常用杀虫剂对菜蛾绒茧蜂的影响及毒理机制研究

田间采集试虫室内测定结果表明,敌敌畏、灭多威和杀虫双对菜蛾绒茧蜂Apanteles plutellae高毒,乙酰甲胺磷对绒茧蜂毒性较低,而氰戊菊酯、氯氰菊酯、氟虫腈、阿维菌素、定虫隆和Bt则是低毒的。菜蛾绒茧蜂AChE的Km及Vmax值分别是小菜蛾的0.22和2.08倍,AChE对敌敌畏的敏感性(K/em>i值)分别是小菜蛾的10.37倍。100 mg/L的胡椒基丁醚(PB)或磷酸三苯酯(TPP)均可使氰戊菊酯明显增效,其中PB的增效作用显著高于TPP。体内抑制实验结果表明,PB和TPP对绒茧蜂AChE活力无显著影响,低浓度(100 mg/L)的PB即可显著抑制绒茧蜂的α-NA和β-NA CarE活力,且抑制率高于TPP,TPP仅在高浓度(1 000 mg/L)时对绒茧蜂的两种CarE活力有显著抑制作用。由此推断,与小菜蛾相比,菜蛾绒茧蜂对有机磷的高敏感性与其显著较高的AChE敏感性有关;此外,多功能氧化酶的解毒代谢在菜蛾绒茧蜂对氰戊菊酯的耐药性中具重要作用。     

寄主抗药性对菜蛾绒茧蜂寄生能力的影响

考察了在使用氰戊菊酯的条件下 ,小菜蛾抗药性对菜蛾绒茧蜂寄生能力的影响。在杀虫剂作用下 ,用抗性寄主饲养的菜蛾绒茧蜂RRC品系对抗性寄主RRP品系幼虫的寄生率达89% ,寄主幼虫死亡率仅 5% ,比RRC对小菜蛾敏感品系SSP幼虫寄生时、或用SSP饲养的菜蛾绒茧蜂SSC品系对SSP寄生时的寄生率显著要高 ,寄主死亡率显著要低。表明杀虫剂存在时 ,寄主抗药性使其具较高存活率而给寄生蜂提供更多的寄主 ,有利于寄生蜂的繁衍。方差分析结果显示 ,小菜蛾品系及蛾×蜂互作对供试小菜蛾幼虫的被寄生率及死亡率均有显著影响 ,表明小菜蛾抗性改变了其对菜蛾绒茧蜂的适合性     

寄主密度、寄生蜂密度和寄生蜂性比对麦蛾茧蜂繁殖的影响

麦蛾茧蜂是鳞翅目昆虫的一种外寄生蜂,是仓储鳞翅目害虫的重要寄生性天敌。为提高麦蛾茧蜂的扩繁效率,本文在室内条件下研究了其寄主烟草粉螟密度、麦蛾茧蜂密度和性比对其子代出蜂数(雌蜂数、雄蜂数和总蜂数)和雌雄性比的影响。结果表明,当烟草粉螟密度为5头/盒时,麦蛾茧蜂的子代出蜂雌蜂数、雄蜂数、总蜂数和雌雄性比最高,分别为(90.71±2.01)、(51.70±2.95)、(142.00±3.88)头和(1.79±0.11);当烟草粉螟密度为50头/盒而麦蛾茧蜂密度不同时,4对寄生蜂(蜂与害虫比为1∶12.5)的平均单雌出蜂数最高;此外,增加雌蜂数显著提高子代出蜂数,而增加雄蜂数并未显著影响这些指标。因此,本文推荐在麦蛾茧蜂的大量饲养中,按寄生蜂、害虫比为1∶5~1∶12.5、寄生蜂雌雄性比为1∶1的方式接蜂且可连续使用10 d,这将有利于麦蛾茧蜂的大量饲养。该研究结果可为麦蛾茧蜂的规模化繁育和应用提供技术参数。     

菜蛾绒茧蜂对几种挥发性物质的定向行为

笔者采用Y型管嗅觉仪法和培养皿法,研究菜蛾绒茧蜂 Cotesia plutellae对挥发物的定向行为反应,并探讨学习经历对菜蛾绒茧蜂寻找寄主能力的影响,以及触角在寄主定向中的作用.     

田间菜蛾绒茧蜂对有机磷敏感性监测及毒理机制分析

对甲胺磷敏感性的田间监测结果显示,绒茧蜂存在着抗性演化,毒力生物测定结果与AChE的K_i值的监测结果呈明显的相关性,每年9月至次年2月期间AChE敏感性最低,8月期间敏感性最高。甲胺磷可显著地抑制绒茧蜂AChE、CarE和GSTs的活性。PB和TPP对AChE的活体抑制率极低,但PB可强烈抑制CarE的活性,而TPP仅在高浓度时对CarE有较显著的抑制作用,PB对甲胺磷有显著的增效作用,而TPP对甲胺磷无增效作用。AChE的K_m、V_(max)及K_i值研究结果表明,田间绒茧蜂对有机磷和氨基甲酸酯的抗性与AChE对杀虫剂的不敏感性有关。由此认为,绒茧蜂对有机磷的抗性主要与其最重要的靶标酶AChE的敏感性改变及多功能氧化酶有关。     

影响两种蚜茧蜂日产卵量因素的研究

本文以桃蚜为寄主,研究了寄主密度、接蜂时间和环境温度对烟蚜茧蜂、菜蚜茧蜂的日产卵量及寄生率的影响。结果表明3种因素均对两种蚜茧蜂的产卵量有不同程度的影响。两种蚜茧蜂的日产卵量随寄主密度增加而增加,在27～32℃时,烟蚜茧蜂雌蜂活动频繁,羽化后第一天的产卵量多于低温(≤23℃)下的产卵量,从第二天起日产卵量下降,说明持续高温不利于雌蜂产卵。本研究认为:人工繁殖烟蚜茧峰时,温度为23℃,寄生蜂与寄主比为1:100的条件较为适宜。     

草地贪夜蛾幼虫日龄及取食的食物对淡足侧沟茧蜂寄生效果的影响

为评估淡足侧沟茧蜂对草地贪夜蛾的防控效果,在室内环境条件下,研究了草地贪夜蛾幼虫寄主日龄和所取食食物对淡足侧沟茧蜂寄生效果的影响。结果表明,无论草地贪夜蛾幼虫取食人工饲料或玉米叶片,淡足侧沟茧蜂对3日龄和5日龄寄主幼虫的寄生率、结茧率、出蜂率及对寄主致死率均显著高于8日龄寄主。另外,在同日龄情况下,淡足侧沟茧蜂对取食玉米寄主的寄生率、结茧率以及子代出蜂率均高于寄生于取食人工饲料的幼虫上的相关指标。寄主取食不同食物会影响淡足侧沟茧蜂的寄生效果,且淡足侧沟茧蜂对5日龄草地贪夜蛾幼虫寄生效果较好。本结果可为室内条件下利用草地贪夜蛾幼虫扩繁淡足侧沟茧蜂,以及应用淡足侧沟茧蜂对草地贪夜蛾进行田间防控提供理论依据。     

绒茧蜂研究进展

绒茧蜂是多种农林害虫幼虫期的重要天敌,世界记录1300多种。我国大陆记述60种,台湾省27种。本文根据文献资料,分5个部分,综述了绒茧蜂对寄主的选择、寄主生理反应、环境与绒茧蜂的关系、种间竞争关系、杀虫剂对绒茧蜂的影响等方面的研究进展。     

斑痣悬茧蜂对不同龄期斜纹夜蛾幼虫的寄生功能反应

为评估斑痣悬茧蜂Meteorus pulchricornis(Wesmael)对其寄主斜纹夜蛾Spodoptera litura(Fabricius)幼虫的寄生作用,在室内研究了斑痣悬茧蜂对2、3和4龄斜纹夜蛾幼虫的寄生功能反应和搜寻效率。结果表明斑痣悬茧蜂对不同龄期斜纹夜蛾幼虫的寄生功能反应均符合HollingⅡ型模型的预测,对3龄寄主幼虫的攻击率大于对2龄寄主,对后者的攻击率又大于对4龄寄主幼虫的攻击;寄主处理时间随寄主龄期增大而延长。此外,斑痣悬茧蜂的搜寻效率随寄主密度增加逐渐降低,相同寄主密度下,斑痣悬茧蜂对2、3龄寄主幼虫的搜寻效率均高于对4龄寄主幼虫的搜寻。研究结果说明,斑痣悬茧蜂对斜纹夜蛾低龄幼虫的寄生作用大于对高龄幼虫的寄生。     

温度和外源激素对白蜡吉丁肿腿蜂翅型分化的影响

为探讨影响寄生蜂翅型分化的环境因素,促进天敌昆虫的利用,在室内比较了白蜡吉丁肿腿蜂Sclerodermus pupariae在21、24、27、30℃和33℃5个温度条件下翅型分化情况,并在24℃下通过对该蜂寄主麻竖毛天牛Thyestilla gebleri幼虫注射早熟素Ⅱ和蜕皮激素,比较不同激素处理对寄生蜂子代雌蜂有翅率的影响。研究结果表明,白蜡吉丁肿腿蜂在27℃和30℃下子代雌蜂的有翅率显著高于其他温度,分别高达62.02%和68.04%。24℃下该蜂雌蜂有翅率最低,仅为0.97%,确定24℃为该蜂的无翅型温度T_(wl)。在T_(wl)下早熟素Ⅱ处理寄主幼虫显著提高了寄生蜂子代雌蜂的有翅率(15.62%)。而用3种浓度的蜕皮激素溶液处理寄主幼虫,其育出的寄生蜂子代翅型均无显著分化,蜕皮激素对白蜡吉丁肿腿蜂的翅型分化无显著影响。在对白蜡吉丁肿腿蜂人工繁育过程中,建议将饲养温度设置为30℃来提高该蜂种群的雌蜂有翅率。结合早熟素Ⅱ具有翅化效应的结果,可以对寄主幼虫进行早熟素Ⅱ处理或者直接在幼期处理子代蜂,从而实现对该天敌资源的高效利用。     

Insecticide susceptibility of surviving Cotesia plutellae (Hym: Braconidae) and Diaeretiella rapae (M'Intosh) (Hym: Aphidiidae) as affected by sublethal insecticide dosages on host insects

The effects of sublethal dosages of insecticides applied to Plutella xylostella L. (Lepidoptera: Yponomeutidae) and Lipaphis erysimi Kaltenbach (Homoptera: Aphidiidae) on the insecticide susceptibility of the surviving endoparasitoids, Cotesia plutellae Kurdjumov (Hymenoptera: Braconidae) and Diaeretiella rapae (M'Intosh) (Hymenoptera: Aphidiidae), were studied in Shangjie, Minhou, China. The susceptibility to methamidophos and the sensitivity of acetylcholinesterase (AChE) to methamidophos and dichlorvos in the adults of host insects were substantially lower than those in the two parasitoids. The host insects were treated with sublethal dosages of methamidophos in P. xylostella and of methamidophos and avermectin in L. erysimi. The cocoon formation in the two parasitoids decreased significantly, from 35.0% (control) to 13.0% (with methamidophos treatment) for C. plutellae; from 20.6% (control) to 9.0% (with methamidophos treatment) and from 24.3% (control) to 16.7% (with avermectin treatment) for D. rapae. The susceptibility to methamidophos of the resultant emerging adults of the two parasitoids was found to be significantly lower than that of the control when the parasitoids were left in contact with the same dosages of methamidophos. The average AChE activity inhibition by methamidophos and dichlorvos in 34-60 adults of the two parasitoids that emerged from the treatments (15.1% and 31.8% respectively for C. plutellae, and 21.1% and 26.9% for D. rapae) was also significantly lower than those of the controls (55.4% and 48.3% respectively for C. plutellae, and 42.9% and 51.7% for D. rapae). The bimolecular rate constant (k(i)) values of AChE to methamidophos and dichlorvos in the adults of parasitoids without the insecticide treatment were 1.78 and 1.56 times as high as those that emerged from the host insects treated with methamidophos for C. plutellae, and 1.91 and 1.66 times as high as those in the case of D. rapae. It is suggested that there is a difference in AChE sensitivity to insecticides between the resultant emerging parasitoids with and without insecticide pretreatment. Furthermore, the introduction of the insecticides to the host insects could be an important factor in the insecticide resistance development of the endoparasitoids. The natural selectivity would favour the parasitoids that had developed an insensitivity to the insecticide(s).     

杭州郊区小菜蛾寄生昆虫调查

１９８９～１９９６年,在杭州郊区调查了十字花科蔬菜小菜蛾的寄生昆虫天敌种类和被寄生率,共发现６种原寄生天敌,即赤眼蜂Ｔｉｃｈｏｇｒａｍｍａ．ｓｐ．菜蛾绒茧蜂Ｃｏｔｅｓｉａｐｌｕｔｅｌｌａｅ,颈双缘姬蜂Ｄｉａｄｒｏｍｕｓｃｏｌｌａｒｉｓ,菜蛾啮小蜂Ｏｏｍｙｚｕｓｓｏｋｏｌｏｗｓｋｉｉ,螟蛉埃姬蜂Ｉｔｏｐｌｅｔｉｃｎａｒａｎｙａｅ,无脊大腿小蜂Ｂｒａｃｈｙｍｅｒｉａｅｘｃａｖｉｎａｔａ．以及７种菜蛾绒     

小菜蛾和绒茧蜂乙酰胆碱酯酶对甲胺磷和甲基异柳磷敏感性监测

对 ACh E的 K m、Vmax和 Ki值的研究结果表明 ,田间小菜蛾和绒茧蜂对甲胺磷和甲基异柳磷的抗性与 ACh E对杀虫剂的不敏感性有关。田间监测结果表明 ,每年 9月至次年 2月期间 ,由于田间杀虫剂选择压较高 ,小菜蛾 ACh E对有机磷较不敏感 ,而在每年的 6月至 8月期间 ,ACh E敏感性有所升高 ,达到全年的最高点。寄生于同一虫源的绒茧蜂 ACh E敏感性的变化也呈明显的相关性。绒茧蜂 ACh E的敏感性显著高于小菜蛾 ,尚未达到高度不敏感水平。当田间选择压极高时 ,可导致小菜蛾 ACh E呈高度不敏感 ,此时绒茧蜂 ACh E也表现出较高的不敏感性。     

Evaluation of selective toxicity of five pesticides against Plutella xylostella (Lep: Plutellidae) and their side-effects against Cotesia plutellae (Hym: Braconidae) and Oomyzus sokolowskii (Hym: Eulophidae)

The toxicities of five pesticides commonly used in vegetable fields to the larvae of the diamondback moth, Plutella xylostella (L) and its two major parasitoids, Cotesia plutellae (Kurdjumov) and Oomyzus sokolowskii (Kurdjumov), were evaluated in the laboratory using several bioassays. When tested at the rates recommended for field application by the manufacturer, fipronil, avermectin and chlorfluazuron produced over 95% mortality on third-instar larvae of P xylostella, but fenvalerate and methomyl did not produce any substantial mortality to such larvae, and over 70% of P xylostella larvae could still pupate normally after feeding on cabbage leaf treated with the two pesticides. In a residual contact assay with adult parasitoids, fipronil and methomyl caused over 93% mortality within 24 h; fenvalerate killed approximately 55% of the adults within 24 h; avermectin and chlorfluazuron showed differential toxicity to the two parasitoids. Avermectin was extremely harmful to O sokolowskii but slightly toxic to C plutellae, while chlorfluazuron was more toxic to C plutellae than to O sokolowskii. In the residue assay with cocoons of C plutellae and pupae of O sokolowskii developed within P xylostella pupae, treatments with pesticides did not reduce adult emergence. However, the mortality of C plutellae adults emerged from the fipronil-treated cocoons increased greatly within 24 h post-emergence; adults from the fenvalerate-treated cocoons parasitized less host larvae. Treatments with fenvalerate and methomyl significantly increased the mortality of O sokolowskii adults within 24 h post-emergence. Recommendations of choosing pesticides for the control of P xylostella are given.     

阿维菌素对十字花科蔬菜主要害虫的生物活性及防治小菜蛾、菜青虫的田间应用研究

室内毒力测定表明,阿维菌素对菜青虫、小菜蛾、菜蚜有很高的毒力,LC50分别为0.022、0.12和0.28 mg/L;对甜菜夜蛾和斜纹夜蛾的毒力较差,LC50分别为67.56和165.73 mg/L。阿维菌素不影响小菜蛾卵的孵化率。小菜蛾幼虫随虫龄增大,对阿维菌素的敏感性下降。田间试验表明,阿维菌素4 mg/L和8 mg/L对菜青虫和小菜蛾的防效在95%以上,持效期10~15 d。阿维菌素与高效氯氰菊酯(1∶6)、与杀虫单(1∶299)复配对小菜蛾防治有显著的增效作用和良好的田间效果。     

沼液对韭菜迟眼蕈蚊的防治效果

通过室内选择性测定和田间试验,评价了沼液对韭菜迟眼蕈蚊的防治效果。结果表明,沼液对韭菜迟眼蕈蚊表现出一定的驱避活性,对幼虫的驱避率、拒食率分别达55.30%、53.81%,雌雄成虫选择反应率分别为33.2%、30.5%,对雌虫产卵驱避率为36.82%。田间试验结果表明,以沼液∶水(1∶1)处理幼虫、成虫,随着时间的延长防效逐渐提高,处理后45d防效达到最大,分别为43.16%、56.50%。     

Susceptibilities to methamidophos and enzymatic characteristics in 18 species of pest insects and their natural enemies in crucifer vegetable crops

The susceptibilities to methamidophos as well as the kinetic and inhibitory parameter of acetylcholinesterases (AChE) and the activities of carboxyestsrases (CarE) and glutathione-S-transferases (GST) were studied in 18 species field populations of insects collected in Fuzhou, China during April and May 2000 and 2001. The insect species included five hymenopteran endoparasitoids, one hymenopteran exoparasitoid, one hymenopteran hyperparasitoid, one dipteran predator, four coleopteran predator ladybirds, six herbivorous pest insects of lepidoptera, diptera, homoptera, and coleoptera, respectively. There existed significant correlations between the susceptibility to methamidophos and the k_i values of AChE to methamidophos, dichlorvos, and carbofuran and between the k_i and V_max values of AChE among 18 species of insects. The six herbivorous pests and four ladybirds showed significantly low k_i and V_max values of AChE compared to the seven parasitoids and predator Epistrophe balteate. It was difficult to correlate the susceptibility to methamidophos or the k_i values with the K_m values of AChE, or with the activity of CarE and GST. The activities of CarE and GST varied depending on the different insect species. Significant synergisms of piperonyl butoxide (PB), triphenyl phosphate (TPP), and diethyl maleate (DEM) with methamidophos were observed in 14 pest insects and their natural enemies. Synergisms of PB were found to be the greatest. Reduced k_i values suggested that insensitive AChE might play a critical role in the tolerance to methamidophos in the 18 insect species. The detoxification enzymes, mixed-function oxidase (MFO), CarE, and GST, were believed to be involved in the tolerance to methamidophos. MFO might play the most important role, and CarE or GST might be important in the tolerance in some insect species. Different models of tolerance to methamidophos and enzymatic potential were existed in parasitoids, predators, and herbivores based on the different selection of insecticide pressure (either directly by exposing to the spray in the field, or indirectly by the insecticides penetrated into the body of host insects) as well as different ecological and biological habitats.     

多杀菌素对菜蛾绒茧蜂的致死和亚致死效应

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。