C. limon Peels Based Nano-Bio pesticides: Formulation and Bioactivity against the Stored Pests and Microbes

Abstract Post-harvest losses due to stored grains being compromised by insects, microorganisms, and environmental factors pose a significant challenge. These losses canbe both quantitative, affecting nutritional value, and qualitative, leading to commercial loss. Effective pest control measures, including monitoring and early detection of infestations, are essential to protect stored grains.In this study, Citrus limon peels were selected for their biological activity and commercial viability and were processed into a nano-suspension. The acute toxicity and repellency of thesenano-formulations were tested against key stored product pests such as Oryzaephilus surinamensis , Tribolium confusum , and Sitophilus zeamais , alongside their antimicrobial activities. The developed nano-suspension exhibited optimal physical characteristics (particle size = 147.4 nm; PDI = 0.47). This formulation was repellent over time in area preference bioassays. Laboratory trials demonstrated that C. limon nano-suspension achieved a 100% mortality rate against O. surinamensis and S. zeamais , and an 80% mortality rate against T. confusum . Additionally, the C. limon peels-based nano-biopesticides exhibited high antimicrobial activity against bacterial pathogens ( Pseudomonas syringae and Clavibacter michiganensis ) and fungal pathogens ( Fusarium oxysporum and Rhizopus stolonifer ). These results indicate that C. limon peels-based nano-biopesticides, with their high dissolution rate, serve as effective antimicrobial agents and repellents, offering a promising alternative to chemical pesticides for controlling phytopathogenic species.