Association of zein nanoparticles with botanical compounds for effective pest control systems.

Background: Botanical compounds from plant species are known to have pesticidal activity and have been used in integrated pest management programs. The varied spectrum of the pesticidal action of these compounds can also avoid selection of resistance in pest populations. In this study, mixtures of the botanical compounds geraniol, eugenol and cinnamaldehyde were encapsulated in zein nanoparticles to improve their stability and efficiency. Biological effects of the nano-scale formulations of the botanical compounds were evaluated against two agricultural pests: the two-spotted spider mite (Tetranychus urticae) and the soybean looper (Chrysodeixis includes).

Results: The formulations were stable over time (120 days) with a high encapsulation efficiency (>90%). Nanoencapsulation also provided protection against degradation of the compounds during storage and led to a decrease in toxicity to non-target organisms. The release of the compounds (especially eugenol and cinnamaldehyde) from the nanoparticles was directly influenced by temperature, and the main mechanism of release was through a diffusion-based process. Nanoencapsulated compounds also showed superior efficiency compared to the emulsified compounds in terms of repellency and insecticidal activity.

Conclusion: The findings of this study indicate that the convergence of botanical compounds with nano-scale formulation has the potential to improve efficacy for their sustainable use in integrated pest management in agriculture. © 2019 Society of Chemical Industry.