多杀菌素对菜蛾绒茧蜂的致死和亚致死效应  

Lethal and Sublethal Effects of Spinosad on the Parasitoid Cotesia plutellae

作　　者：李增梅[1] 刘银泉[1] 刘树生[1] 

机构地区：[1]浙江大学应用昆虫学研究所,浙江杭州310029

出　　处：《农药学学报》2005年第1期24-28,共5页Chinese Journal of Pesticide Science

基　　金：国家自然科学基金项目(30300237).

摘　　要：以对多杀菌素高抗的小菜蛾纯合子品系作寄主饲养菜蛾绒茧蜂,用多杀菌素田间推荐使用浓度(25 mg/L)分别处理处于卵期、幼虫期和蛹期的绒茧蜂,其中卵期和幼虫期通过处理寄主幼虫间接处理,并测定该药剂对成虫的毒力,系统观察该杀虫剂对绒茧蜂各虫期的致死和亚致死作用.与对照相比,绒茧蜂卵期或幼虫期其寄主受药后,可导致蜂幼虫死于寄主体内或啮出寄主的过程中,使结茧化蛹率下降43% ～56%,成虫羽化率下降19% ～33%,成蜂雌性比下降11% ～25%,而成虫大小、寿命和寄生力未受显著影响;在蛹期受药使成虫羽化率下降10%,成蜂寿命缩短,但对成虫寄生力无显著影响;对成虫24 h的LC99为4.31 mg/L.结果表明,多杀菌素可进入寄主作用于其体内的蜂卵和幼虫,或直接作用于蜂蛹和成虫,从而对绒茧蜂各个虫态产生显著的致死和亚致死效应,尤以对成虫高毒.Test cohorts of the parasitoid Cotesia plutellae (Hymenoptera: Braconidae) were reared on a strain of the host, Plutella xylostella, with a high level of resistance to the insecticide spinosad. To (observe) the lethal and sublethal effects of the insecticide on various stages of C. plutellae, cohorts of the parasitoid were treated with 25 mg/L spinosad (the recommended rate for field application) at the egg or larval stage by applying the insecticide to the host larvae, or at the pupal stage by direct (application.) In addition, the toxicity of the insecticide on adult wasps was bioassayed. Compared to the controls, when the parasitoids were exposed to spinosad at the egg or larval stage via their host larvae, they suffered (mortality) within the hosts or in the process of egression out of the hosts, resulting in reduction in cocoon formation and pupation by 43%~56%, adult emergence by 19%~33% and adult female ratio by 11%~25%, while adult body size, longevity and ability of parasitism were unaffected; when the parasitoids were exposed to spinosad at the pupal stage, adult emergence was reduced by 10% and adult longevity was decreased, while ability of parasitism of the adult females was unaffected; and the LC_(99) for adults at 24 h tested by residue contact was (4.31 mg/L.) These (results) demonstrate that spinosad can exert toxicity on the parasitoid eggs and larvae following entry to the host larvae, or exert toxicity directly on the (parasitoid) pupae and adults, thereby cause lethal and sublethal effects on all stages of the parasitoid, with the highest acute toxicity to the adult stage.

关 键 词：菜蛾绒茧蜂 小菜蛾 多杀菌素 致死效应 亚致死效应 

分 类 号：Q965.9[生物学—昆虫学]