Grape white rot, predominantly caused by Coniella vitis , has developed resistance to certain fungicides, posing a significant challenge for effective disease management. This study evaluated the sensitivity of 86 C. vitis strains collected from Shandong, China, to three triazole fungicides. The EC 50 values for propiconazole, difenoconazole, and tebuconazole ranged from 0.001 to 1.961 μg/mL, 0.001–4.719 μg/mL, and 0.004–9.230 μg/mL, respectively. The mean values were 0.267, 0.540, and 0.904 μg/mL for propiconazole, difenoconazole, and tebuconazole. 3.5% of the tested strains exhibited reduced sensitivity to all three fungicides. Correlation analysis revealed significant positive correlation in sensitivity between difenoconazole and propiconazole ( r = 0.821, p = 0.004), difenoconazole and tebuconazole ( r = 0.740, p = 0.045), as well as between propiconazole and tebuconazole ( r = 0.767, p = 0.001). As a botanical pesticide, eugenol demonstrated significant inhibitory effects on mycelial growth of reduced‐sensitivity strains, with higher efficacy than triazole fungicides. In field trials, a 0.3% eugenol soluble concentrate demonstrated an efficacy range of 83.49% to 92.84%, underscoring its potential as a viable alternative for managing grape white rot. The study provides a theoretical foundation for optimizing fungicide strategies.
Li et al. (Sun,) studied this question.