[Objective]The aim was to screen out plants which had strong contact activity against Lipaphis erysimi Kaltenbach. [Method]Twenty plant species which were collected from Gupo Mountain in Hezhou of China were extracted with methanol by cold soaking method. Contact activities of 20 methanol plant extracts against L. erysimi were determined by capillary micro spot method. [Result]The methanol extracts from Mussaenda esquirolli Levl. and Folium trematis Orientalis had the highest contact activities against L. erysimi at the dose of 10 μg / head,and their 24 h corrected mortality rates were 92. 22% and 92. 15% ,respectively; followed by Folium trematis and Viola hossei,with 24 h corrected mortality rate of 87. 59% and 82. 95% ,respectively. The methanol extract of Hedyotis lancea had medium activity,with 24 h corrected mortality rate of 65. 52% . Methanol extracts of the other plants had low contact activities against L. erysimi,with the corrected mortality rate lower than 50% . The methanol extracts of M. esquirolli,F. variolosa and F. trematis had high contact toxicity,with LD50 of 0. 768 6,0. 784 1 and 1. 504 4 μg / head,respectively. [Conclusion] M. esquirolli,F. variolosa and F. trematis show exploitation potential,and they are worth further studying.
