Insecticidal activities and action mechanism on extracts from castor flowers against Mythimna separate

Insecticidal activities and action ways on extracts from castor flowers against Mythimna separate were investigated.The results showed that contact effect on the extract of ethanol against the fifth instar larvae was the strongest,the correct mortality was 16.9 %.Antifeeding effect on the extract of ethyl acetate against the larvae was the strongest,the antifeeding rate was 41.5 %.Stomach poisoning effect on the extract of ethyl acetate against the larvae was the strongest,the next was the extract of petroleum ether,the mortalities were 42.5 % and 41.5 %,respectively.The extract of petroleum ether had the strongest development inhibition effect against the larvae,the inhibition rates were 66.88 %,66.98 %,59.39 %,55.63 % and 38.66 % after 3,4,5,6,7 days.Among different solvents from the extract of ethanol,the fraction of petroleum ether had the strongest contact effect against the larvae,and the correct mortality was 53.1%.The fraction of petroleum ether had some extent inhibition effect on Na+-k+-ATPase.