Impact of Cassia-derived Zinc Oxide Nanoparticles on the Reproduction, Development, and Viability of Bactrocera dorsalis

The fruit fly species Bactrocera dorsalis (Hendel, 1912) (Diptera: Tephritidae) is one of the most destructive pests impacting agricultural fruit production across tropical regions. The present study investigates the impact of Cassia fistula seed extract and its biosynthesized zinc oxide nanoparticles (ZnO NPs) on various developmental and reproductive parameters of B. dorsalis. The biosynthesis of ZnO NPs was confirmed through a shift in visual appearance and UV-Vis spectroscopy, with a prominent absorption peak at 372 nm, indicative of successful nanoparticle production. Fruit flies fed on Cassia seed-derived ZnO NP-supplemented food, ranging from 0.5 to 3.0 ml concentrations, significantly reduced egg-laying capacity and hatchability compared to the control group. Fecundity decreased from 37.12 +/- 6.13 eggs in the control group to as low as 5.24 +/- 0.67 eggs at the highest concentration, and hatchability declined from 99.6% to 3.4% at 3.0 ml. Viability estimation indicated a substantial decrease in adult emergence rates, from 99.9% in the control to 5.1% at 3.0 ml. Furthermore, the duration of development was prolonged with an increase in ZnO NP concentration, from 19 days in the control group to 21 days at 3.0 ml. Significant reductions were observed in pupal weight and length across treated groups, with weights decreasing from 15.10 +/- 0.35 mg in control to 8.21 +/- 0.05 mg at the highest concentration. This study demonstrates the potential of Cassia seed-derived ZnO nanoparticles as a bio-control agent in reducing reproductive success and development rates of B. dorsalis, highlighting their application in integrated pest management strategies.