Influence of Temperature, Wetness Duration, and Wetness Interruption on Grapevine Berry Infection by Coniella vitis

The grape white rot, caused by Coniella vitis, is a major threat in Chinese vineyards. Still, the environmental determinants governing the infection process are poorly understood, hindering the development of risk-based control strategies. This study investigated how temperature, wetness duration, and wetness interruption jointly influence infection in two grapevine cultivars (Chardonnay and Riesling) at berry development and maturation stages. Disease severity was significantly higher in mature berries than in developing berries, with Chardonnay being consistently more susceptible than Riesling. Optimal conditions for infection were 25°C, with 18-24 h of wetness, under which disease severity exceeded 90% at berry maturity. A temperature-wetness response equation accurately described infection dynamics at both berry growth stages (R² ≥ 0.893) and was used to construct infection risk classification charts. There was a high infection risk in mature berries when the temperature ranged from 16°C to 34°C. The critical wetness duration required for infection was 2 hours. The temperature range for high infection risk in developing berries was narrow (14-28°C) and the wetness threshold long (≥12 h). Wetness interruption significantly suppressed infection, particularly during berry maturation, when extended dryness of 2-12 h reduced disease severity by up to 31.7%. A wetness-interruption equation was developed (R² ≥ 0.927) to effectively quantify the inhibitory effect of dryness duration on berry infection. This study elucidates the interactive roles of temperature, moisture continuity, and dryness intervals in driving C. vitis infection, and provides mathematical equations to support the development of mechanistic models for a precision management of grape white rot.