Acaricidal activity of the aggregation pheromone of Japanese pine sawyer against two-spotted spider mite

Abstract

Japanese pine sawyer (Monochamus alternatus) (Coleoptera: Cerambycidae), a vector of pine wilt disease, produces male-produced aggregation pheromone called monochamol, 2-(1-undecyloxy)-1-ethanol (C11OEtOH). After the identification of unique nematicidal activity of the synthetic monochamol and its homologues (ROEtOH: R = C-7-C-11) against Bursaphelenchus xylophilus nematode, their acaricidal activities were evaluated against two spotted spider mite (TSSM, Tetranychus urticae Koch) (Acari: Tetranychidae). In a leaf disc bioassay method, 100 mgL(-1) of monochamol and 2-(1-decyloxy)-1-ethanol (C10OEtOH) exhibited 100% adult mortality and zero fecundity. Along with C11OEtOH and C10OEtOH, 2-(1-octyloxy)-1-ethanol (C8OEtOH) and 2-(1-nonyloxy)-1-ethanol (C9OEtOH) were also 100% acaricidal with complete oviposition inhibition at increased concentration of 1000 mgL(-1). When the TSSM eggs on leaf discs were immersed in 1000 mgL(-1) solutions, none of the components were ovicidal. Egg hatching was completely inhibited by three components (C9OEtOH, C10OEtOH and C11OEtOH) at 6000 mgL(-1) and by four components (C8OEtOH, C9OEtOH, C10OEtOH and C11OEtOH) at 8000 mgL(-1). However, none of the compounds showed acaricidal effects in 0.5 h and 24 h residual toxicity tests at 1000 mgL(-1). This study highlights the potential acaricidal activity of monochamol and its homologues. Notably, the monochamol and its C-10-homologue could be listed as efficient acaricidal agents.