Bioactivity of Extracts from Sladenia celastrifolia against Larvae of Plutella xylostella

The bioactivities of the ethanol extracts from Sladenia celastrifolia on the larvae of diamondback moth,Plutella xylostella were investigated in laboratory by measuring antifeeding action of the extracts and larvae mortality after the larvae had fed on the extracts-coated cabbage leaves.The results indicated that leaf consumption by the insects was reduced,the larval mortality was increased and emergence rate of new adults was declined.The higher the concentration of the extracts was,the severer the effect on the pest was.The results showed that the medium antifeedant concentrations(AFC50) were 151.88 mg/L in 24 h,94.53 mg/L in 48 h for no-choice test.