In the present work, we evaluate the toxic and repellent properties of lemongrass (Cymbopogon citratus (DC. ex Nees) Stapf.) essential oil and its components against Sitophilus granarius Linnaeus as an alternative to insecticide use. The lethal dose (LD₅₀ and LD₉₀), survivorship, respiration rate, and repellency on adults of S. granarius exposed to different doses of lemongrass oil and some of its components were evaluated. The chemical composition of the essential oil was found to have the major components of neral (24.6%), citral (18.7%), geranyl acetate (12.4%), geranial (12.3%), and limonene (7.55%). Lemongrass essential oil (LD₅₀ = 4.03 µg insect^–1), citral (LD₅₀ = 6.92 µg insect^–1), and geranyl acetate (LD₅₀ = 3.93 µg insect^–1) were toxic to S. granarius adults. Survivorship was 99.9% in insects not exposed to lemongrass essential oil, decreasing to 57.6%, 43.1%, and 25.9% in insects exposed to LD₅₀ of essential oil, citral, and geranyl acetate, respectively. The insects had low respiratory rates and locomotion after exposure to the essential oil, geranyl acetate, and citral. Our data show that lemongrass essential oils and their components have insecticidal and repellent activity against S. granarius and, therefore, have the potential for application in stored grain pest management schemes.

中文翻译：

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柠檬草精油及其成分对谷粒象甲的急性毒性和亚致死作用。


在目前的工作中，我们评估了柠檬草（ Cymbopogon citratus (DC. ex Nees) Stapf.）精油及其成分作为杀虫剂替代品对Sitophilus granarius Linnaeus 的毒性和驱避特性。对接触不同剂量柠檬草油及其某些成分的香茅成虫的致死剂量（LD ₅₀和LD ₉₀ ）、存活率、呼吸率和驱避性进行了评估。精油的化学成分主要成分为橙花醛（24.6%）、柠檬醛（18.7%）、乙酸香叶酯（12.4%）、香叶醛（12.3%）、柠檬烯（7.55%）。柠檬草精油（LD ₅₀ = 4.03 µg 昆虫^–1 ）、柠檬醛（LD ₅₀ = 6.92 µg 昆虫^–1 ）和乙酸香叶酯（LD ₅₀ = 3.93 µg 昆虫^–1 ）对S. granaius成虫有毒。未接触柠檬草精油的昆虫的存活率为 99.9%，接触精油、柠檬醛和乙酸香叶酯的 LD ₅₀的昆虫的存活率分别下降至 57.6%、43.1% 和 25.9%。接触精油、乙酸香叶酯和柠檬醛后，昆虫的呼吸频率和运动能力都较低。我们的数据表明，柠檬草精油及其成分对谷粒夜蛾具有杀虫和驱避活性，因此具有在储粮害虫防治计划中应用的潜力。