The present experiment was undertaken to study the effect of X-ray radiation treatment on mortality of rice weevil (Sitophilus oryzae L.). About 500 g of clean rice inoculated with 14 adult rice weevil (T1) and 500 g of infested rice with eggs and larvae (T2) were packed in cloth bags and then placed inside polyethylene zip pouch. The samples were then exposed to X-ray radiation at 4 different doses of 50, 100, 150 and 200 gray (Gy). Dead and live insects were counted at 7, 14 and 21 days after the treatment for calculation of mortality percentage. Insect re-emergence was recorded at regular interval of one month during storage. Complete (100 %) mortality was achieved at 150 and 200 Gy treatment after 7 days of the treatment, whereas samples treated with 50 and 100 Gy showed total mortality after 21 and 14 days of X-ray treatment, respectively. Insect infestation observed after 30 days of storage and population of rice weevil increased significantly with time in control sample. Progeny was not detected up to 90 days in all X-ray treated T2 sample and insect infestation was noticed in control sample after 30 days. From the above study, it was concluded that 150 Gy X-ray treatments could control rice weevil infestation during storage. X-ray dose of 50 Gy is effective for controlling eggs and larvae of S. oryzae. Scanning electron microscopy (SEM) of X-ray treated dead insects showed that the genital organ of rice weevil was deformed as compared to naturally dead insects.
