Abstract: 【Aim】 The overwintering site of the oriental fruit moth, Grapholita molesta (Busck) and the relationship between the number of overwintering larvae and adult occurrence were investigated in different orchards to provide the scientific basis for forecasting and controlling this insect pest. 【Methods】 Six typical orchards located in Jinan, Tai’an, Feicheng, Guangrao and Laiwu of Shandong Province were selected for systematic investigation and analysis. The method of scraping bark was used to investigate the survival rate of overwintering larvae of G. molesta and the overwintering locations on tree branches, and closed gauze was used to investigate the numbers of overwintering larvae in the soil. Meanwhile, the occurrence of overwintering adults was monitored by sex pheromone traps and the sugar and vinegar liquid, and the relationship between the numbers of overwintering larvae and adult occurrence was analyzed.【Results】 The survival rate of overwintering larvae of G. molesta was as high as 62.99%, and the numbers of overwintering larvae were significantly different among different orchards (P<0.001). More overwintering larvae were found in main trunk (28.48%) and bough (44.24%) located in lower (45.10%) and middle (46.28%) parts of fruit tree, while less overwintering larvae were found on the upper part of fruit tree (8.62%) and the lateral branches (27.28%). There were no significant differences in the number of overwintering larvae among four directions of tree branches (east: 27.57%; west: 26.13%; south: 23.76%; north: 22.54%). No significant correlation was found between the numbers of the overwintering larvae and overwintering generation adults caught in the same orchard. 【Conclusion】 G. molesta overwinters as mature larvae in main trunk and bough located in lower and middle parts of fruit tree or in the soil. In the same orchard, the population of overwintering larvae of G. molesta is not suitable to be the reference basis for the forecast and control of overwintering adults, because the surrounding environmental conditions also affect adult occurrence of this moth.

Key words: Grapholita molesta, overwintering larvae, overwintering site, adult occurrence, spatial distribution, orchard