UTTAR PRADESH JOURNAL OF ZOOLOGY

Sitophilus oryzae L., commonly known as the rice weevil, is a primary post-harvest pest of rice that causes significant quantitative and qualitative losses in stored rice each year. This study evaluated the host susceptibility and infestation potential of the insect on five indigenous rice varieties of Assam, namely Black Rice, Brown Rice, Joha Rice, Bora Rice, and Aijung Rice. These indigenous rice varieties differ in grain morphology, texture, and pigmentation. Damage progression was monitored continuously for 180 days following the initial infestation, with assessments conducted at regular intervals to capture the effects of overlapping insect generations. Kaplan–Meier survival analysis was used to estimate the time taken by each variety to reach a defined damage threshold, while the Kruskal–Wallis test was used to evaluate differences in damage progression among the selected rice varieties. The results showed statistically significant differences in resistance among the varieties (H = 11.73, df = 4, P = 0.0194). Black Rice and Brown Rice exhibited the greatest resistance, followed by Aijung Rice, which was moderately resistant; Joha Rice was susceptible, and Bora Rice was the most susceptible. The findings suggest that grain hardness, pericarp density, and biochemical composition may contribute to differential susceptibility. These findings may facilitate the selection of resistant indigenous varieties and enhance the effectiveness and sustainability of integrated stored-grain pest management strategies.