河南省小麦赤霉病菌对戊唑醇的敏感性

Sensitivity of Fusarium graminearum Isolates from Henan Province to Tebuconazole

为明确河南省小麦赤霉病菌对戊唑醇的敏感性,采用菌丝生长速率法测定了戊唑醇对2016年自该省11个县(市)分离的113株病菌菌丝生长的毒力。结果表明,戊唑醇对小麦赤霉病菌菌丝生长最低抑制浓度为4μg·mL-1,对供试菌株的EC50值变化范围为0.010～0.237μg·mL-1,平均EC50为0.057±0.041μg·mL-1;敏感性频率分布图显示,病菌群体中虽然出现了对戊唑醇敏感性下降的亚群体,但仍有81.4%的菌株的敏感性频率呈正态分布,可将此部分菌株的平均EC50值(0.041±0.016μg·mL-1)作为小麦赤霉病菌对戊唑醇的敏感性基线;方差分析(LSD法)及SPSS聚类结果均显示,同一县(市)内的菌株对戊唑醇的敏感性差异较大,EC50最大值和最小值之比变化范围为1.10～14.23,而除周口沈丘及洛阳孟津菌株外,其余地区菌株对戊唑醇敏感性差异不明显,对戊唑醇的EC50平均值变化范围为0.038～0.101μg·mL-1,相差2.66倍;小麦赤霉病菌对戊唑醇与其对多菌灵、咯菌腈的敏感性之间无明显相关性。戊唑醇依然可以应用到河南省小麦赤霉病的化学防治上,但生产中应持续监测病菌对药剂的敏感性变化。

In order to detect the sensitivity to tebuconazole of Fusarium graminearum from Henan Province,113 isolates were collected from 11 counties in 2016,and their sensitivities to tebuconazole were determined by measuring the mycelial growth on the fungicide-amended media.The result showed that MIC(minimum inhibition concentration),which referred to the concentration that could inhibit the mycelial growth totally,was 4μg·mL-1.The EC 50(effective concentration that resulted in 50%of mycelial growth inhibition)values of all isolates ranged from 0.010 to 0.237μg·mL-1 and the average EC 50 value was 0.057±0.041μg·mL-1.The results of the sensitive frequency analysis revealed that low sensitive subcolony to tebuconazole had been observed in the tested isolates.The mean EC 50 value(0.041±0.016μg·mL-1)for 81.4%of all isolates showed a normal distribution,which was treated as the sensitive baseline of F.graminearum to tebuconazole.The results both variance analysis by LSD test and hierarchical cluster analysis by SPSS indicated that the isolates separated from the same region demonstrated different sensitivities,which implied that the ratio of maximum and minimum of EC 50 values of isolates from the same region ranged from 1.10 to 14.23.However,there was no significant difference on the sensitivity to tebuconazole among the isolates from most of the regions except those from Shenqiu and Mengjin County,which showed that the average EC 50 value of the isolates from all the regions ranged from 0.038 to 0.101μg·mL-1,and the ratio of maximum to minimum of average EC 50 values was 2.66.Especially,the correlation efficient existed between tebuconazole and carbendazim,fludioxonil was very low,which implied that there was no correlation of sensitivity of F.graminearum to the two fungicides.Though there had appeared low sensitive subcolony to tebuconazole in the field,tebuconazole could still be used to control wheat head scab in combination with carbendazim or fludioxonil to delay the development of resistance.At the same time,the sensitivity of F.graminearum to tebuconazole in Henan Province should be monitored continuously.