Select Of Insecticidal Activity Of Eighteen Chinese Traditional Herbal Plants And Premliminary Study Of Bioactivity

In order to screen the environment friendly and highly effective insecticide of plant origin, this study was conduct to extract 52 kinds of extracts using cold soak method from 15 Branches 18 herbs, and then utilizing this crude extracts that respectively dissolved in water, ethanol and petroleum ether to bioassay the active against the third instar nymphs of Nilaparvata lugens (Stal) and third instar larvae of Spodoptera exigua (Hiibner) spray and stomach poisoning method. These results showed 18 kinds of Chinese traditiona herb plants that crude extracts from ethanol and petroleum ether had higher contact activity in comparation with S. teraexigua stomach poisoning. We futher assessed the contact activity against the third instar nymphs of Laodelphax striatellus (Fallen) using the spray method, and found six kinds of Chinese medicinal herb plants extracts of petroleum ether had relative higher activity against L.striatellus, then we further explored the active ingredient (Rf value) through the column chromatography analysis against petroleum ether ether crude extract of Lappula myosotis Moench. The detailed results were as follows:1.18 extracts of Chinese traditional herb plants had significantly contact effect to the brown planthopper, but the aqueous extracts generally had lower active than ethanol and petroleum ether bold. The corrected mortality on more than 50% except the aqueous extracts of Auklandia lappa and Stemona sessilifolia, the corrected mortality was 65.79% and 84.21%, respectively; the corrected mortality that more than 33% included Areca catectu, L.myosotis, Sophora flavescens, Gentian manshurica, Gardenia jasminoides, the others all lower 33%. Among the 18 kinds extracts of Chinese traditional herb plants, only A.lappa, Meliaazed arach, Omphalia lapidescens, Aloe vera and Gentiana manshurica extracts of alcohol had lower insecticidal activity than petroleum ether, the rest of the two kinds of the insecticidal activity of extracts is almost no difference. But it all had no significant stomach toxicity against the beet armyworm among these 18 kind extracts of Chinese traditional herb plants. The most corrected mortality was 33.33%,even some of them were 0. The results showed Stemonase ssilifolia Miql, Phellodendron amurenseSchneid, Torreya grandis Fort, Gardenia jasminoides Ellis, Lappula myosotis Moench, and Aucklandia lappa Decne ethanol or petroleum ether crude extracts had the highest insecticidal activity against the instar nymphs of the brown planthopper. S.ssilifolia, P.amurense, T.grandis, G.jasminoides, L. myosotis, and A. lappa petroleum ether crude extracts were more than 90%, most of them even could kill all the BPH third instar nymphs within 24h. Further analysis the most insecticidal activity of six extracts, the LC50 values was 0.0826g/mL,0.0455g/ml,0.0145g/mL,0.0047g/mL,0.0038g/mL,0.0033g/mL, respectively, the relative toxicity separately were 1.0,1.8,5.7,17.6,21.7 and 25.0.2. We bioassaied 18 kinds of Chinese traditional herbal plants ethanol and petroleum ether crude extract aginst the third instar nymphs of Laodelphax striatellus (Fallen) by the same spray method, the reults indicated these extracts also had better insecticidal activity against third instar nymphs small brown L.striatellus, where L.myosotis, T.grandis and G.jasminoides crude extract showed the highest activity, and ethanol and petroleum ether extract had correction death rate of 100% after 24 h dealed with, and the petroleum ether extract of the other Chinese medicine had slightly higher or significantly higher contact activity against small brown planthopper than the ethanol extracts, indicating that these herbs insecticidal active substances are mainly concentrated in the non-polar extracts. Further analysis the most insecticidal activity of six extracts, the LC50 values was 0.0856g/ mL,0.0456g/ml,0.0202g/mL,0.0045g/mL,0.0040g/mL,0.0036g/mL, respectively, the relative toxicity separately were 1.0,1.9,4.2,19.0,21.4 and 23.7.3. We explored the insecticidal activity of L. myosotis and A. lappa of petroleum ether crude extract that had not been reported as study object, and employed systems solvent extraction method to compare the two traditional Chinese medicine insecticidal activity. The results showed that the chloroform extract of the L.myosotis, and A. lappa had best activity against the brown planthopper, which also indicated the both Chinese medicine belonged to non-polar lipophilic, and activity detection for each flow stars on the extract L. myosotis column chromatography showed that the insecticidal active ingredient Rf value was 0.5556 to 0.5926 via activity tracing method anlysis.4. This study lays the foundation for purification and confirmation of new insecticidal compounds from plants, including developing their application prospect and detecting novel insecticidal lead compounds.