Abstract:

Aimed to develop Cynanchum komarovii into low toxicity and high effective plant pesticide, Contacting toxicity, stomach poisoning, antifeeding and inhibiting growth and development of ethanol extract from Cynanchum komarovii against 3th instar larvae of Plutella xylostella were tested, and the insecticidal activities of ethanol extract, ethyl acetate extract and alkaloids were compared. The results showed that ethanol extract possessed obvious contacting(Lc50=4.3048 mg/mL), antifeeding and growth inhibition effects against 3th instar larvae, the stomach toxicity was weak. The activity of three samples were alkaloids(Lc50=2.9854 mg/mL)>ethanol extract(Lc50=4.3048 mg/mL)>ethyl acetate extract(Lc50=55.8676 mg/mL). The study suggested that the Cynanchum komarovii had significant biological activities on Plutella xylostella and the part of alkaloids were highest,so it has potential research and application values as plant pesticide.