Insecticidal Activity against Myzus persicae of Terpinyl Acetate and Bornyl Acetate in Thuja occidentalis Essential Oil

Essential oils have insecticidal activity against several insects and are composed of numerous compounds. This study investigated the insecticidal effects of the Thuja occidentalis L. (Cupressaceae) essential oil, terpinyl acetate, and bornyl acetate against the peach aphid [Myzus persicae (Sulzer)]. The insecticidal effect of essential oils on three Cupressaceae plants was highest in T. occidentalis. The Thuja occidentalis essential oil was extracted by steam distillation, and the optimum conditions were found. The GC-MS profiling of essential oil components extracted from T. occidentalis leaves identified 16 volatile compounds. The main components were alpha-thujone (16.58%), beta-myrcene (14.62%), bornyl acetate (9.31%), and terpinyl acetate (8.52%). As a result of the metabolite profiling of three Cupressaceae plants, terpinyl acetate and bornyl acetate were present in large amounts in all of the essential oils, and they had an acetate structure, so it was estimated that they had insecticidal activity. The insecticidal activity of these two compounds was stronger than the other individual monoterpene compounds. The addition of surfactants to the terpinyl acetate and bornyl acetate showed strong insecticidal activity. Terpinyl acetate and bornyl acetate can be used as environmentally friendly insecticidal-active compounds.