Pyrethroid resistance is a significant threat to agricultural, urban and public health pest control activities. Because economic incentives for the production of novel active ingredients for the control of public health pests are lacking, this field is particularly affected by the potential failure of pyrethroid-based insecticides brought about by increasing pyrethroid resistance. As a result, innovative approaches are desperately needed to overcome insecticide resistance, particularly in mosquitoes that transmit deadly and debilitating pathogens. Numerous studies have demonstrated the potential of plant essential oils to enhance the efficacy of pyrethroids. The toxicity of pyrethroids combined with plant oils is significantly greater than the baseline toxicity of either oils or pyrethroids applied alone, which suggests there are synergistic interactions between components of these mixtures. The present study examined the potential of eight plant essential oils applied in one of two concentrations (1% and 5%) to enhance the toxicity of various pyrethroids (permethrin, natural pyrethrins, deltamethrin and β-cyfluthrin). The various plant essential oils enhanced the pyrethroids to differing degrees. The levels of enhancement provided by combinations of plant essential oils and pyrethroids in comparison with pyrethroids alone were calculated and synergistic outcomes characterized. Numerous plant essential oils significantly synergized a variety of pyrethroids; type I pyrethroids were synergized to a greater degree than type II pyrethroids. Eight plant essential oils significantly enhanced 24-h mortality rates provided by permethrin and six plant essential oils enhanced 24-h mortality rates obtained with natural pyrethrins. By contrast, only three plant essential plants significantly enhanced the toxicity of deltamethrin and β-cyfluthrin. Of the plant essential oils that enhanced the toxicity of these pyrethroids, some produced varying levels of synergism and antagonism. Geranium, patchouli and Texas cedarwood oils produced the highest levels of synergism, displaying co-toxicity factors of > 100 in some combinations. To assess the levels of enhancement and synergism of other classes of insecticide, malathion was also applied in combination with the plant oils. Significant antagonism was provided by a majority of the plant essential oils applied in combination with this insecticide, which suggests that plant essential oils may act to inhibit the oxidative activation processes within exposed adult mosquitoes.

中文翻译：

---

植物精油可协同各种拟除虫菊酯类杀虫剂并拮抗埃及伊蚊的马拉硫磷。

拟除虫菊酯抗性是对农业，城市和公共卫生害虫防治活动的重大威胁。由于缺乏生产用于控制公共卫生害虫的新型活性成分的经济诱因，因此该领域特别受到因拟除虫菊酯抗性增强而导致的拟除虫菊酯类杀虫剂的潜在失败的影响。结果，迫切需要创新的方法来克服对杀虫剂的抗性，特别是在传播致命和致弱性病原体的蚊子中。大量研究表明，植物精油具有增强拟除虫菊酯功效的潜力。拟除虫菊酯与植物油组合的毒性明显大于单独使用的油或拟除虫菊酯的基线毒性，这表明这些混合物的成分之间存在协同相互作用。本研究检查了以两种浓度（1％和5％）之一使用的八种植物精油增强各种拟除虫菊酯（氯菊酯，天然除虫菊酯，溴氰菊酯和β-氟氰菊酯）的毒性的潜力。各种植物精油在不同程度上增强了拟除虫菊酯的含量。计算了与单独的拟除虫菊酯相比，植物精油和拟除虫菊酯的组合所提供的增强水平，并表征了协同效果。许多植物精油可显着增效各种拟除虫菊酯。与II型拟除虫菊酯相比，I型拟除虫菊酯具有更大的协同作用。八种植物精油显着提高了苄氯菊酯提供的24小时死亡率，六种植物精油提高了天然除虫菊酯获得的24小时死亡率。相反，仅三株植物必需植物显着增强了溴氰菊酯和β-氟氰菊酯的毒性。在增强这些拟除虫菊酯毒性的植物精油中，一些精油产生了不同程度的协同作用和拮抗作用。天竺葵，广patch香和得克萨斯州雪松油产生的增效作用最高，在某些组合中共毒性因子> 100。为了评估其他种类杀虫剂的增强和协同作用水平，马拉硫磷也与植物油结合使用。