From Laboratory Screening to Greenhouse Flight Bioassay: Development of a Plant-Based Attractant for Tomicus brevipilosus

Tomicus brevipilosus Eggers is a major forest pest affecting Pinus yunnanensis Franch and Pinus kesiya var. Langbianensis (A.Chev.) Gaussen ex Bui in Southwest China. While attractants exist for related species, this study aimed to develop a more effective, tailored attractant for T. brevipilosus. We assessed the activity of host plant volatiles using electroantennography (EAG). Female and male beetles showed strong responses to different compounds: females to β-pinene, terpinolene, (+)-3-carene, and (R)-(+)-limonene; males to (+)-3-carene, 2-isopropyl-5-methylanisole, and D(+)-camphor. An optimized blend of these compounds achieved a high selection rate (57 ± 20%) in olfactory assays. This study represents a crucial preliminary investigation. The concentrations and release systems (rubber septa and centrifuge tubes) were optimized under controlled conditions to identify the most promising candidate for future scaling, rather than for immediate large-scale application. In semi-field cage bioassays, trap catch was highest at mid-canopy height (1.5 times branch-free height), under the cage canopy, and in treatments with low-to-moderate canopy density. This work provides a foundation for developing improved monitoring and management tools for T. brevipilosus.