苏云金芽胞杆菌G033A对三种赤眼蜂寄生番茄潜叶蛾能力的影响

Effect of Bacillus thuringiensis G033A on the Ability of Three Trichogramma Species to Parasitize Tuta absoluta

为探究苏云金芽胞杆菌G033A(Bt G033A)对番茄潜叶蛾不同龄期幼虫的毒力大小及对赤眼蜂寄生番茄潜叶蛾能力的影响,本研究采用浸叶法和饲料混毒法分别对番茄潜叶蛾及三种赤眼蜂进行处理,测定了Bt G033A对番茄潜叶蛾不同龄期幼虫和三种赤眼蜂成虫的室内毒力,同时分析Bt G033A对三种赤眼蜂寄生量及功能反应的影响。结果表明,BtG033A对番茄潜叶蛾1龄幼虫、2龄幼虫、3龄幼虫、4龄幼虫的LC50分别为25.381、19.537、17.406和15.772 g/L,而对三种赤眼蜂均为低毒。在Bt G033A田间推荐浓度处理后,虽然玉米螟赤眼蜂、螟黄赤眼蜂、松毛虫赤眼蜂对番茄潜叶蛾卵的寄生功能反应模型仍符合HollingⅡ型,但三种赤眼蜂的寄生能力均有所降低。其中,玉米螟赤眼蜂在药剂对照组的寄生量(25粒/皿:18.600粒)、处理猎物时间(0.012d)、控害效能(84.833)、日寄生上限(83.333粒)和搜寻效应均表明其对番茄潜叶蛾的寄生能力强于螟黄赤眼蜂和松毛虫赤眼蜂。此外,在药剂处理后,玉米螟赤眼蜂各项寄生参数同样优于其他两种赤眼蜂。因此,玉米螟赤眼蜂可作为番茄潜叶蛾的优选寄生性天敌之一,并可联合Bt G033A对番茄潜叶蛾进行协同防控。

Toxicity of Bacillus thuringiensis G033A(Bt G033A)to different instar larvae of Tuta absoluta and effect of Bt G033A on the ability of three Trichogramma species to parasitize T.absoluta were determined by leaf dipping method and feed mixed toxicity method,respectively.The results showed that the LC50 of Bt G033A to the 1st,2nd,3rd,and 4th instar T.absoluta larvae were 25.381,19.537,17.406,and 15.772 g/L,respectively,while Bt G033A was low toxic to the three Trichogramma species.Although the parasitic functional responses of T.ostriniae,T.chilonis and T.dendrolimi to T.absoluta eggs conformed to the Holling II model,the parasitic ability of the three Trichogramma species decreased post treatment with the recommended concentration of Bt G033A in the field Among them,the parasitism amount(25 eggs/dish:18.600 eggs),prey treatment time(0.012 d),pest control efficiency(84.833),daily parasitism upper limit(83.333 eggs),and prey search efficiency of T.ostriniae in the control group showed that T.ostriniae was superior to T.chilonis and T.dendrolimi.Likewise,T.ostriniae showed higher post-treatment parasitic performance than t the other two Trichogramma species.Therefore,T.ostriniae can be used as one of the high-potential parasitic natural enemies of T.absoluta and can applied in combination with Bt G033A in biocontrol of T.absoluta.