Insecticidal Activity of Extract from Cynanchi Auriculati against Agricultural Pests

In order to examine the insecticidal activity of Cynanchi Auriculati, dropping method was used for the testing of the activiyies of ethanol extract against the five kinds of pests (Plutella xylostella, Mythimna separata, Pieris rapae, Aphis and Homona coffearia) The results showed that 95% ethanol extract of Cynanchi Auriculati exhibited strong impact on Plutella xylostella, Aphis and Homona coffearia, but weak effect on Pieris rapae and almost no activity on Mythimna separata. The corrected mortality against five species of pests under the concentration of 50.0mg/mL were in the order of Aphis (97.70%) > Homona coffearia (88.91%) > Plutella xylostella (83.33%) > Pieris rapae (30.00%) after 48 h. Five different polar extracts were also investigated of the activities against Plutella xylostella,the mortalities on 3th larvae of Plutella xylostella were in the order of petroleum ether (97.95%) > chloroform (42.17%) > ethyl acetate (28.57%) > distilled water (18.37%) > n-Butanol (11.53%).