| Based on studying biological activities of diffrent polar solvent extractives of Eucalyptus leaves of the Eucalyptus citriodora,E. Globulus,E. grandis×E. urophylla,E. dunnii,G9 and 184, the E. grandis×E. urophylla extractive, the insecticidal activitive of which was stronger in six Eucalyptus, was extracted, isolated and identified, and was studied on the activitives of mainly insecticidal component. The results showed that as follow:1,The 95% ethanol ultrasonic assisted extraction process from Eucalyptus leaves was conducted, adopted three factors and three level orthogonal design. The best extraction condition were ultrasonic frequency 40KHz, extraction time 40 min, ratio of solid to liquid 1:25.2,The active components in eucalyptus leaves were extracted by using ultrasonic assistant extraction and soxhlet extraction methods and some organic solvents, such as 95% ethanol, chloroform and ethyl acetate. The antifeedant activities determination to the 3rd-instar larvae of Plutella xylostella showed that 95% ethanol solvent extractives used ultrasonic wave assisting extracting method had the highest antifeedant activity. The Antifeedant rate of the E. grandis×E. urophylla against the 3rd-instar larvae of P. xylostella was highest and reached to respectively 84.07% and 78.62%, in 24h,48h, at the treatment concentration of 15mg/ml.3,The biological activities of 95% ethanol and ultrasonic assisted extracts of the six kinds of eucalyptus leaves were determined.①Different eucalyptus leave extraction has the certain stomach toxicity to the 2nd-instar larvae of the P. xylostella. When dealing with concentration of 20mg/ml, for 5 days, the corrective mortality rate of E. citriodora extractive reached to 70%, and the stomach toxicity of it was the strongest in six Eucalyptus leaves extractives.②Different eucalyptus leave extractives to the P. xylostella showed oviposition repellent effect. The oviposition repellent effect of E. grandis×E. urophylla was the strongest. At the 10mg/ml concentration, the selective oviposition repellent rate was 63.67%, IIPC was 0.2222, the non-selective oviposition repellent rate was 80.34%,ⅡPC was 0.1967.③Different eucalyptus leave extractives had stronger repellence and fumigation activities against Sitophilus oryzae and Tribolium castaneum adults. The repellent effect of E. grandis×E. urophylla extractive on T. castaneurn and S. oryzae was excellent and repellent rates respectively were 87.37%,80.26%, repellent grade was V level, while treated with 10mg/cm2 concentration for 24h. The Egrandis×E. urophylla had the fumigation effect on S. oryzae and T. castaneurn whose the correceted mortalities were respectively 85.05%,48.88%, while treated with 32mg/L concetration for 72h.4,The active substances of the 95% ethanol extracts of E. grandis×E. urophylla were isolated with the liquid-liquid extraction method. The main active ingredients were in petroleum ether extract layer of the E. grandis×E. urophylla. The petroleum ether extractive had the antifeedant effect on the 3rd-instar larvae of P. xylostella, and the antifeeding rate was 82.05%. The non-selective oviposition repellent rate against the P. xylostella adults was 63.67%, while treated with 1 Omg/ml concentration for 24h. The petroleum ether extractive had the repellent effect on T. castaneurn adults, and the repellent rate was 88.18%, repellent grade was V level, while treated with 1 Omg/cm2 concentration for 72h.5,The active ingredients of the petroleum ether extract layer of E. grandis×E. urophylla were separated with silica gel column chromatography. The L-2 component had the most bioactive. The L-2 component had the antifeedant effect on the 3rd-instar larvae of P. xylostella, and the antifeeding rate was respectively 84.69% and 76.07%, AFC50 was 1.96mg/ml, while treated with 10mg/ml concentration for 24h and 48h. The L-2 had the repellent effect on T. Castaneum adults, and the repellent rate was 81.29%, repellent grade was V level, while treated with 10mg/cm2 concentration for 72h.6,The chemical components of E. grandis×E. urophylla petroleum extract and L-2 was mainly made up of 1,8-cineole, by identified by gas chromatography-mass spectrometry (GC-MS) method. |
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