Bioactivity of Methanol Extracts from Justicia procumbens L. of Chinese Medicine against Ostrinia furnacalis Guenee

In order to ascertain the bioactivity of methanol extracts from Justicia procumbens,their effects on contacting toxicity,antifeeding,stomach poisoning,inhibition of growth and oviposition deterrence of Ostrinia furnacalis Guenee were bioassayed in the greenhouse.The results showed that the extracts from J.procumbens L.had the bioactivity of certain contacting toxicity,strong antifeeding,stomach poisoning,growth inhibition and oviposition-deterrent activities against O.furnacalis.The mortality of the extracts at the concentration of 32 mg/mL against 3rd instar larvae of O.furnacalis within 24 and 48 h after treatment reached 28.33% and 43.33%,respectively.The choice and non-choice AFC50 values within 24 and 48 h after treatment in the anti-feeding test were 3.10,3.90 mg/mL and 4.44,5.77 mg/mL,respectively.The LC50 values of extracts against 3rd instar larvae of O.furnacalis within 6 and 7 d after treatment in the stomach poisoning test were 5.09 and 2.73 mg/mL,respectively.The extracts from J.procumbens also imposed great influence on the growth of O.furnacalis Guenee larvae.The treated larvae showed big reduction in body weight,weight gain and relative growth rate compared with the contro1.The IC50 values within 24 and 48 h after treatment were 0.84 and 0.53 mg/mL,respectively.The extracts from J.procumbens had strong oviposition deterrence against O.furnacalis adult,the AOC50 values within 24,48 and 72 h after treatment were 6.73,9.71 and 12.29 mg/mL,respectively.