Abstract: 【Aim】 This study aims to investigate the effects of humidity on the survival rate and boring rate of the oriental fruit moth Grapholitha molesta (Busck), and the critical stage of humidity affecting its final survival rate. 【Methods】 At five relative humidity (25%, 40%, 55%, 70% and 85%) indoor, the number of eggs laid per female, egg hatching rate, larval boring rate, pupation rate, pupal eclosion rate and the time of oviposition, pupation and eclosion of G. molesta were recorded and analyzed.【Results】 Humidity had no effect on pupation rate of G. molesta, which stayed 100% at all the five relative humidity. Humidity had a significant influence on the number of eggs laid per female, egg hatching rate, larval boring rate, pupal eclosion rate and generation survival rate, all of which increased with the humidity. The most critical life stage that the humidity had a significant influence on the survival rate was the larval boring stage, followed by adult, egg, pupal and the last instar larval stages. Humidity had significant influences on the generation survival rate in the egg hatching stage, adult stage and larval boring stage. Meanwhile, higher humidity was beneficial for oviposition, pupation and eclosion of this insect, while the development was delayed under drier conditions. 【Conclusion】 Humidity has significant effects on the survival rate, larval boring rate and fecundity of G. molesta. Adult, egg and larval boring stages of G. molesta are the critical stages when its population and boring rate are impacted by humidity.

Key words: Grapholitha molesta, humidity, survival, fecundity, boring rate