Contact and antifeeding effects on four species of the genus Datura against Mythimna separate and Pieris rapae

Contact and antifeeding effects on D.stramonium,D.tatula,D.innoxia and D.fastuosa against fifth instar larvae of M.separate and fourth instar larvae of P.rapae were researched.The results showed that the contact effect on the methanol extract from roots,stems and leaves of D.stramonium in initial bloom stage against fifth instar larvae of M.separate was the strongest,the next were the methanol extracts from flowers and roots,stems as well as leaves of D.tatula in initial bloom stage,the corrected mortalities were 23 %,19 % and 17 %,respectively.Among five different polar solvents(methanol,ethanol,acetone,petroleum ether and ethyl acetate)extracts from flowers and roots,stems and leaves of D.tatula as well as D.stramonium had the strongest contact activities against the larvae,the corrected mortalities were 20.83 %,17.93 % and 23 %,respectively.The methanol extract from flowers of D.tatula had the strongest contact activity against fourth instar larvae of P.rapae,the next was the methanol extract from flowers of D.stramonium,the corrected mortalities were 100 % and 80 %.There were no antifeeding effects on the methanol extracts from flowers and roots,stems and leaves of four species of stramonium in initial bloom stage against fourth instar larvae of M.separate.The antifeeding rates of the methanol extracts from flowers of D.stramonium and D.innoxia against the larvae of P.rapae were 95.54 % and 83.37 %.