Effect of Protective Covers Against Biotic and Abiotic Disorders for Grape Production in Virginia

Grapes (Vitis spp.), globally cultivated for wine and other grape-based products, are susceptible to various diseases, pests, and disorders. These challenges are particularly pervasive in Virginia and viticultural regions in similar climates. Thus, growers routinely use insecticides and fungicides to protect their fruits. However, frequent or excessive use of these chemicals can pose environmental and human health risks and increase the chances of fungicide resistance. Many crop production systems use physical barriers to shield plant surfaces from biotic and abiotic environmental factors, particularly in Asian countries. This study evaluated the efficacy of paper bags, umbrella-style covers, and fruit-zone shelters in mitigating fungal diseases, insect infestations, and other factors that damage grape clusters. A series of field experiments were conducted at four commercial vineyards in Virginia and one research experiment station at Virginia Tech in five years with eight grape cultivars. Our results highlighted the importance of bag and fruit-zone shelter applications. Especially when these protection measures were applied around bloom, we observed reductions in the level of multiple diseases and insect- and bird-related damages. Fruit bagging resulted in significantly lower (P ≤ 0.05) mean severity and incidence of black rot, sour rot, sooty mold, and grape berry moth damage. Similarly, we found a significantly lower mean incidence of black rot, ripe rot, sour rot, and bird damage with the application of fruit-zone shelters. Thus, fruit bagging and fruit-zone shelter can be an effective cultural method for safeguarding grape clusters from different diseases, potentially reducing pesticide use and offering economic advantages to growers.