| Artemisia argyi Levl distributes abroad in China. It is an important natural source for biorational botanical insecticide and has excellent effects on insects, including killing insects directly, expelling insects and so on. In my thesis, the beet armyworm, Spodoptera exigua Hiibner was used as target insect. The main contents include the biological effects of different fractions on 5. exigua, the constituents from the fraction in ethyl acetate from A. argyi and the biological effects of some constituents on S. exigua. For the first time, we report two new terpene compounds, which have good effects on 5. exigua. These two new compounds may be used as the core structure for new insecticide exploitation.In the repellent experiments, the fractions in acetone and ethyl acetate had the best effects on the oviposition of S. exigua. The best effects happen at 2-3 d after copulation, which is the fastigium of the oviposition of the S. exigua. In the deterrent experiments, the fractions in acetone and ethyl acetate also had the best effects on the oviposition of S. exigua, with the average deterrent rate of two fractions greater than 50% at concentration of 10 mg/mL. Results indicate that these two fractions have excellent effects on the reduction of eggs from S. exigua. The results from the life table technique also confirm the conclusion.The toxicity of the crude extract to larva of 5. exigua was low, which indicates that A. argyi can't be used solely. However, the toxicity of the crude extract to larva was enhanced by addition of little amount of other insecticides or some synergists, which gives some hope for the application of A. argyi in the field.The constituents of the fractions in benzene, acetone and ethanol are identified by GC-MS technique. 12, 10 and 7 substances were identified in these three fractions, which have 6, 4 and 1 terpene compounds respectively. Two new terpene compounds are found: 2-Cyclohexen-1-ol, 1-methyl-4-(1 -methylethyl)-, trans, in the fraction in benzene and 2-Cyclohexen-1-ol, 2-methyl-5-(1-methylethenyl)-, trans, in the fraction in acetone. In the fraction in ethyl acetate, 20 substances are identified by GC-MS and GC-FTIR. In 20 substances, there are 9 terpene compounds, which have high contentsother than caryophyllene. Total content of 9 terpene compounds is 61.936%, which occupies 75.961% of the content of all identified substances. 3 terpene compounds are reported first, which are [2-Cyclohexen-1-ol, 1-methyl-4-(l -methylethyl )-, trans], [2-Cyclohexen-l-ol, 2-methyl-5-(1-methylethenyl)-, trans] and [Cyclohexene, l-methyl-4-(5-methyl-l-methylene-4- hexenyl)-, (S)-]. The contents of these three compounds are 1.284%, 7.031% and 10.056%. The high contents of the later two terpene compounds make conveniently for the preparation by HPLC.Camphor, borneol, eucalyptol, terpineol, caryophyllene, tetrahydrogeroniol and geranyl acetate are purchased from different chemical corporations. Two new terpene compounds, [2-Cyclohexen-1-ol, 2-methyl-5-(1-methylethenyl)-, trans] (No.4) and [Cyclohexene, 1-methyl-4-(5-methyl-1-methylene-4-hexenyl)-, (S)-] (No.9), are prepared by Preparative-HPLC. Antennal response, effects on development and reproduction of S. exigua by these 9 compounds are evaluated and a new method, Scintillant-bottle method, is developed for determining the deterrent effects of two new terpene compounds, whose amount is small. Results show that camphor and No.9 have the best effects on the development and reproduction of S. exigua, and No.4 also has good effects, close to or exceeding borneol. Further more, the mixtures of No.4 and No.9 and the mixture of camphor, bomeol, eucalyptol, No.4 and No.9 according to natural contents of them in GC separation also have good effects on S. exigua.In conclusion, the fraction in ethyl acetate has excellent effects on S. exigua and has most substances in GC-MS. So, this fraction is used as the material for the identification by GC-MS and GC-FTIR. In 20 substances identified in the fraction in ethyl acetate, there are 9 terpene com... |
PDF Full Text Request