Synergistic effect of different adjuvants on azoxystrobin against three plant diseases

In this study, the synergistic effect of five adjuvants on azoxystrobin was investigated. The surface tension, the critical micelle concentration (cmc) and the maximum retention (R_m) were determined. The control efficacy of azoxystrobin and adjvants were compared by pot experiment. The results showed that the five adjuvants could efficiently reduce the surface tension, and increase R_m value on plant leaves. R_m value of Silwet408 was 7.32 mg/cm² on corn leaves. R_m value of Beidatong was 11.16 mg/cm² on wheat leaves. The five adjuvants could dramatically increase the control efficacy of azoxystrobin against wheat powdery mildew, soybean rust and corn rust. In terms of corn rust, the synergistic effect of Maidao (EC₅₀ value 0.016 mg/L) was the best one, followed by Beidatong (EC₅₀ value 0.029 mg/L). With regard to wheat powdery mildew, the synergistic effect of NF-100 (EC₅₀ 0.009 mg/L) and Silwet408 (EC₅₀ 0.009 mg/L) were both good. As for soybean rust, the synergistic effect of Maidao (EC₅₀ value 0.006 mg/L) and Silwet408 (EC₅₀ value 0.007 mg/L) were good. All in all, Silwet408 and Maidao have good synergistic effect with azoxystrobinto three plant diseases.