【作者】 徐德进；

【导师】 祝树德；

【作者基本信息】 扬州大学 ， 农业昆虫与害虫防治， 2005， 硕士

【摘要】 印楝素（Azadirachtin）是从印楝（Azadirachta indica A. Juss）种子中分离出来的高效化合物,对害虫具有拒食、忌避、产卵抑制、生长调节、绝育等多种作用。2001-2003年,通过室内和田间试验,初步探明了印楝素对水稻二化螟的生物活性、作用机制和田间应用技术,结果表明,印楝素是适合于水稻螟虫防治的新型生物农药。本文在此基础上进一步探讨印楝素对水稻褐飞虱的生物活性,并深入研究印楝素对水稻生长发育的影响,同时评价印楝素对几种水生动物和拟水狼蛛的毒性,主要结果如下: 1.系统研究了印楝素对水稻褐飞虱的生物活性,结果表明:印楝素对水稻褐飞虱具有拒食、内吸毒杀、生长调节、抑制繁殖等多种作用方式。经室内管测法测定,印楝素有效成分6、3、1.5、0.75、0.375mg/L处理后24h,褐飞虱3龄若虫的校正拒食率分别为77.65%、67.91%、60.45%、52.18%、44.77%,拒食中浓度AFC₅₀为0.6126mg/L。水稻对印楝素有较强的内吸作用,用6mg/L印楝素溶液浸根4h后,褐飞虱3龄若虫的校正死亡率达76%,12h后,校正死亡率为97.94%。亚致死剂量1、0.5、0.375mg/L处理后,若虫的生长发育受到明显影响,处理3d和7d后,体重增加量和蜜露分泌量均显著减少,1mg/L处理7d后,体重和蜜露分泌分别比对照减少48.08%和62.62%。长翅型和短翅型成虫经0.25、0.375、0.75mg/L的印楝素处理后,产卵量、孵化率均显著减少,同时,导致雌虫寿命和产卵期缩短。室内试验结果表明,印楝素对褐飞虱若虫的触杀作用较弱。 2.通过室内的生物测定和盆栽试验,研究了印楝素对水稻生长的影响。印楝素乳油浸种对水稻种子的发芽率没有影响;但可显著促进稻芽的生长,3mg/L印楝素浸种处理后第4d,芽长比对照增加30.56%;印楝素浸种对种子根的生长有明显的抑制作用,3mg/L处理后第4d,稻种根长在1cm以下的占58.41%的,而对照根长在1cm以下的仅占19.16%;浸种处理后,水稻幼苗地上部分长度明显高于对照,叶片叶绿素含量增加,6mg/L印楝素溶液浸种处理后幼苗叶片的叶绿素a、叶绿素b和总叶绿素含量分别比对照增加了16.73%、28.97%和22.69%。二叶一心期幼苗喷雾试验表更多还原

【Abstract】 Azadirachtin, the most potent compound, was isolated from the seed of the neem tree, Azadirachtia indica A.Juss. It has many modes of function against insects as antifeedant deterrence oviposition inhibitor growth regulator sterilization and soon. In 2001-2003, the biological activity, functional mechanism, technology of field application of the 0.3% azadirachtin emulsion on rice stem borer, Chilo Suppressalis were specially studied. The results showed that azadirachtin was the perfect botanical pesticide which could be used to control rice stem borer. In order to explore the integrated effects of azadirachtin on paddy pests, the bioactivity of Azadirachtin on Brown Planthopper, Nilaparvata lugens Stal was systematically studied in 2004. At the same time, it’s safety on rice plant, aquatic animals(loach, tadpole, filed snail) and paddy field spider, Pirata subpiraticus, was evaluated. The main results were as following:1. Bioactivities of azadirachtin against the nymphs of brown planthopper(BPH) Nilaparvata lugens Stal were specially studied in this paper. Results indicated that azadirachtin had many modes of function against BPH as antifeedant, systemic activity, growth regulator, oviposition inhibitor and so on. The antifeedant rates of BPH nymph reached 77.65%, 67.91%, 60.45%, 52.18% and 44.77% respectively when rice stems were treated with 6, 3, 1.5, 0.75 and 0.375mg/L azadirachtin. The antifeeding median-concentrations (AFC50) for BPH was 0.6126mg/L after being treated with azadirachtin for 24h. Higher systemic insecticidal activity of azadirachtin has been obtained. After rice fibre absorbed 6.00mg/L dilution of azadirachtin for 4h and 12h, the corrected mortality of BPH nymph were 76.00% and 97.94% respectively. When the nymphs of BPH were treated with the sub-lethal dose of azadirachtin, the body weight and honeydew excretion amount were decreased. The body weight and the honeydew amount were decreased by 48.08% and 62.62% respectively as compared to the control, after treating at 1.00 dose for 7days. When the brachybperous and macropterous adults treatedwith the sub-lethal dose of azadirachtin, the number of oviposition and the rate of egg hatching reduced significantly. The longevity of female adults was shorter than the control, while the period of oviposition was shortened.2. Based on the bioactive test in the laboratory under controlled conditions and the potexperiment, the effects of azadirachtin on the rice were studied. The results showed thatazadirachtin had no significant effect on the rice seed germination by soaking treatment.The shoot length was increased, whereas the growth of root was inhibited obviously whenrice seeds soaking with the azadirachtin solution. The shoot length was increased by30.56% as compared to the control. About 58.41% root length were below lcm, while only19.16% in the control. The length of aerial part seedling of soaking treatment was longerthan the control. The chlorophyll content of the leave was promoted after the seed soakingwith azadirachtin. The contents of chlorophyll a, chlorophyll b and the total chlorophyllwere raised by 16.73%, 28.97% and 22.69% as compared to the control in the 6mg/Lazadirachtin solution. Based on the spraying treatment in 2.5 leaves, the growth of theaerial part was promoted while the subterranean part was inhibited. It was indicated thatthe weight of dry substance of the aerial part was significantly increased than the control.The weight of the aerial part dry substance in 1.5mg/L azadirachtin treatment wasincreased by 15.39% as compared to the contrast. The chlorophyll content of the leave inspraying treatment was raised. The contents of chlorophyll a, chlorophyll b and the totalchlorophyll were increased by 8.96%, 24.26% and 15.37% respectively after spraying withazadirachtin of 6mg/L. According to the single-plant experiment, it was clearly that theazadirachtin and neem oil improved the tillering ability of rice. The number of tillersreached 11.33 in the 6mg/L azadirachtin treatment and the control only reached 9.67. Atthe same time, the n更多还原