Essential oils – promising active ingredients of botanical insecticides or hidden risks for non-target organisms?

Essential oils (EOs) are liquid mixtures of botanical ori- gin and, very often, of complex chemical profile obtained from aromatic plants. Their chemical components are synthesized in plants using few biosynthetic routes and belong mostly to the terpenoid and phenylpropanoid groups. EOs have become firmly established over the past two decades as effective tools in crop protection and public health. Their insecticidal efficacy against target pests is well documented, and their biodegradability, low environmental persistence, and high chemical complexity make them attractive alternatives to synthetic pesticides. Consequently, EO-based products are often perceived as environmentally friendly, and their evaluation has tradi- tionally focused primarily on efficacy and acute toxicity toward target organisms. Increasing evidence, however, indicates that the ecological role of EOs in agroecosys- tems is considerably more complex. However, as pointed out by Guedes et al. (2026a, b), even natural pesticides may exert significant side effects on non-target arthro- pods, which highlights the need for a more comprehen- sive assessment of their ecological impacts. Beyond pest suppression, EOs may exert both negative and positive effects on non-target arthropods through behavioural and chemosensory mechanisms.