云南小菜蛾对Bt的抗药性及盆栽药效评价

Resistance of Plutella xylostella to Bacillus thuringiensis in Yunnan Province and control efficacy of Bt on potted plants

2008-2012年,采用浸叶法连续5年测定了云南省2个主要蔬菜种植区通海县和弥渡县的小菜蛾田间种群对Bt制剂的抗药性,并进行了盆栽药效评价.结果表明,两地区小菜蛾对Bt制剂均表现为低抗或无抗性,抗药性无明显上升趋势.比较了在光照培养箱和自然条件下3种不同Bt制剂对通海和弥渡县小菜蛾盆栽药效,药后第5天通海和弥渡小菜蛾种群在恒温（25±1℃,RH65％～70％）和自然条件下（12～28℃,RH50％～75％）的校正死亡率分别为88.3％～95.5％和80.2％～90.6％、78.8％～89.1％和73.4％～85.7％,两者差异不显著.云南小菜蛾种群对Bt制剂均有较高的敏感性,可在十字花科蔬菜生产中有选择地使用.

Two field populations of Plutella xylostella （diamondback moth,DBM） were collected from Tonghai and Midu counties of Yunnan Province during 2008-2012.Resistance of the two populations to Bacillus thuringiensis （Bt） was tested by leaf-dipping method and control efficacy of Bt formulations on DBM was evaluated on potted plants.The results showed that low level resistance or no resistance was developed in the two populations and no obvious increase of resistance was detected either.Control efficacies of three kinds of Bt formulations on the two populations were evaluated by pot experiment conducted under natural condition （12-28 ℃,RH 50%75%） and indoor constant temperature （25±-1 ℃,RH 65%-70%） in laboratory.Corrected mortalities of Tonghai and Midu populations five days after treatment under constant temperature and natural condition were 88.3%-95.5% and 80.2%-90.6%,78.8%-89.1% and 73.4%-85.7%,respectively,and there was no significant difference between the two treatments.The results indicate that P.xylostella in Yunnan Province is sensitive to Bt and Bt can be recommended to use in cruciferous production in the fields.