Sensitivity of Fusarium graminearum to prothioconazole in Henan Province

The sensitivity of Fusarium graminearum to prothioconazole was determined with 278 strains collected from 11 cities in Henan Province from 2019 to 2021 using the method of mycelial growth rate in vitro. The results showed that the sensitivity frequency of 278 F. graminearum strains to prothioconazole was a unimodal curve and presented an approximately normal distribution. The EC₅₀ values of the strains ranged from 0.609 to 3.868 μg/mL, with the maximum value being 6.35 times the minimum value. The mean EC₅₀ was (1.741 ± 0.690) μg/mL. In addition, the sensitivity of F. graminearum to propiconazole in different years had no significant difference. For different years, the strains collected in 2020 were the least sensitive with an average EC₅₀ value of (1.894 ± 0.652) μg/mL, while the strains collected in 2021 were the most sensitive with an average EC₅₀ value of (1.643 ± 0.701) μg/mL. The sensitivity of F. graminearum to prothioconazole had significant differences in different regions. The strains in Jiyuan were the least sensitive with an average EC₅₀ value of (2.175 ± 0.632) μg/mL, while those in Kaifeng were the most sensitive with an average EC₅₀ value of (1.137 ± 0.419) μg/mL. The F. graminearum strains from Jiaozuo were the most varied in sensitivity (EC₅₀(Max.)/EC₅₀ (Min.) = 6.21) with an average EC₅₀ value of (2.073 ± 0.681) μg/mL, which was higher than the average of Henan Province. The strains from Xinxiang have the smallest differences in sensitivity (EC₅₀ (Max.)/EC₅₀ (Min.) = 1.75) with an average EC₅₀ value of (1.211 ± 0.349) μg/mL, which was lower than the average in Henan Province. This study provides a theoretical basis for the sensitivity of F. graminearum to prothioconazole in the future through three-year sensitivity monitoring.