Beyond mosquitoes—Essential oil toxicity and repellency against bloodsucking insects

Abstract

The control of insect pests and vectors is a timely challenge for public health. The prevention of bites from bloodsucking insect species is based to a large extent on the use of chemical repellents and pesticides. However, their effectiveness is currently endangered, due to the fast-growing resistance levels in the targeted vectors, besides their negative impact on human health and the environment. Therefore, natural product research has been claimed as a helpful tool to develop effective green pesticides and repellents. Among them, essential oils (EOs) extracted from plants received peculiar attention for applications in “the real world”, since they showed high efficacy, multiple mechanisms of action and low toxicity on non-target vertebrates. However, the large majority of research items published on the topic studied the potential of EOs in the fight against mosquitoes (668 research items) and ticks (155), while only a relatively limited amount (<110) focused on bloodsucking insects different from mosquitoes. This knowledge is, however, of high importance for public health, since it offers new perspectives to control important arthropod vectors, including those directly linked with the spread of neglected tropical diseases (e.g., Triatominae bugs vectoring Chagas disease) or negatively affecting the productivity of livestock worldwide (e.g., biting midges, horse flies, horn flies and stable flies). Herein, the current knowledge available on the toxic and repellent potential of EOs and selected constituents against bloodsucker insects was reviewed. Major emphasis has been devoted to the control of Diptera, covering biting midges (Culicoides, Ceratopogonidae), black flies (Simulidae), horse and deer flies (Tabanidae), horn fly (Haematobia irritans, Muscidae), stable fly (Stomoxys calcitrans, Muscidae), sandflies (Psychodidae) and tsetse flies (Glossinidae), discussing both laboratory and field evidences. Furthermore, successful attempts aimed at the control of fleas (Siphonaptera), head, body and pubic lice (Phthiraptera) as well as bed bugs (Hemiptera, Cimicidae) and kissing bugs (Hemiptera, Reduviidae, Triatominae) have been examined. In the final section, outlooks and challenges for future research have been outlined, comparing them with what has been done in mosquito and tick control science.