Study On Insecticidal Activity Of Angelica Sinensis Extract And Its Synergistic Effect With Ricinus Communis Extract And The Preparation Of The Mixture

The mixture of plant extracts their joint insecticidal effect is the hotspot in current research region of botanical pesticides.Angelica sinensis is a traditional Chinese medicine, with a variety of pharmacological activities. According to the literature, Angelica sinensis has insecticidal activity to some pests, and shows synergies with some plant extracts. Ricinus communis, which is rich in resources in our country, is a good insecticide plant for its ingredients ricinine, But the insecticidal activity of crude extracts is limited.Insecticidal activities of Ricinus communis and Angelica sinensis extract and their mixture were systematically studied. The toxic action of extracts from Angelica sinensis by different solvents against larvae of S.exigua and Myzus persica was investigated. The results showed that the extract by ethanol had the highest activity. The ethanol extract was then extracted by three solvents for three fractions. The ethyl acetate fraction was higher toxic than the others. And lactone compounds among the extract was deduced as the main insecticidal substances according to the qualitative analysis. The mode of insecticidal action of ethanol extract from Angelica sinensis was combination of stomach toxic activity and antifeedant activity. The response surface analysis was used to optimize the alcohol extraction process, and the optimal condition was determined as:extraction time3.5h, extraction temperature85℃and solid-liquid ratio1:27. The toxic action of Ricinus communis extract by water and ethanol against larvae of S.exigua was tested. The ethanol extract showed superior insecticidal activity compared with the water extract. And its insecticidal mode was combined action of contacting activity and stomach toxic activity. Based on the above work, the combined effect of mixture with Ricinus communis extract and Angelica sinensis extract in different ratio was detected. The synergistic action of mixture of2.55:1was notable. The mode of insecticidal action of mixture was the combined action of contacting activity, stomach toxic activity and antifeedant activity. The emulsifiable formulation of mixture was studied. After the determination of the type and content of solvent, emulsifier and synergist, the formation was obtained as follows:mixture25%, emulsifier15%, synergist1%and the rest was solvent.