多主棒孢菌对乙霉威和腐霉利敏感基线的建立及抗药性监测

Establishment of Sensitive Baselines and Resistance Monitoring of Corynespora cassiicola to Diethofencarb and Procymidone

为明确我国山东和辽宁地区多主棒孢菌对乙霉威和腐霉利的抗药性现状,采用菌丝生长速率法,测定了多主棒孢菌对乙霉威和腐霉利的敏感性,建立了敏感基线;采用区分剂量法,测定了多主棒孢菌对乙霉威和腐霉利的抗药性。结果表明,乙霉威和腐霉利对多主棒孢敏感菌株的平均EC50值分别为(0.22±0.06)μg·mL^(-1)和(2.75±0.91)μg·mL^(-1),两者的敏感性频率均呈连续性单峰曲线,总体呈正态分布,可作为多主棒孢菌对乙霉威和腐霉利的敏感基线。对采集自山东和辽宁地区的828株多主棒孢菌进行抗性水平监测,发现多主棒孢菌对乙霉威和腐霉利的抗性水平不断升高,山东地区多主棒孢菌对乙霉威和腐霉利抗性频率从2017年的58.06%和43.55%上升到2021年的91.30%和78.99%,辽宁地区多主棒孢菌对乙霉威和腐霉利抗性频率从2017年的67.44%和53.49%上升到2021年的82.14%和83.33%。表明多主棒孢菌对乙霉威和腐霉利具有高度的抗性风险,建议在黄瓜生产中乙霉威和腐霉利与其他类型杀菌剂交替或者混合应用,延缓抗药性的发展。

In order to determine the resistance level of Corynespora cassiicola from different regions(Shandong and Liaoning)to diethofencarb and procymidone,in this experiment,the mycelial growth rate method was used to determine the sensitivity of C.cassiicola to diethofencarb and procymidone and the sensitive baselines of C.cassiicola to diethofencarb and procymidone were established.The resistance of C.cassiicola to diethofencarb and procymidone were detected with discriminating dose method.The results showed that the mean EC50 value of C.cassiicola to diethofencarb was(0.22±0.06)μg·mL^(-1) and the mean EC50 value of C.cassiicola to procymidone was(2.75±0.91)μg·mL^(-1).The sensitivity frequencies of both showed a continuous unimodal curve,overall following a normal distribution,which can serve as a sensitive baseline for the sensitivity of C.cassiicola to diethofencarb and procymidone.By monitoring the resistance level of 828 C.cassiicola isolates,it was found that the resistance level of C.cassiicola to diethofencarb and procymidone is continuously increasing.The level of resistance of strains in Shandong to diethofencarb and procymidone increased from 58.06%and 43.55%in 2017 to 91.30%and 78.99%in 2021.The level of resistance of strains in Liaoning to diethofencarb and procymidone increased from 67.44%and 53.49%in 2017 to 82.14%and 83.33%in 2021.It indicates that C.cassiicola has a high resistance risk to diethofencarb and procymidone.It is recommended to alternate or mix the application of diethofencarb and procymidon with other types of fungicides in cucumber production to delay the development of resistance.