Abstract

Essential oils (EOs) represent valuable alternatives in handling pest insects in stored grains. The main objective of this study was to evaluate the chemical composition as well as the repellent, fumigant, and oviposition inhibition activities of the rosemary (Rosmarinus officinalis) and citronella (Cymbopogon nardus) EOs against Ulomoides dermestoides. Ethyl 3-[acetyl(butyl)amino] propanoate (IR3535), an active ingredient in repellent formulations was used as a positive control. The chemical compositions of the EOs were characterized by GC/MS. The EOs major compounds (>10 %) included 1,8-cineole (24.6 %), α-pinene (17.7 %), camphor (12.4 %), and camphene (11.3 %) for rosemary, whereas for citronella, the most abundant components were citronellal (25.3 %), citronellol (17.9 %) and geraniol (11.6 %). The biological action observed was dependent on the concentration used. Both EOs showed 100 %-repellency at the highest tested concentration (16 μL/mL) with RC₅₀ values lower than 2.6 μL/mL after 4 h-exposure. Contact toxicity results showed that all treatments had mortality rates lower than 40 %, while fumigant action did not exceed 25 %. The exposure of adult insects to sublethal concentrations of the two EOs significantly inhibited oviposition at 2 and 4 μL/mL. These data suggest that citronella and rosemary EOs, employing different toxicity mechanisms, could be useful candidates for formulations utilized in the management and pest control in stored products.

摘要

精油 (EO) 是处理储存谷物中害虫的宝贵替代品。本研究的主要目的是评估迷迭香 ( Rosmarinus officinalis ) 和香茅 ( Cymbopogon nardus ) EOs对Ulomoides dermestoides的化学成分以及驱避剂、熏蒸剂和产卵抑制活性。. 3-[乙酰（丁基）氨基]丙酸乙酯（IR3535）是驱虫剂配方中的一种活性成分，用作阳性对照。EO 的化学成分通过 GC/MS 进行表征。EOs 的主要化合物 (>10%) 包括 1,8-桉树脑 (24.6%)、α-蒎烯 (17.7%)、樟脑 (12.4%) 和莰烯 (11.3%) 的迷迭香，而对于香茅，最丰富的成分为香茅醛 (25.3 %)、香茅醇 (17.9 %) 和香叶醇 (11.6 %)。观察到的生物作用取决于所使用的浓度。两种 EO 在最高测试浓度 (16 μL/mL) 和 RC _{50 下}均显示出 100% 排斥性暴露 4 小时后值低于 2.6 μL/mL。接触毒性结果表明，所有处理的死亡率均低于 40%，而熏蒸作用不超过 25%。将成虫暴露于亚致死浓度的两种 EO 中，在 2 μL/mL 和 4 μL/mL 时显着抑制了产卵。这些数据表明，采用不同毒性机制的香茅和迷迭香 EO 可能是用于储存产品中管理和害虫控制的制剂的有用候选者。