Efficacy of essential oil from Mosla chinensis Maxim. cv. Jiangxiangru and its three main components against insect pests

Abstract

Mosla chinensis Maxim. cv. Jiangxiangru (MCJ) is a traditional Chinese herb, which can be obtained in large quantities by artificial cultivation. In order to understand industrial value of MCJ resources, the essential oil (EO) of MCJ was obtained by steam distillation, analyzed by gas chromatography-mass spectrometry (GC-MS), and evaluated by bioassay and greenhouse trials against Mythimna separate, Myzus persicae, Sitophilus zeamais, Musca domestica and Tetranychus cinnabarinus. The GC-MS results showed that the main components in MCJ EO were thymol (50.60 %), β-thymol (22.32 %) and carvacrol (18.44 %), accounting together for more than 90 % of all compositions. MCJ EO and its three main components showed high fumigant activity against five species insect pests, in the descending order (LC50, μL/L air): T. cinnabarinus adults (3.83), M. persicae adults (4.34), M. separate 3rd instar larvae (4.49), M. domestica adults (5.66), and S. zeamais adults (53.71). Moreover, thymol exhibited higher fumigation toxicity than β-thymol and carvacrol, with the LD50 values of 1.66–59.20 μL/L air to five species insect pests. Greenhouse experiments indicated that MCJ EO 10 % emulsion exhibited obvious corrected control efficacy of about 87.92 % and 77.34 % against M. persicae and T. cinnabarinus on kidney bean (Phaseolus vulgaris) plants after 7 days treatment at 300 ghm−2, respectively. As a traditional Chinese medicinal herb with a large-scale planting area, MCJ provides low-cost, abundant raw materials for production of MCJ EO. And MCJ EO, a safe and broad-spectrum insecticidal active ingredient, has the potential to be developed as novel botanical pesticides for the management of agricultural, sanitary and stored pests.