Department of Medical Parasitology, Faculty of Medicine, AJA University of Medical Sciences, Tehran, Iran.
Department of Plant Protection, Faculty of Agricultural Sciences, University of Mohaghegh Ardabili, Ardabil, Iran.
Environ Entomol. 2021 Jun 18;50(3):692-698. doi: 10.1093/ee/nvab023.
Trogoderma granarium Everts, the Khapra beetle, is a major pest of stored products, especially grains. In this study, fumigant toxicity and sublethal effects of Eucalyptus camaldulensis Dehnh. (Myrtaceae) and Mentha piperita L. (Lamiaceae) essential oils (EOs) were investigated against different growth stages of T. granarium. To assess the sublethal effects, insects were exposed to an LC20 or LC50 concentration of each essential oil, and the ability of these oils to deter feeding, oviposition, and damage to wheat seeds and overall mass were surveyed. At LC50 concentrations, M. piperita EO showed higher fumigant toxicity than E. camaldulensis EO against eggs, 2nd instar larvae, 4th instar larvae, and adults of T. granarium. Furthermore, the adults were more sensitive to the tested EOs than immatures. In free-choice tests, both larvae and adults showed a preference for control-treated wheat seeds than for seeds treated with an LC20 or LC50 concentration of EOs from E. camaldulensis or M. piperita. In a no-choice test, adult females exposed to EOs showed lower fecundity and fertility in comparison to control females not exposed to EOs. Treatment of wheat seeds with E. camaldulensis or M. piperita EOs resulted in a dose-specific reduction in the number of damaged seeds and seed weight loss when compared to control. According to our results, both tested EOs, especially EOs extracted from M. piperita, showed good potential for use in integrated pest management strategies against T. granarium.
Everts 氏谷斑皮蠹，又名谷蠹，是一种严重危害储藏物的害虫，尤其对谷物危害极大。在本研究中，我们调查了桉树叶（桃金娘科）和薄荷（唇形科）精油对不同生长阶段的谷蠹的熏蒸毒性和亚致死效应。为了评估亚致死效应，我们将昆虫暴露于每种精油的 LC20 或 LC50 浓度下，并调查这些油对拒食、产卵和对小麦种子及总质量的损害的能力。在 LC50 浓度下，薄荷精油对谷蠹的卵、2 龄幼虫、4 龄幼虫和成虫的熏蒸毒性均高于桉树叶精油。此外，成虫比幼虫对测试的精油更为敏感。在选择试验中，幼虫和成虫均表现出对对照处理的小麦种子的偏好，而不是对桉树叶或薄荷精油 LC20 或 LC50 浓度处理的种子的偏好。在非选择试验中，与未暴露于精油的对照雌虫相比，暴露于精油的雌虫产卵量和繁殖力均降低。与对照相比，用桉树叶或薄荷精油处理小麦种子可导致受损种子数量和种子重量损失呈剂量依赖性降低。根据我们的研究结果，两种测试的精油，特别是从薄荷中提取的精油，在防治谷蠹的综合虫害管理策略中具有良好的应用潜力。
