UTTAR PRADESH JOURNAL OF ZOOLOGY

The present study evaluated the insecticidal efficacy of Catharanthus roseus leaf powder extract against Sitophilus oryzae and its effect on reducing rice grain weight loss. Mortality and grain damage were assessed at different extract concentrations (1, 1.5, 2 and 2.5 %) over various exposure periods. The mortality rate increased progressively with higher concentrations and longer exposure durations. On the first day, mortality ranged from 4.16 to 22.91 % mortality at 1 and 2.5% cconcentrations with a significant rise by the 14th day (33.33% at 2.5%) and reaching the maximum (43.75%) on the 21st day at 2.5% concentration. Similarly, a notable reduction in grain weight loss was observed in all treatments after 21 days of infestation. The highest weight loss was recorded in the control (25.54 ± 1.198%), while the lowest occurred at 2.5% concentration (11.583 ± 0.27%). Treatments with 1, 1.5 and 2% extracts showed intermediate reductions (15.836 ± 0.15%, 13.52 ± 0.26%, and 12.666 ± 0.27%, respectively). Overall, the findings indicate that C. roseus powder extract exhibits potent insecticidal activity and effectively minimizes grain loss, suggesting a promising candidate for eco-friendly pest management strategies especially in stored grain protection.