福建省玉米小斑病菌对氟啶胺的敏感性及其与不同杀菌剂间的交互抗性

Sensitivity of southern corn leaf blight pathogen Cochliobolus heterostrophus to fluazinam and cross-resistance against diverse fungicides in Fujian Province

为明确福建省玉米小斑病菌Cochliobolus heterostrophus对氟啶胺的敏感性及其与不同杀菌剂间的交互抗性,采用菌丝生长速率法测定了该省5个地区的73株玉米小斑病菌菌株对氟啶胺的敏感性。结果表明,供试73株玉米小斑病菌菌株对氟啶胺具有较高的敏感性,所有菌株的有效抑制中浓度EC_(50)在0.0023～1.2863μg/mL之间,平均值为0.2573μg/mL,其敏感性频率呈连续单峰曲线分布,符合正态分布,因此可将EC_(50)平均值0.2573μg/mL作为福建省玉米小斑病菌对氟啶胺的敏感基线;5个地区的菌株群体对氟啶胺的敏感性差异不显著,但是不同地区的菌株个体间差异较大;氟啶胺与多菌灵、百菌清、丙环唑、烯唑醇、咪鲜胺和异菌脲之间均不存在交互抗性。

To determine the sensitivity of southern corn leaf blight pathogen Cochliobolus heterostrophus to fluazinam, and evaluate the cross-resistance between fluazinam and other fungicides, a total of 73 C. heterostrophus isolates collected from five regions in Fujian Province were used for testing their sensitivity to fluazinam using mycelial growth method. The tested isolates were highly sensitive to fluazinam, and the EC50 of these isolates to fluazinam were in the range of 0.0023-1.2863 μg/mL, with the mean value of 0.2573 μg/mL. The frequency curve of fluazinam was continuous and unimodal, and followed the normal distribution. Hence, the mean EC50 of 0.2573 μg/mL could be served as the baseline sensitivity of C. heterostrophus to fluazinam in Fujian Province. There was no significant difference in the sensitivity to fluazinam among C. heterostrophus populations from five regions; nevertheless, there was an obvious difference in the sensitivity to fluazinam among individual isolate from different regions in Fujian Province. There was no notable evidence of positive cross-resistance between fluazinam and carbendazol, chlorothalonil, propiconazole, diniconazole, prochloraz, and iprodione.