Integrative Taxonomy, Seasonal Phenology, and Sex Pheromone Profiling of the Durian Seed Borer (Mudaria stahlgretschae) for Enhanced Pest Monitoring

The durian seed borer, Mudaria stahlgretschae, is a major economic pest that has significantly impacted durian cultivation in Southeast Asia; however, comprehensive biological and ecological data for this species remain limited. This study employs an integrative taxonomic approach, combining morphological examination with molecular validation of the mitochondrial cytochrome c oxidase subunit I (COI) gene. Phylogenetic analysis (Neighbor-Joining) confirmed that all collected specimens (n = 11) formed a distinct monophyletic clade within the genus Mudaria, showing a genetic identity of 95.75–96.85% with existing GenBank accessions, thereby confirming their identity as M. stahlgretschae. Systematic monitoring using light traps in Uttaradit Province revealed a clear seasonal phenology, with adult flight activity restricted to a five-month period from April to July 2025. Population density peaked in May (55.56%), synchronized with the mid-stages of durian fruit development. Furthermore, chemical profiling of female gland volatiles via GC-MS identified 40 compounds; among these, four putative sex pheromone candidates—1-Hexacosene, (Z)-7-Hexadecenal, 11-Octadecenal, and 2-Hexadecanol—were identified as key constituents based on their consistent detection across all replicates (n = 3), high relative abundance, and absence in male extracts or blank controls. These findings establish a critical foundation for developing synthetic pheromone lures and synchronized monitoring programs, offering a robust framework for the sustainable management of M. stahlgretschae in durian agroecosystems.