| It's very important to find the latest biological pesticide propitious to pest control for the development of pollution-free agriculture. Plant-pesticide will replace chemical pesticide gradually owing to the advantages:varied modes of action; safe for higher animals and natural enemies;Pests are not easy to develop drug resistance; favorable to environment, etc. Cerbera Manghas is classified as an apocynaceous plant of Tanghinia distributing in Asia tropical regions, Australia and Madagascar; the whole plant is poisonous. It contains various compound ingredients such as flavone, lignanoid,iridoid and cardiac glycoside. Also, it has wide ranges of biological activity effective in anticancer, desinsection and bacteriostasis. The paper discourses on the extracts of toxic substance from a poisonous plant named Cerbera manghas as well as the test and research on the related biological activities. The main results are as below:1,Leaching the pulverized loft-dried Cerbera manghas leaves 3 times by ethanol and extracting it with the help of ultrasonic; getting the desired extract after decompressing and inspissating. After that, extracting by petroleum ether, ethyl-acetate and normal butanol orderly and finally isolating a compound from the crude extracts by the separation methods and technological means of column chromatography, thin-layer chromatography (TLC) and recrystal. Its structure was identified asβ-rhamn by modern Spectrum Techniques (infrared spectrometry,1H-NMR spectroscopy, Carbon NMR spectroscopy and mass spectroscopy). It's the first time the compound was found in the plant.2,Making compositional analysis to the volatile oils of Cerbera manghas leaves and fruits by coupling technique GC-MS for the first time and 13,15 compounds were identified separately. The chief ingredients of volatile oils of Cerbera manghas leaves were dibutyl hydroxy toluene (BHT), Propane-1,3-diol4-methyl-benzeneboronate and Phenol, etc; and the chief ingredients of volatile oils of Cerbera manghas fruits were trans-9-octadecenoic acid, Hexadecanoic acid, Octadecanoic acid and Phenanthrene, etc.3,Testing the biological activities of petroleum ether extract, ethyl acetate extract and normal butanol extract of Cerbera manghas leaves to plant pathogenic fungi and it's proved that 3 extracts had strong bacteriostatic activities against the orange Colletotrichum gloeosporioides. At concentration of 1.5mg/mL, the suppression ratio of normal butanol extract to the orange colletotrichum gloeosporioides was 92.24% and EC50 was 1.724mg/mL respectively.4,Toxicity test of petroleum ether extract, ethyl acetate extract and normal butanol extract of Cerbera manghas leaves to Spodoptera litura (Fabricius):it proved that ethyl acetate extract had the highest toxicity against Spodoptera litura(Fabricius). The related LC50 was 1.2773 mg/mL and the lethality rate was 90.00%. Testing the nonselective antifeedant activity and selective antifeedant activity of 3 extracts from cerbera manghas leaves, it showed that the extracts had different antifeedant activities on the trophic behaviour of the third instar larvae of Spodoptera litura (Fabricius). The antifeedant ratio of ethyl acetate extract to Spodoptera litura (Fabricius) was higher than that of petroleum ether extract and normal butanol extract. The order of the antifeedant ratios was:ethyl acetate extract> normal butanol extract> petroleum ether extract.5,Toxicity test of essential oils of Cerbera manghas leaves and fruits to Tribolium castaneum Herbst:the median lethal concentrations were 1.0067ml/L and 3.1189ml/L respectively; repellence test:the repellent ratio was over 70% at concentration of lml/L in 12-60h and leveled above repellency classⅣ.100% repellence of the essential oil of Cerbera manghas fruit was observed in 12h. Test on fumigation activities:After 24h,47h and 72h, the LC50 of the essential oils of Cerbera manghas leaves and fruits were respectively 2.0207, 1.7450,1.0160 ml/L and 1.1679,1.5171,1.8268ml/L。6,Toxicity test of the essential oils of Cerbera manghas leaves and fruits to Spodoptera litura (Fabricius):the median lethal concentration were 1.5545 ml/L and 1.1803 ml/L respectively; Test on the nonselective antifeedant activity:after 12h and 24h, the essential oils had definite antifeedant activities on the third instar larvae of Spodoptera litura (Fabricius) and the AFC50 were respectively 1.9240,1.3817ml/L and 1.5104,1.3372ml/L. Test on the selective antifeedant activity:after 12h and 24h, the AFC50 of the essentials oils to the third instar larvae of Spodoptera litura (Fabricius) were respectively 1.7783,2.0922ml/L and 1.9538,1.5027ml/L.The result of study showed that the extracts from Cerbera manghas had definite bacteriostatic and pesticidal activities. Therefore, further isolation and purification to the active ingredients will be of important research-value and use-value in application of the active ingredients to the plant-pesticide and bacteriostat.
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