This study explores the use of custard apple (Annona squamosa L.) seed oil, a commonly discarded by-product, as a natural insecticide against the stored grain pest Sitophilus granarius. An oil-in-water nanoemulsion was prepared in three concentrations (4%, 8%, and 12%) and tested at different working concentrations using two methods: poisonous food and contact bioassays. Insects were exposed to treated grains and filter papers, and mortality was recorded over 10 days. Results showed that insect mortality increased with concentration and exposure time. The 12% formulation was most effective, with lower LC50 values and higher relative toxicity compared to standard malathion. Probit analysis confirmed strong dose-response relationships. Use of synthetic insecticides and insect resistance is growing challenges of modern era. At that time, the study gave us a way to overcome from low efficacy of essential oil, and also shows us that custard apple seed oil could be a natural, eco-friendly alternative to chemical insecticides. Plus, it highlights how we can make use of agricultural by-products for more sustainable pest control solutions.

Nanoemulsion, Custard apple oil, Sitophilus granarius, Dynamic light scattering, polydispersity Index, GC-MS

This study shows that custard apple seed oil, often thrown away as waste, can be turned into a powerful and eco-friendly insecticide when formulated as a nanoemulsion. When tested against Sitophilus granarius, a common pest of stored grains, the nano emulsion especially at 12% concentration proved highly effective. It caused significant insect mortality in both food-based and contact exposure methods, even outperforming the chemical insecticide malathion in some cases. The results highlight the potential of using natural, plant-based materials for safer pest control. Turning a discarded seed into a useful product not only reduces waste but also offers a sustainable alternative to harmful chemicals. With further testing and real-world application, this formulation could offer a practical solution for protecting stored grains in an environmentally responsible way.

Manoj Kumar Meena, Deepak Rajpurohit, Devendra Jain, Basanti Lal Baheti, Amit Trivedi and Anil Kumar Vyas (2025). Insecticidal Efficacy of Custard Apple (Annona squamosa L.) Seed Oil-Based Nanoemulsion Against Sitophilus granarius (L.). Biological Forum, 17(9): 104-111.