Impacts of gamma radiation, as hygiene physical control agent, on population growth of Tribolium castaneum (coleoptera: Tenebrionidae) in wheat flour

Abstract

Traditional control agents are usually inconvenient for managing Tribolium castaneum especially in sensitive stored products such as milled flour where those agents may cause its spoilage or have detrimental effects on health of consumers. Gamma radiation of Cobalt-60 may be hygiene, safe and effective physical control agent for controlling T. castaneum that low gamma radiation doses can save physicochemical aspects of milled wheat flour. Therefore, effects of low doses (0, 10, 30, 50, 70 and 90 Gy) of gamma radiation were examined on survivability, development, formation and normality of developmental stages of rust red flour beetles (larvae and pupae) and on emergence and mortality of adults. Furthermore, their direct and consequent sterilizing effect on adults was also concerned. Irradiated larvae with gamma radiation doses 70–90 Gy reduced larvae numbers up to 100%. A dose of 70 Gy was also sufficient to cause completely inhibition for next pupal development, while a dose of 50 Gy was sufficient to cause completely inhibition for consequent adult emergence. Although, 67.41–81.02% of emerged adults from irradiated pupae with radiation doses 70–90 Gy were dead or deformed, gamma radiation dose of 90 Gy was sufficient to cause complete sterility for healthy emerged adults. Irradiating adult populations with doses ranged between 50 and 90 Gy reduced adult population growth 75.00–87.50%. A dose of 30 Gy was considered as effective and economic dose for reducing 94.41–99.50% of progeny production of irradiated adults. Thus, gamma radiation dose of 90 Gy may be optimal dose to reduce the pest population and prevent the pest recovery, by killing and inhibiting development of immature stages and causing complete sterility of mature stage.

Keywords

• Tribolium castaneum
• Gamma radiation
• Survivability
• Sterility
• Flour
• Control