棉铃疫病菌对甲霜灵的抗药性风险研究

Studies on resistance risk of the pathogen causing cotton boll blight to metalaxyl in Anhui

在实验室条件下,对分离自安徽省芜湖、无为、宣城、望江、肥东、寿县、滁州等7个地区的棉铃疫病菌(Phytophthora boehmeriae Sawada)对甲霜灵的抗药性进行了测定.结果显示,甲霜灵对各供试菌株的EC50分布为0.008 3～0.079 1 μg/ mL,平均为0.026 1 μg/ mL,远小于1 μg/ mL,且供试菌株在含甲霜灵质量浓度为1 μg/ mL的LBA平板上菌丝生长几乎完全被抑制,表明各供试菌株对甲霜灵十分敏感,但其敏感程度地区间存在较大差异.通过室内药剂直接诱变,获得抗甲霜灵菌株,经抗性测定结果表明,抗性菌株的抗性水平较其敏感亲本菌株高13 000倍以上,提示安徽省棉铃疫病菌对甲霜灵具有潜在的抗药性风险.

The metalaxyl-resistance of the pathogen of cotton boll blight,Phytophthora boehmeriae Sawada, isolated from cotton boll in Anhui Province was studied in vitro. The results showed that the mycelium growth of all isolates were almost inhibited on LBA medium with metalaxyl of 1μg/mL. All strains from 7 localities of Anhui Province were highly sensitive to metalaxyl with the EC50 values much less than 0.1μg/mL. The EC50 values of metalaxyl to all tested strains ranged from 0.0428-1.9373μg/ml with the average of 0.026 08μg/mL. It suggested that all strains from 7 parts of Anhui Province were very sensitive to metalaxyl,and that the sensitivity of all isolates to metalaxyl were very different among the localities. In this paper, the metalaxyl-resistant strains were easily obtained through mutagenisis of metalaxyl. And the resistant level of metalaxyl-resistant strains were also tested. The results indicated that the level is 13 000 times higher than that of their sensitive parents,suggesting that there might be resistance risk to metalaxyl in the isolates of the pathogen of cotton boll blight in Anhui.