Field Evaluation of Pruning Wound Protectants for Efficacy and Persistence Against Botryosphaeria Dieback in Grapevine, Maule, Chile, 2024

Botryosphaeria dieback, caused by species in the Botryosphaeriaceae family, is a major grapevine trunk disease worldwide. Symptoms include vine decline, spurs and cordons dieback, and wedge-shaped wood necrosis. Infection occurs through pruning wounds, which remain susceptible for weeks. Therefore, wound protection is key to integrated management. This study evaluated efficacy and persistence of registered fungicides and a biological protectant against host-jumping Botryosphaeriaceae isolates. Field trials were conducted in 2024 on Vitis vinifera cultivar Cabernet Sauvignon in the Maule, Chile. Results showed that infection levels ranged from 6.7 to 26.7% for treatments applied 1 day after pruning and from 33.3 to 53.3% for treatments applied 15 days postpruning, highlighting the importance of timely application for optimal disease control. These findings provide evidence to guide grower decisions on pruning wound protection to reduce dieback risk.