Uncommon C18 Conjugated Dienes Define the Sex Pheromone System of Thelosia camina (Lepidoptera: Apatelodidae), a Pest of Yerba Mate.

The yerba mate tree Ilex paraguariensis is widely consumed in South America, and the limited recommendation for pesticide use highlights the need for alternative pest-management strategies. Thelosia camina is an important defoliator whose damage severely reduces yields. This study investigated the sex-pheromone system of T. camina as a basis for pheromone-mediated control. Female pheromone glands were extracted and analyzed by gas chromatography-electroantennographic detection, revealing nine antennally active compounds. Structural elucidation identified three major components (13Z,15Z)-octadeca-13,15-dienal (4), (13Z,15Z)-octadeca-13,15-dien-1-ol (5) and (13Z,15Z)-octadeca-13,15-dien-1-yl acetate (9). Remaining components were stereoisomers and related monoenes consistent with the same double-bond system. All isomers were synthesized, field bioassays showed that both the ternary blend (4,5 and 9) and the acetate (9) alone attracted males at levels significantly higher than controls. These results confirm conjugated C18 dienes as key pheromone components of T. camina and provide a foundation for pheromone-based, sustainable management in yerba mate cultivation.