Impact of hail-netting on Vitis vinifera L. canopy microclimate, leaf gas exchange, fruit quality, and yield in a semi-arid environment

Abstract

Hail events have the potential to destroy grapevine shoots, reduce yield, and inflict economic loss upon growers. As a result, many grape growers have adopted the use of hail-netting to mitigate potential vine damage. Although hail-netting has been observed to prevent hail damage, Texas High Plains grape growers have expressed concerns regarding effects hail-netting may have on vine canopy microclimate, grapevine health, fruit maturity, fruit quality and yield. Therefore, over three growing seasons (2018 – 2020), field-grown vines (Vitis viniferaL. ‘Malbec’ and ‘Pinot gris’) were exposed to hail-netting, or grown without hail-netting. Each growing season canopy microclimate, leaf gas exchange, fruit maturity, yield parameters, and vegetative growth were monitored. Netting reduced canopy air and leaf temperature and decreased canopy vapour pressure deficit. By modifying light infiltration and leaf temperature, hail-netting altered leaf gas exchange. In addition, gas exchange differences were found between cultivars. Although fruit pH and total acidity were not different at harvest, fruit maturity measurements revealed total soluble solid development was influenced by netting and cultivar. Vine cluster numbers were greater for vines without netting and yield parameters were generally lower for ‘Malbec’ vines. Pruning weights indicate decreased vegetative growth for hail-netting and ‘Pinot gris’ vines. Results suggest grape-growers' use of hail-netting may allow growers to achieve fruit production goals. However, when using hail-netting, growers should consider possible management modifications due to changes in vine physiology, fruit maturation, and harvest schedules.