Formulation of Mentha piperita-Based Nanobiopesticides and Assessment of the Pesticidal and Antimicrobial Potential

The excessive use of synthetic pesticides has detrimental impacts on humans, non-target organisms, and the environment. Insect pest management strategies are shifting toward biopesticides, which can provide a feasible and environmentally friendly green solution to the pest problem. The key objective of the present research work was the preparation of Mentha piperita-based nanobiopesticides with enhanced stability, solubility, and pesticidal potential. Nanobiopesticides based on the Mentha piperita extract were prepared using the antisolvent precipitation method. The central composite design of response surface methodology (RSM) was utilized to optimize different process parameters, e.g., the amounts of the stabilizer and plant extract. The nanosuspension of Mentha piperita prepared with the stabilizer SLS showed a particle size of 259 nm and a polydispersity index of 0.61. The formulated biopesticides in the form of nanosuspensions showed good antibacterial activities as compared to the Mentha piperita extract against two phytopathogenic bacterial strains, Clavibacter michiganensis and Pseudomonas syringae. The M. piperita nanosuspension had higher antifungal efficacy against A. niger and F. oxysporum than the Mentha piperita extract. The M. piperita extract and its nanosuspensions were tested for pesticidal activity against the stored-grain insects Tribolium castaneum and Sitophilus oryzae. Mentha piperita-based nanobiopesticides demonstrated significantly high (p  <  0.05) average mortality of 84.4% and 77.7% against Tribolium castaneum and Sitophilus oryzae, respectively. Mentha piperita-based nanobiopesticides showed enhanced pesticidal potential and could be used as a good alternative to synthetic chemical pesticides.