Early leaf removal as a strategy to control Botrytis cinerea rot in Cabernet Sauvignon grapevine at high altitude regions

ABSTRACT Botrytis cinerea is one of the most important pathogens in the highlands of Santa Catarina State. This study aimed to evaluate the influence of different times of leaf removal on the progress of B. cinerea rot in Cabernet Sauvignon grapevine. Assays were conducted in the 2014/2015 and 2015/2016 growing seasons in a commercial vineyard located at 1230m (a.s.l.) in São Joaquim Municipality, Santa Catarina State (28º 17’ 39” S and 49º 55’ 56” W). The variety Cabernet Sauvignon was grafted on Paulsen 1103 rootstock, conducted in vertical shooting positioning, 3.0m x 1.5m spacing, and covered with hail protection net. Treatments consisted in leaf removal at the phenological stages: full bloom, buckshot berries, pea-sized berries, veraison, 15 days after veraison and plants not subjected to leaf removal. The disease was biweekly measured in bunches from the first symptoms to harvest. Disease progress curves were elaborated and compared according to: beginning of symptoms, time to maximum disease incidence and severity, maximum disease incidence and severity, and area under the disease incidence and severity progress curve. Results evidenced that early leaf removal should be recommended as management strategy to control B. cinerea in Cabernet Sauvignon grapevine grown in the highlands of Santa Catarina.

摘要 灰葡萄孢（Botrytis cinerea）是圣卡塔琳娜州高地最重要的病原菌之一。本研究旨在评估不同摘叶时期对赤霞珠（Cabernet Sauvignon）葡萄灰葡萄孢腐烂病程的影响。试验于2014/2015和2015/2016两个生长季，在圣卡塔琳娜州圣若阿金市（南纬28°17′39″，西经49°55′56″）海拔1230米的商业葡萄园开展。供试赤霞珠葡萄嫁接于Paulsen 1103砧木，采用垂直绑蔓栽培方式，株行距为3.0m×1.5m，并覆盖防雹网。试验处理设置为：于盛花期、霰弹粒浆果期、豌豆粒大小浆果期、转色期、转色后15天进行摘叶，以及不进行摘叶的对照组。自首次出现病害症状至采收期，每两周对果穗进行一次病害调查。绘制病害病程曲线，并基于以下指标进行比较：症状始发时间、达到最大病害发病率与严重度的时间、最大病害发病率与严重度，以及病害发病率和严重度病程曲线下面积。研究结果证实，早期摘叶可作为圣卡塔琳娜州高地赤霞珠葡萄灰葡萄孢病害防控的推荐管理策略。