Are We Adequately Testing Essential Oils as Insecticides in the Laboratory? Bridging the Gap Between Laboratory Bioassays and Field Applications

Essential oils (EOs) have been extensively studied as potential alternatives for insect pest management. In recent years, research on these natural compounds has increased substantially. However, despite numerous studies demonstrating the insecticidal properties of EOs under laboratory conditions, their practical application remains limited. This discrepancy highlights a significant gap between experimental findings and the development of commercially viable products. Several factors have been proposed as the basis for this gap, including the absence of positive controls to compare their effectiveness (i), the imperative need to develop new formulations (ii), and the potential toxicity of many to non-target organisms (iii). This work focuses on why the information obtained in the laboratory has not translated into the biopesticide market. A key issue is the difficulty of applying laboratory knowledge in adapting to field-like scenarios, such as spray quality (droplet size and volume), the nature of the application solvent used in the sprayer tank, and the way the insect is exposed to the insecticide (i.e., the type of laboratory bioassay selected). This challenge is primarily due to researchers’ limited understanding of the application techniques used in field settings to manage specific insect pests. Many laboratory bioassays designed to measure effectiveness do not accurately reflect field conditions; instead, they often create scenarios that artificially enhance effectiveness. This results in an unrealistically high effectiveness estimate of the true potential of EOs in controlling the targeted insects.