Potential application of chitosan-based nanoparticles containing essential oils against mosquitoes, moths and beetles

The association between the use of synthetic insecticides and the appearance of resistant insects, human poisoning and the environment contamination generated the need to develop new forms to pest control, and essential oils stand out as an alternative. However, due to their volatility and instability, their use in native form is unfeasible. It is possible to circumvent these problems by their encapsulation, and the use of polymeric nanoparticles for this purpose has many advantages, since these systems prevent the oil degradation, and control its release. The first in vivo trials of chitosan nanoparticles containing essential oils with insecticidal activity were published in the late 2010s. Considering the growing interest in this subject, as can be seen from the increase in the number of publications, this review aimed to gather all the papers that presented biological assays using essential oils encapsulated in chitosan nanoparticles against insects. Further, the techniques used to prepare these nanoparticles are also discussed. It was possible to note that the technique called complex coacervation led to smaller particles and most articles describing in vivo tests of chitosan nanoparticles containing essential oils assess their larvicidal activity. Among the tested nanoparticles, the one that had the best larvicidal activity in acute toxicity tests were those obtained by complexing of chitosan with cashew gum and those with the best residual activity were the cross-linked with glutaraldehyde. Chitosan nanoparticles containing essential oils also increased their insecticidal activity in toxicity tests against adult beetles.