Identification and field evaluation of sex pheromone for Erannis ankeraria Staudinger ( Lepidoptera: Geometridae )

BACKGROUND Erannis ankeraria (Staudinger) (Lepidoptera: Geometridae) is a defoliator of Larix , Quercus , and Picea trees. Recent outbreaks of this pest have caused extensive damage to the larch forests in north‐eastern China RESULTS Through gas chromatography‐electroantennographic detection ( GC ‐ EAD ) and gas chromatography–mass spectrometry ( GC – MS ), Z 3 Z 6 Z 9 ‐19:Hy, Z 3 Z 9 ‐ cis ‐6,7‐epo‐19:Hy, Z 6 Z 9 ‐ cis ‐3,4‐epo‐19:Hy, and Z 3 Z 6 ‐ cis ‐9,10‐epo‐19:Hy were identified from sex pheromone glands of Erannis ankeraria females. The quaternary mixture of these synthetic pheromone components at a ratio of 1:0.5:1.2:1.3 achieved the optimal trapping effect in field experiments. Biotransformation and activity assays revealed that Z 3 Z 6 Z 9 ‐19:Hy serves as a precursor of epoxynonadecadienes, regulates the upwind flight behavior of male moths, and exhibits a synergistic effect with the epoxy pheromone components. Notably, the 3,4‐ and 9,10‐epoxides, newly identified in the genus Erannis , both markedly decrease the captures of Colotois pennaria (Lepidoptera: Geometridae) CONCLUSIONS The sex pheromone of Erannis ankeraria was identified as a quaternary blend, which exhibits a remarkable efficacy in attracting Erannis ankeraria males, thereby offering a reliable tool for population monitoring. Z 3 Z 6 Z 9 ‐19:Hy acts as a precursor in the biosynthesis of three epoxynonadecadiene pheromone components, and is also a critical synergistic pheromone component. The 3,4‐ and 9,10‐epoxides likely mediate interspecific chemical communication between Erannis ankeraria and C. pennaria , enabling species‐specific recognition and reproductive isolation © 2025 Society of Chemical Industry.