Morphological and Molecular Characterization of Grapholita molesta (Lepidoptera: Tortricidae) and Its Distribution in Stone Fruit Orchards

Abstract

The oriental fruit moth, Grapholita molesta (Lepidoptera: Tortricidae), is a destructive pest of stone fruit orchards, causing significant losses through larval feeding in shoots and fruits. The present study focuses on morphological and molecular characterization of G. molesta and its distribution across major stone fruit-growing regions. Field surveys were conducted in peach, plum, and nectarine orchards, and infested shoots and fruits showing characteristic tunneling damage were collected for analysis. Adult moths and larvae were examined based on key morphological traits, including wing pattern, genitalia structure, and larval head capsule features, confirming species identity. Molecular identification was performed using mitochondrial COI gene sequencing, which validated morphological diagnosis and revealed genetic similarity among populations from different locations. Phylogenetic analysis indicated low to moderate genetic variation, suggesting recent population expansion and dispersal across orchards. Distribution studies showed that G. molesta was widely present across all surveyed orchards, with higher infestation levels in unmanaged or poorly managed fields. Seasonal monitoring revealed peak population activity during warm months, coinciding with active fruiting stages of host plants. Environmental factors such as temperature and host availability strongly influenced pest abundance and spread. The study highlights the integration of morphological and molecular tools for accurate identification and monitoring of G. molesta. Overall, the findings provide important insights into the genetic identity, population structure, and spatial distribution of this pest in stone fruit ecosystems. These results support the development of targeted monitoring and integrated pest management strategies aimed at reducing damage caused by G. molesta in commercial orchards.