云南省马铃薯、番茄晚疫病菌对甲霜灵敏感性及地理分布

用含药平板法对2003年至2005年分离自云南省22个马铃薯和番茄产区的257个马铃薯和番茄晚疫病菌菌株的甲霜灵敏感性进行了系统的测定。结果表明,在11个马铃薯或番茄产区检测到甲霜灵抗性或中抗菌株的马铃薯和番茄晚疫病菌对甲霜灵的敏感性表现出明显的差异,马铃薯晚疫病菌主要由甲霜灵敏感群体组成,而番茄晚疫病菌主要由甲霜灵抗性和中抗群体组成。测定的167个马铃薯晚疫病菌中,甲霜灵抗性、中抗、敏感菌株分别为20.4%、7.2%和72.4%;测定的90个番茄晚疫病菌中,甲霜灵抗性、中抗、敏感菌株分别为56.7%、28.9%和14.4%。马铃薯和番茄晚疫病菌对甲霜灵抗性和中抗菌株在滇中多季作种植区内发生的比例较高。甲霜灵的药效已在云南省的少数马铃薯和大部分番茄产区下降甚至失效,因此,避免长期使用单一的杀菌剂对晚疫病进行防治是非常必要的。

Metalaxyl sensitivity and geographical distribution of Phytophthora infestans on potato and tomato in Yunnan

Metalaxyl sensitivity of 257 isolates of Phytophthora infestans collected from twenty-two potato and tomato production regions in Yunnan from 2003 to 2005 were tested by fungicide-amended petri plates.The result showed that resistant or intermediate resistant isolates of P.infestans were detected in eleven potato or tomato production regions.However,the sensitivity of P.infestans to metalaxyl was obviously different between isolates collected from potato and that from tomato.P.infestans populations from potato were mainly composed of sensitive isolates to metalaxyl and populations from tomato were mainly resistant and intermediate resistant.Among the 167 isolates collected from potato,the ratio of resistant,intermediate resistant and sensitive isolates was 20.4 %,7.2 % and 72.4 %,respectively.Among 90 isolates from tomato,the ratio of resistant,intermediate resistant and sensitive isolates was 56.7 %,28.9 % and 14.4 %,respectively.The frequency of resistant and intermediate resistant isolates from potato and tomato was high in middle multiple cropping zones of Yunnan.The result suggested that the efficiency of metalaxyl to control late blight disease was decreasing,even losing in some potato production regions and most tomato production regions in Yunnan due to occurrence of resistant populations of P.infestans.It was necessary to avoid the situation that sprinkled single fungicide to control late blight disease for a long time.