贵州省烟草黑胫病菌对甲霜灵的抗药性

Resistance of Phytophthora parasitica var.nicotianae to metalaxyl in Guizhou Province

为了明确贵州地区烟草黑胫病菌对甲霜灵的抗药性水平，从贵州省12个市、县采集黑胫病病株，经分离纯化鉴定，获得98株黑胫病菌株，采用生长速率法测定其对甲霜灵的敏感性。结果表明，采自不同地区的菌株对甲霜灵的敏感性差异较大，各供试菌株的 EC50值分布范围为0．4192～20．4861μg/mL；各地区平均 EC50在0．5519～10．9860μg/mL 之间；最低抗药性水平为1．00，最高抗药性水平为48．87，相差48．87倍，各地区平均抗药性水平在1．32～26．21之间。遵义、兴仁、贵定、赫章和兴义有抗甲霜灵菌株出现，除遵义部分菌株的抗性水平表现为高抗外，其余菌株对甲霜灵产生的抗性均处于中抗水平。

In order to investigate the resistance level of Phytophthora parasitica var.nicotianae to metalaxyl in Guizhou Province,samples of tobacco black shank were collected in major tobacco growing areas in 12 cities and counties of the province,and 98 P .parasitica strains were isolated.The sensitivity of these strains to metalaxyl was determined by mycelial growth rate.The results showed that the sensitivity of P .parasitica from different districts differed significantly,with EC50 values ranged from 0.419 2 to 20.486 1 μg/mL and the average EC50 val-ue between 0.551 9 and 10.986 0 μg/mL.The lowest and the highest resistance level were 1.00 and 48.87,re-spectively.The average resistance level of P .parasitica from different districts was between 1.32 and 26.21.The resistant isolates existed in Zunyi,Xingren,Guiding,Hezhang and Xingyi regions.The resistance levels of some strains in Zunyi were high,but the other strains were at the middle resistance level.