; the preveraison spray coverage assessment was on 30 July. Spray coverage near bloom in Sauvignon blanc was assessed on 20 June; the preveraison spray coverage assessment was on 1 Aug. At the time of the bloom assessment, only the prebloom and bloom leaf removal treatments had been implemented. Water-sensitive cards were placed between basal and secondary clusters on count shoots just prior to spray application. Treatment means within an assessment date not connected by the same letter(s) denote significant differences using Tukey’s HSD at α = 0.05. Bars denote standard error of the mean.

Fruit set, expressed as percentage total flowers (estimated through calyptra counts) setting to berries for different fruit-zone leaf removal treatments in Vitis vinifera (A) Riesling and (B) Sauvignon blanc in 2012 and 2013. Bars denote standard error of the mean. No significant differences were seen among treatments in either variety or year.