两种有机硅助剂对四氯虫酰胺防治菜青虫的增效作用

为明确两种有机硅助剂Silwet 408和Greenwet 7618对四氯虫酰胺防治菜青虫的增效作用,本文采用喷雾法测定四氯虫酰胺以推荐剂量、50%推荐用量分别与Silwet 408和Greenwet 7618的3 000倍稀释液混用对菜青虫的田间防效。结果表明,四氯虫酰胺以50%推荐用量分别与Silwet 408和Greenwet 7618混用,药后3 d对菜青虫的防效均与单独使用推荐剂量的防效无显著差异;药后7 d,50%推荐用量与Greenwet 7618混用对菜青虫的防效与推荐剂量的四氯虫酰胺仍无显著差异,而50%推荐用量与Silwet 408混用的防效显著降低;在药后14 d,所有处理对菜青虫无防治效果。因此,建议在生产上推广50%推荐用量的四氯虫酰胺与Greenwet 7618的3 000倍液混用防治菜青虫。     

PrGV多角体膜蛋白（PEP）的分析

【目的】对菜粉蝶颗粒体病毒(Pieris rapae Granulovirus,PrGV)多角体膜蛋白(polyhedron envelope protein,PEP)进行研究,为揭示PEP的功能及其在病毒生命过程中的作用提供参考。【方法】以PrGV PEP为对象,通过序列分析、原核表达、抗体制备、Western blotting、胶体金免疫定位、实时荧光定量PCR等方法初步确认该基因定位和表达时相。【结果】PrGV PEP与其他鳞翅目昆虫颗粒体病毒的PEP同源性达到50%左右,但未在核型多角体病毒(Nucleo polyhedro virus,NPV)中发现同源序列。定量PCR分析表明,菜青虫感染PrGV后24h可检测到PEP的存在,随后该基因的表达水平逐渐升高,并在72h达到峰值。通过Western blotting可以在感染PrGV的菜青虫体内检测到大小分别为23ku和15ku的清晰条带,说明制备的多克隆抗体具有较好的特异性。免疫金标记将PEP定位于椭圆型的颗粒体,证明PEP是GV包涵体的重要组成部分。【结论】PrGV PEP在颗粒体病毒中较为保守,可能是PrGV晚期表达的重要基因,参与病毒侵染后期颗粒体结构的形成。     

甘肃天然草地30种有毒植物提取物对菜粉碟幼虫的拒食和触杀作用研究

采用虫体浸渍法和叶碟浸渍法测定了甘肃天然草地30种有毒植物提取物对菜粉蝶4龄幼虫的拒食和触杀作用。结果表明,铁棒锤、贝加尔唐松草、灰绿黄堇、黄帚橐吾、冷蒿(小白蒿)、骆驼蓬和狼毒甲醇提取物对菜粉蝶4龄幼虫具有很强的拒食和触杀作用,48 h的拒食率为82.23%~100.00%,触杀死亡率为80.00%~94.12%;露蕊乌头、青藏大戟、狼毒大戟和泽漆甲醇提取物具有很强的拒食作用,48 h的拒食率为95.14%~97.62%。综合分析,铁棒锤、贝加尔唐松草、灰绿黄堇、黄帚橐吾、冷蒿(小白蒿)、骆驼蓬、狼毒、露蕊乌头、青藏大戟、狼毒大戟和泽漆11种有毒植物具有研究和开发利用价值。     

Effects of different brassicaceous host plants on the fitness of Pieris brassicae (L.)

Pieris brassicae (L.) is a destructive cosmopolitan pest of cruciferous crops. It is present wherever its host plants occur and it is considered to be one of the most widely distributed of all the Lepidoptera. We investigated the affect of various host plants on the fitness of P. brassicae to survive, develop and reproduce. We quantified development time, survival and mortality on cabbage (Brassica oleracea capitata), cauliflower (Brassica oleracea botrytis), radish (Raphanus sativus), broccoli (Brassica oleracea italica), and mustard (Brassica campestris) under laboratory conditions. The developmental time from eggs to adult eclosion was the shortest (30.3 days) on cabbage and the longest (38.0 days) on radish. However, adult longevity was significantly (P < 0.001) greatest on cabbage compared with the other host plants tested. Similarly, the developmental rate of P. brassicae was found to be faster on cabbage than other cole crops. Moreover, the lowest immature mortality was evident on cabbage and highest on mustard and radish. Differences in reproductive parameters of the P. brassicae among host plants were analyzed using pseudo-values, which were produced by jackknife re-sampling. The data showed that the higher intrinsic rate of natural increase (0.116 females/female/day) was found on cabbage. Cabbage was recognized as the most suitable host for P. brassicae because of shorter developmental period, higher percentage survival, lower doubling time (6.00), and higher number of adult emergence (29.7%).     

Toxic effects of neem-based insecticides on Pieris brassicae (Linn.)

Four neem-based insecticides, Neemix^® (0.25% EC @ 20 mg azadirachtin/liter), Ecozin^® (3% EC @ 20 mg azadirachtin/liter), Agroneem^® (0.15% EC @ 4.8 mg azadirachtin/liter) and Neem oil (0.25% EC azadirachtin @ 20 mg azadirachtin/liter) and a non-commercial neem leaf powder, were evaluated for oviposition deterrence, antifeedant effect to larvae and toxicity to eggs and larvae of Pieris brassicae (Linn.) on cabbage leaves in the laboratory. The concentrations tested were with in the ranges of recommended field rates. Oviposition deterrence in no-choice, two-choice and six-choice assays, was observed for all the treatments. They exhibited significant (P < 0.01) oviposition deterrence on P. brassicae when compared with a non-treated control. Cabbage leaves treated with the neem-based insecticides were used as an egg-laying substrate. Numbers of eggs oviposited by P. brassicae adults on treated cabbage leaves were significantly lower then those treated with water, but no significant differences were detected among the neem insecticides. They also deterred feeding by Pieris larvae and exhibited significant antifeedant effects. Larvae of P. brassicae on treated leaves stopped feeding and dropped from the leaf, resulting in no or minimal damage. Direct contact with neem-based insecticides decreased the survival of eggs. Survival of larvae fed for 9 days on leaves treated with neem-based insecticides was reduced to 51%, 49%, 48%, 24% and 18% in the Neem oil, Neemix, Agroneem, Ecozin and neem leaf powder treatments, respectively. Therefore, it can be concluded from the present investigations that neem-based insecticides had oviposition deterrence, antifeedant and toxic effect to P. brassicae.     

利用酶抑制—比色法检测5种蔬菜中农药残留

运用酶抑制—比色法,以菜青虫乙酰胆碱酯酶作为试验酶源,测定了四川雅安地区的四季豆、生菜、凤尾等5种蔬菜中乐果的残留量。结果表明,生菜乙醇萃取液的农药残留量最大,达到4.209 3mg/kg,超过国家标准(1 mg/kg);凤尾农药残留量最低,其乙醇萃取液的农药残留量为0.043 8 mg/kg。此法对农药残留快速检测有一定的实践意义。     

博落回提取物对菜粉蝶幼虫的拒食活性

[目的]测定博落回提取物对菜粉蝶5龄幼虫的拒食活性。[方法]采用叶碟法,分别就博落回植物不同部位对菜粉蝶5龄幼虫的拒食活性进行了测定。[结果]当菜粉蝶5龄幼虫取食用0．400％的博落回整株植物的乙醇提取物处理过的叶碟24和48h后的选择性拒食率分别为87．50％和89．56％。当菜粉蝶5龄幼虫分别取食用1．000％的博落回植物根、茎、叶乙醇提取物处理过的叶碟后,24h的非选择性拒食率分别为91．78％、91．01％、90．63％,48h的拒食率分别为89．33％、88．91％、86．76％。[结论]博落回植物提取物对菜粉蝶5龄幼虫有很强的拒食活性。     

几种非十字花科蔬菜提取物对菜青虫的干扰控制作用

研究了9种非十字花科蔬菜乙醇提取物对菜青虫种群的干扰控制作用。结果表明:9种非十字花科蔬菜提取物对菜青虫成虫产卵都有较好的忌避作用,但对卵和低龄幼虫的毒杀作用不明显。其中茼蒿、大蒜和番茄对菜青虫种群的干扰控制作用较好,干扰作用控制指数分别达到0.0965、0.1166和0.0557,即控制效果分别达到90.35%、88.34%和94.43%。     

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%。