In the present study, repellent activity of three plant essential oils (EOs) [anise (Pimpinella anisum L.), eucalyptus (Eucalyptus camaldulensis Dehn.) and peppermint (Mentha piperita L.)] and their major components (trans-anethole, 1,8-cineole and L-menthol, respectively) was evaluated at five concentrations (3.6, 7.1, 14.3, 28.6 and 57.1 µl/l air) through Y-tube olfactometer against the rice weevil, Sitophilus oryzae L. (Coleoptera: Curculionidae), under laboratory conditions. The binary (1:1) and ternary (1:1:1) combinations of the EOs and/or components were also evaluated for their possible combination effects (synergism, antagonism and additive effect). The results showed that all the EOs and components tested, both alone and in binary and ternary combinations, had a repellent activity on adult S. oryzae. However, repellency was concentration dependent (P = 0.05). None of the combinations tested had a statistically significant influence on the repellence against adult S. oryzae (P = 0.05). Based on the estimated RC₅₀ (the concentration required to obtain 50% repellency) values, binary and ternary combinations generally had lower RC₅₀ values, indicating that they were more repellent to S. oryzae than the single application of EOs or components, except for anise EO and 1,8-cineole. Considering the combination index (CI) values, most of the binary and ternary combinations showed synergistic effects (CI < 1), while some of them exhibited additive effects (CI = 1). However, no binary or ternary combination showed an antagonistic effect (C > 1). Overall results suggest that EOs and their components may help prevent the rice weevil infestations and can be used to develop new products that meet expectations.

在本研究中，三种植物精油（EOs）[茴香（Pimpinella anisum  L.），桉树（Eucalyptus camaldulensis Dehn。）和薄荷（Mentha piperita  L.）]的驱避活性及其主要成分（trans -anethole，1通过Y型管嗅觉计对稻象鼻虫（Sitophilus oryzae）的五个浓度（3.6、7.1、14.3、28.6和57.1 µl / l空气）分别评估了1,8-桉树脑和L-薄荷醇 L.（鞘翅目：Curculionidae），在实验室条件下。还评估了EO和/或组分的二元（1：1）和三元（1：1：1）组合的可能组合效果（协同作用，拮抗作用和累加作用）。结果表明，所有单独或以二元和三元组合形式测试的EO和组分均对成年米曲霉具有驱避活性。但是，排斥性是浓度依赖性的（P  = 0.05）。所测试的组合均未对成人稻米链霉菌的排斥性产生统计学上的显着影响 （P  = 0.05）。根据估算的RC ₅₀（获得50％排斥性所需的浓度）值，二元和三元组合通常具有较低的RC ₅₀值，这表明它们对米曲霉的排斥性 比单次施用EO或组分要高，除了茴香EO和1,8 -cineole。考虑到组合指数（CI）值，大多数二元和三元组合显示出协同效应（CI <1），而其中一些则表现出累加效应（CI = 1）。但是，没有二元或三元组合显示出拮抗作用（C> 1）。总体结果表明，EO及其成分可能有助于防止水稻象鼻虫侵扰，并可用于开发符合期望的新产品。