Abstract: Lysosomal β-N-acetyl-D-hexosaminidase (EC 3.2.1.52) catalyzes the release of H-acetyl-D-hexosamine from glycoconjugates,playing important roles in insect growth and development.The OfHEX2 gene encoding a lysosomal β-N-acetyl-D-hexosaminidase was previously obtained from Ostrinia furnacalis.In order to understand whether OfHex2 could be a potential insecticide target,the physiological importance of OfHex2 was investigated by RNA interference.And two chemicals,2-acetamido-1,2-dideoxynojirimycin(2-ADN)and imidazole,were evaluated for their inhibitory activities toward OfHex2.The injection of ds OfHEX2 into the fifth instar larvae efficiently induced gene silencing of OfHEX2 at the larval stage but not at the pupal stage.RNA interference resulted in the transcription level dropping to 7.1% on the third day of the 5th instar larvae compared to the control,and caused abnormalities of larval abdomen,pupa and adult appendages.The mortality of abnormal pupae was around 15%.These results showed that OfHex2 deficiency in Ostrinia furnacalis led to the aberrant and indirect lethal phenotypes,suggesting that OfHex2 was physiologically important and might be a potential target for insecticide designing.The results of inhibition experiment showed that 2-ADN competitively inhibited the activity of OfHex2 with a Ki value of 0.94±0.035 μmol/L.