Abstract: 【Aim】 This study aims to clarify the relationship between the boring rate and pupal weight of the oriental fruit moth, Grapholitha molesta, on host fruits and host species and fruit developmental stage, so as to provide the theoretical basis for its prediction and control. 【Methods】 The boring rates of the newly hatched larvae of G. molesta on fruits of six varieties of three fruit species ［Malus pumila (variety Gala apple), Amygdalus persica (varieties Dajiubao peach, Fengbai peach and Xiaguang nectarine), Pyrus bretschneideri (varieties Dangshan pear and Yuluxiang pear)］ at different developmental stages and on four fruit varieties (Dajiubao peach, Fengbai peach, Dangshan pear and Yuluxiang pear) with different fruit statuses at 72 h post inoculating eggs were determined in the laboratory. The boring rates of the newly hatched larvae on different apple varieties (Gala apple, Fuji apple and Golden delicious apple) at different 
developmental stages at 24 h and 72 h post inoculating eggs were compared. The pupal weight of G. molesta on Golden delicious apple, Fuji apple, Gala apple, Dangshan pear and Fengbai peach at different developmental stages were also determined. 【Results】 The boring rate of the newly hatched larvae of G. molesta at 72 h post inoculating eggs was the highest on Xiaguang nectarine, followed by on Gala apple, Dangshan pear, Yuluxiang pear, Dajiubao peach and Fengbai peach. Except Xiaguang nectarine, the developmental stage of the other five fruits significantly affected the boring rate of the newly hatched larvae. The boring rates of the newly hatched larvae at 72 h post inoculating eggs were 73.69% and 32.51% on young fruit and coloring fruit of Gala apple, respectively. The boring rates of the newly hatched larvae on Dajiubao peach, Fengbai peach, Dangshan pear and Yuluxiang pear at 72 h post inoculating eggs increased with the developmental stage of host fruits. The boring rates of the newly hatched larvae on the coloring fruits and mature fruits of three apple varieties significantly reduced with treatment time, but the boring rates on young fruits showed no significant change. Meanwhile, the host species and their developmental stage also affected the pupal weight of G. molesta, the female and male pupal weight of G. 
molesta on mature peach and pear were significantly higher than those on immature ones, and coloring apples are unsuitable to the female and male pupal weight of G. molesta. 【Conclusion】 Fruit species and developmental stage significantly affect the boring rate 
of the newly hatched larvae and the pupal weight of G. molesta, and the boring rate of the newly hatched larvae and the pupal weight of G. molesta on mature pear and peach are significantly higher than those on immature ones.

Key words: Grapholitha molesta; host plant, fruit variety, fruit developmental stage; boring rate, pupal weight