This study investigated the phytochemical analysis and bio-insecticidal effect of lemongrass extract (oil) on the control of weevils (Callosobruchus maculatus) infesting stored beans in Nkwo Market, Mgbakwu, Anambra State. The phytochemical analysis revealed the presence of citral, geraniol, alkaloids, flavonoids, and phenolic compounds, while cyanogenic glycosides, betalains were absence in the lemongrass extract oil. The results of the bio-insecticidal effects of lemon grass extract on weevil mortality in stored beans. The results showed a significant dose-dependent increase in weevil mortality, with concentrations of 4ml, 6ml, 8ml, and 10ml achieving 70-100% mortality rates within 1-3 days. In contrast, the control group (0ml) showed 0% mortality throughout the study. The highest concentration (10ml) achieved 100% mortality within 2 days, demonstrating the potential of lemon grass extract as a natural insecticide. Further research is needed to optimize the concentration and exposure time, understand its mode of action and potential side effects, and evaluate its efficacy in real-world scenarios. Future studies should focus on phytochemical analysis to identify active compounds, real-world efficacy testing, and development of suitable formulations and application methods. This research aims to provide a comprehensive understanding of lemon grass extract’s bio insecticidal effects and its potential as a sustainable and effective solution for controlling weevil populations in stored beans, ultimately contributing to food security and sustainable agriculture practices.