马铃薯晚疫病菌对甲霜灵的抗性及与霜脲氰和霜霉威交互抗药性的研究

Resistance to Metalaxyl of Phytophthora infestans and Cross-resistance of Metalaxyl with Cymoxanil and Propamocarb

【目的】测定中国马铃薯主产区晚疫病菌对甲霜灵药剂的抗性及频率,并测定霜脲氰和霜霉威与甲霜灵的是否存在交互抗药性;【方法】通过菌落直径法检测马铃薯晚疫病菌对甲霜灵的抗性,通过比较药剂的毒力确定霜脲氰和霜霉威与甲霜灵是否存在交互抗药性;【结果】在测定的4个马铃薯主产省中,除云南省以外,四川、河北和黑龙江等3省均存在马铃薯晚疫病菌对甲霜灵的抗性菌株,其抗性频率分别为16.7%,24.0%和100%。毒力测定表明霜脲氰对甲霜灵抗性菌株和敏感菌株毒力都很强,而霜霉威对这两种菌株的毒力都很差,这说明甲霜灵与霜脲氰和霜霉威不存在交互抗药性;【结论】在中国普遍存在对甲霜灵产生抗性马铃薯晚疫病菌菌株,霜脲氰与甲霜灵不存在交互抗药性且毒力强,可作为甲霜灵的替代药剂防治晚疫病。

[OBJECTIVE]The resistance to metalaxyl of Phytophthora infestans was assessed in the four provinces of main potato production and cross-resistances of metalaxyl with propamocarb and cymoxanil were also examined; [METHOD]The resistance to metalaxyl of P. infestans was assessed by an in vitro radical growth assay on fungicide-amended media and cross-resistances of metalaxyl with propamocarb and cymoxanil were estimated through comparison of virulence of three fungicides; [RESULTS]Metalaxyl-resistant isolates generally occurred in three provinces of Sichuan, Hebei and Heilongjiang provinces except Yunnan and the frequencies of metalaxyl-resistant strains were 16.7%, 24.0% and 100% in Sichuan, Hebei and Heilongjiang provinces, respectively. Tests of virulence of three fungicides shown that virulences of cymoxanil to metalaxyl-resistant and sensitive isolates were very high and virulences of propamocarb to these two kinds of isolates were very low, which indicating cross-resistances of metalaxyl with propamocarb and cymoxanil did not exist; [CONCLUSION]Metalaxyl-resistant isolates of P. infestans generally occurred in China. Cymoxanil could substitute metalaxyl for controlling potato late blight because it was highly virulent to P. infestans and did not exist cross-resistances with metalaxyl.