Combinations of essential oils (EOs) are promising alternatives for pest management in storage grains. A high diversity of compounds in EOs and EO mixtures can increase their toxicity. Additionally, EOs can be useful in insecticide resistance programs. For this reason, we evaluated the fumigant toxicity and repellent effects of six essential oils (Dysphania ambrosioides, DA; Pelargonium graveolens, PE; Piper arboreum, PA; Piper diospyrifolium, PD; Piper gaudichaudianum, PG; and Piper tuberculatum, PT) separately and in binary combinations against adults of Sitophilus zeamais (the maize weevil). First, the insecticidal activity of all possible combinations of the six EOs were assessed. Next, the concentrations needed to cause 50% and 90% mortality (LC₅₀ and LC₉₀, respectively) in the S. zeamais population were determined for the most toxic EOs and mixtures. After that, the synergistic effect of the mixtures was also verified. Finally, the most toxic treatments were assessed to determine the time required to cause mortality of 50% of the population and check the repellent effects on S. zeamais. The binary mixtures of DA and PE, PT, PG, PD, and PA were the most toxic against S. zeamais. The LC₅₀ and LC₉₀ values for these treatments ranged between 1.77 and 2.25 μL L⁻¹ and from 2.42 to 7.64 μL L⁻¹, respectively. The mixtures were more toxic than the EOs tested separately, which indicates the occurrence of synergistic effects. All treatments caused mortality of 50% of the population of S. zeamais in less than 42 h of exposure. In addition, the combinations DA + PE, DA + PT, DA + PG, and DA + PA were repellent to S. zeamais. Based on these results, we conclude that the mixtures of EOs evaluated in this study are highly promising for the control of S. zeamais populations and can also be used for resistance management of this species.

精油(EO) 的组合是储存谷物害虫管理的有前途的替代品。EO 和 EO 混合物中化合物的高度多样性会增加它们的毒性。此外，EO 可用于杀虫剂抗性计划。出于这个原因，我们分别评估了六种精油（Dysphania ambrosioides , DA；天竺葵， PE ；Piper arboreum，PA；Piper diospyrifolium，PD；Piper gaudichaudianum，PG；和Piper tuberculatum， PT）的熏蒸毒性和驱避作用对Sitophilus zeamais成虫的二元组合（玉米象鼻虫）。首先，评估了六种 EO 的所有可能组合的杀虫活性。接下来，确定了在S. zeamais种群中导致 50% 和 90% 死亡率（分别为LC ₅₀和 LC ₉₀）所需的浓度，以用于毒性最强的 EO 和混合物。之后，还验证了混合物的协同作用。最后，对毒性最强的处理进行了评估，以确定导致 50% 人口死亡所需的时间，并检查对玉米链球菌的驱避效果。DA 和 PE、PT 、 PG、PD 和 PA的二元混合物对S 的毒性最大。玉米。LC ₅₀和 LC这些处理的_{90 个}值分别在 1.77 到 2.25 μL ^-1和 2.42 到 7.64 μL L ^{-1 之间}。混合物比单独测试的 EO 毒性更大，这表明发生了协同效应。所有处理都在暴露不到 42 小时的时间内导致 50% 的玉米白粉病种群死亡。此外，DA + PE、DA + PT、DA + PG 和 DA + PA 组合对S具有排斥性。玉米。基于这些结果，我们得出结论，本研究中评估的 EO 混合物非常有希望用于控制S. zeamais种群，也可用于该物种的抗性管理。