The essential oils (EOs) are volatile plant extracts that are commonly considered as potential biopesticides. They present promising properties as relatively safe and potent insecticides, primarily delivered via fumigation. Such specificity of the EOs has led to the growing interest of researchers and, subsequently, to an increasing body of publications. The studies focusing on assessing the insecticidal action of EOs frequently require testing the effects of several dilutions of a given EO. To this end, researchers employ a range of solvents differing widely between the studies. While informative, the standardization concerning either tested oil or pest species is lacking in these studies. The presented study herein aimed to test whether the solvent used could affect the observed insecticidal activity of tested EO. As the model setup for studying the possible influence of solvents on the insecticidal effect of EOs, two EOs: mint and rosemary were chosen. The EOs were applied in fumigation assay against three economically important species of stored product pests: Callosobruchus maculatus, Sitophilus oryzae, and Tribolium castaneum. Each EO was tested in three concentrations—diluted with a range of solvents; dimethyl sulfoxide, acetone, methanol, ethanol, paraffin (mineral) oil, ultrapure water with 0.1% polysorbate 20 (TWEEN^® 20). The results confirm the hypothesis that the applied solvent could significantly alter the observed efficiency of tested EO. Such a result is of crucial value for conducting credible meta-analysis as well as for establishing a high standard of reproducibility.

中文翻译：

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稀释介质在精油熏蒸杀虫活性研究中的作用

香精油（EOs）是挥发性植物提取物，通常被认为是潜在的生物农药。它们作为主要通过熏蒸提供的相对安全和有效的杀虫剂，展现出令人鼓舞的特性。EO的这种特殊性导致研究人员的兴趣日益增长，随后，出版物也越来越多。专注于评估EO的杀虫作用的研究经常需要测试给定EO的几种稀释液的作用。为此，研究人员使用了一系列在研究之间差异很大的溶剂。尽管提供了信息，但这些研究缺乏有关受试油或害虫种类的标准化。本文提出的研究旨在测试所用溶剂是否会影响所测EO的杀虫活性。作为研究溶剂可能对EO杀虫效果影响的模型设置，选择了两种EO：薄荷和迷迭香。EOs用于熏蒸测定中，针对三种经济上重要的储藏产品有害生物：纹豆象，米象和赤拟谷盗。每个EO均以三种浓度进行了测试-用一系列溶剂稀释；二甲亚砜，丙酮，甲醇，乙醇，石蜡（矿物）油，超纯水，含0.1％聚山梨醇酯20（TWEEN ^® 20）。结果证实了这样的假设，即所施加的溶剂可以显着改变所观察到的EO的效率。这样的结果对于进行可靠的荟萃分析以及建立高可重复性标准具有至关重要的价值。