【作者】 胡菡青；

【导师】 尤民生；

【作者基本信息】 福建农林大学 ， 农业昆虫与害虫防治， 2003， 硕士

【摘要】 本文系统调查了小菜蛾主要寄生蜂及菜蛾绒茧蜂的重寄生蜂种类，并研究了Bt制剂对小菜蛾幼虫的毒力及生物学特征的影响、对小菜蛾主要寄生蜂的毒性及菜蛾绒茧蜂的潜在影响。此外，还研究了菜蛾绒茧蜂和Bt制剂对小菜蛾的单独与联合控制作用和寄生对小菜蛾幼虫生理生化方面的影响。结果如下： (1)通过近1年的田间或温室调查，发现小菜蛾主要寄生蜂种类4种，即东方长颊姬蜂Macromalon orientale Kerrich、菜蛾绒茧蜂Cotesia plutellae Kurdjumov、菜蛾啮小蜂Oomyzus sokolowskii Kurdjumov和大腿小蜂Brachymeria sp．；菜蛾绒茧蜂的主要重寄生蜂3种，即菜蛾啮小蜂Oomyzus sokolowskii Kurdjumov，金小蜂Trichomalopsis sp．和次生大腿小蜂Brachymeria secundaria Ruschka； (2)毒力测定结果表明，7种Bt制剂对小菜蛾3龄幼虫的毒力高低依次为，绿茵＞高效Bt／杀虫单＞Bt可湿性粉剂＞苏泰＞农泰＞ABG-6444＞比力Bt(8010)浓缩型粉剂；Bt可湿性粉剂对小菜蛾不同虫龄幼虫的毒力随着虫龄的增长而降低，不同虫龄之间差异显著；Bt可湿性粉剂能显著降低小菜蛾化蛹率和成虫羽化率及成蛾产卵量和寿命。 (3)Bt制剂对小菜蛾主要寄生蜂的影响 绿茵和苏泰对菜蛾绒茧蜂成蜂和茧来说属于有害类药剂，比力、高效Bt／杀虫单、农泰和ABG-6444属于中度有害类杀虫剂，Bt可湿性粉剂属于无害类药剂；绿茵、高效Bt／杀虫单对菜蛾啮小蜂来说属于有害类药剂，比力和苏泰属于中度有害类杀虫剂，Bt可湿性粉剂、农泰和ABG-6444属于无害类药剂；Bt制剂对东方长颊姬蜂无直接的毒性。 菜蛾绒茧蜂不能区分感病(Bt处理)和健康(Bt未处理)小菜蛾幼虫：当两种处理的小菜蛾幼虫同时存在时，该蜂对它们的选择系数和寄生率差异不显著。 Bt可湿性粉剂使小菜蛾3龄幼虫的发育历期显著延长，部分未死进入4龄的幼虫和蛹，其发育历期较对照略有所延长，但差异不显著；P-Bt和Bt-P处理较P处理略延长了菜蛾绒茧蜂卵产下至结茧的发育历期，其中以P-Bt处理延长最为显著，但各处理间差异不显著；在菜蛾绒茧蜂的不同发育阶段施用Bt使蜂的结茧率下降，但下降幅度在不同发育阶段不同；在P、P-Bt和Bt-P处理下，菜蛾绒茧蜂对小菜蛾幼虫的寄生率差异不显著，其中以Bt-P处理中菜蛾绒茧蜂对小菜蛾的寄生率最高，而对小菜蛾的致死率差异比较显著，其中P-Bt对小菜蛾的致死率最大。 (4)Bt制剂和菜蛾绒茧蜂单独和联合对小菜蛾的控制作用 当Bt制剂与菜蛾绒茧蜂共同作用于小菜蛾时，两者之间的作用是增效的。 (5)小菜蛾幼虫被菜蛾绒茧蜂寄生后生理生化的变化 小菜蛾幼虫在被寄生前期和后期，寄主血淋巴蛋白质浓度显著下降，而在被寄生的中期寄主血淋巴中蛋白质浓度与与未寄生差异不显著。更多还原

【Abstract】 In this paper, main parasitoids of diamondback moth (DBM), Plutella xylostella ( L.) and the bioactivity of Bacillus thuringensis (Bt) against DBM were studied. Investigations were also conducted on the selective toxicity of Bt to main parastitoids of DBM, the effect of Bt on host selection of Costesia plutellae Kurdjumov, sublethal effects of Bt on DBM and the larval parasitoid Costesia plutellae Kurdjumov, the independent and combined effects of Bacillus thuringiensis and Costesia plutellae Kurdjumov on DBM. And the total protein content in haemolymph of parasitized DBM larvae was determined, This research aims to explore the relationship between the two biological control agents to aid controling DBM.The species of the parasitoids on DBM in crucifer fields in the suburbs of Fuzhou were investigated. Four parasitic species, i.e., Macromalon orientate Kerrich, Cotesia plutellae Kurdjumov, Oomyzus sokolowskii Kurdjumov, Brachymerea sp., and three hyperparasitic species, i.e., Brachymeria secundaria Ruschka, Oomyzus sokowskii Kurdjumov, Trichomalopsis sp. were found. Investigation of adult emergence and hyperparasitizing of collected cocoons from field indicated that field parasitic adult emergence rate correlated to next field population, that Oomyzus sokowskii Kurdjumov can emergenced from the Costesia plutellae Kurdjumov pupa, and that the tow peaks of Costesia plutellae Kurdjumov fell on April-May and on the third period of September-the first period of October. During the peaks, Costesia plutellae Kurdjumov was often hyperparasitized and the rates of hyperparasitization reached 25%.The results of bioassay showed that toxicity of Bt preparations against the third larvae of DBM was as follows: luying (LC50=341.119mgL-1) > high effectual Bt/sha chong dang (LC50=406.92mg.L-1)> Bt soluble powder (LC5o=448.168mg.L-1) > sutai (LC50=525.318mg.L-1) (LC50=525.318mg.L-1) >nongtai (LC50=746.068mg.L-1) > ABG-6444(LC50=1989.803mg.L-1) >biliBt(8010) suspension concentration ( LC50=2037.164mg.L-1); The toxicity of Bt soluble powder to the different instar larvae of DBM decreased with the instar development, it indicated great difference among different instar.Bt fed by 4-instar larvae led to the reduction in both the ratio of pupating and adult emergence, which significantly increased with the increase of Bt concentration, When theadult were fed with Bt at concentrations recommended for field application, the longevity of the moth was not affected, but their egg production was reduced significantly.The sensitivity of the main parasitoids of DBM to field concentrations of seven Bt preparations was evaluated by residue film method. Luying is the highest toxic to Oomyzus sokolowskii Kurdjumov, and the linear regression of toxicity was y =0.814+1.9538 x (r=0.984), LC50=140.925079mg.L-1. According to the indexes proposed by Guoyujie (1995.), luying fell into deleterious preparation. Bili (8010) into low toxicity preparation and nongtai and Bt into innocuous preparations; Sutai of seven Bt preparations to Costesia plutellae Kurdjumov was the highest toxic and adult mortality reached 66.67%. After contacting film for one day, bili (8010) was the second highest toxic to Costesia plutellae Kurdjumov. Bt soluble powder, nongtai , Bt/sha chong dang were harmless to Costesia plutellae Kurdjumov.Studies on sublethal effects of Bt soluble powder on Costesia plutellae Kurdjumov suggested that the parasitoid could not distinguish between Bt-treated and untreated larvae of DBM and that Bt had no side-effects on adult emergence and longevity, mean egg production of per parasitoid and insect parasitized per female was not affected.The toxicity of Bt soluble powder on DBM was relatively high, while that to the main parasitoids of DBM was relatively low. Thus Bt soluble powder is selective bio-insecticides in practice.Studies on the independent and combined effects of Costesia plutellae Kurdjumov and Bt suggested that the two methods had synergetic effects.Finally, the total protein content of variey in haemolymph更多还原