Green Synthesis, Formulation and Test Field of Lymantria monacha L. (Lepidoptera: Lymantriidae) Sex Pheromone in East European Region

The nun moth, <i>Lymantria monacha</i> L. (Linnaeus, 1758), is one of the most important defoliators of coniferous forests in Europe and Asia. In sexual communication, females produce three epoxides and an alkene: (-)-disparlure [(7<i>S</i>,8<i>R</i>)-<i>cis</i>-7,8-epoxy-2-methyloctadecane], (+)-monachalure [(7<i>R</i>,8<i>S</i>)-<i>cis</i>-7,8-epoxyoctadecane], (-)-monachalure [(7<i>S</i>,8<i>R</i>)-<i>cis</i>-7,8-epoxyoctadecane], and their corresponding olefins. This study aimed to develop a green synthesis pathway for all pheromonal components, emphasizing the use of common raw materials, a simplified three-step process, lower costs, and an environmentally friendly approach compared to existing methods. The proposed method introduces a novel synthetic route employing an innovative improvement alkylation step catalyzed by lithium iodide in diglyme. The synthesized compounds were characterized using GC-MS, ¹H NMR, and ¹³C NMR spectroscopy. Six synthetic blends were formulated for field testing, with the goal of identifying the most attractive composition. Field trials demonstrated that a blend with a 10:10:1 ratio of (±)-Disparlure, (±)-Monachalure, and (<i>Z</i>)-2-Methyl-7-octadecene exhibited the highest attraction efficiency.