Evaluation Of Insecticidal Activity Of Extracts From203Plants And Cephalotaxus Sinensis

It is an important foundation to get botanical insecticidal activity compounds to developbotanical pesticides. So far, the insecticidal activity of thousands of plants have beenevaluated, but the study is not yet enough. In this report we described the evaluated resultscovering203species of plants in China in order to find new insecticidal plants for developingbotanical pesticide.The main results are as follows:1. The population-inhibiting activity of acetone extracts from106plants were evaluatedagainst Sitophilus zeamais by diet-incorporation method. Forty-two plant extracts（0.013gDW/g） showed good population-inhibiting activity with more than50.0%of theinhibitory rate （64d）. Among them, Euonymus phellomanus, Quisqualis indica, Belamcamdachinenses and Scutellaria baicalensis showed the strongest inhibiting activity （100.0%inhibitory rate）.2. The antifeedant and toxic activity of water extracts（20mg/ml） from63Chineseherbal medicines and acetone extracts（1gDW/ml） from140plants were evaluated againstthe3rdlarva of Mythimna separata by leaf or insect-dipping method. The results showed thatthe water extractions have no obvious insecticidal activity,69of140acetone extracts showedantifeedant or toxic activity against the3rd larvae of Mythimna separata, and theantifeedant（24h） or mortality（72h） were higher than50.0%. Eighteen species with betterinsecticide activity were assayed further against3rdinstar larva of Plutella xylostella.Cephalotaxus sinensis, Paeonia suffruticosa, Glycyrrhiza uralensis and Acanthopanaxgracilistylus showed obvious insecticidal activity against the3rd larvae of M. separata and P.xylostella.3. The pesticidal spectrum of C. sinensis and A. gracilistylus were tested by using5insects. The results indicated that under tested dosage, A. gracilistylus was only toxic to the3rd larvae of Culex pipiens pallens and Mythimna separata，and Tetranychina hani，C.sinensis showed insecticidal acticities to all the tested insects, as follows：Sitophilus zeamais，Culex pipiens，Musca domestica，Myzus persicae and Tetranychina hani.The LC50（after48h） of A. gracilistylus against M. separata W. and P. xylostella L. were77.513,15.323mgDW·mL-1, and the C. sinensis were562.276,74.941mgDW·mL-1. TheAFC50（after48h） of A. gracilistylus against M. separata W. and P. xylostella L. were29.321，4.314mgDW·mL-1, and the C. sinensis were71.956，45.390mgDW·mL-1.The petrol ether extract of C. sinensis and the ethyl acetate extract of A. gracilistylus hadbetter antifeedant and toxic activity than the other solvent extractions from acetone extract.4. The essential oils were extracted from C. sinensis using hydrostillation and supercritical CO₂methods.The two essential oils（0.035ug/head） both showed strong contacttoxicity（100.0%and93.3%mortality separately） against the3rd larvae of M. separata.Although their chemical compounds and number are different by GC-MS, the maincompounds of the two essential oils both are phenolic and terpenoid compounds).5. The petrol ether extract of C. sinensis was preliminary separated by ColumnChromatographic．It was found that the weak polar fractions—Y5and Y6, with strong contacttoxicity against the3rd larvae of M. separata, the correct mortality（24h） was100.0%.In conclusion，C. sinensis, P. suffruticosa, G. uralensis, A. gracilistylus，E. phellomanus,Q. indica, B. chinenses and S. baicalensis are well worth looking into, and especially havefurther study on the compounds of C. sinensis.