Modified Atmosphere as an Alternative Measure for Controlling of Sitophilus oryzae Reared on Different Stored Grains

Abstract

Protection of grains and their products from insect pests remained a big constraint in the way of food security. Current study evaluated the effective exposure time to kill the Sitophilus oryzae (L.), reared on two different diets viz., wheat and maize under six Carbon dioxide (CO2) concentrations. Modified atmospheres (MA) contained 25, 30, 35, 40, 45 and 50% CO2 by volume at ambient temperature, respectively. Twenty S. oryzae adults, along with a 20 g diet, were released in each airtight exposure chamber (150 mL capacity). A measured quantity of CO2 gas (99.9%) was released in exposure chamber by the injection syringe from gas cylinder. Mortality data were recorded after 24, 48, 72, 96 and 120 h. The mortality rates varied between the insect cultures reared on maize and wheat diets. S. oryzae, reared on a wheat diet, showed higher mortality after exposure to all CO2 concentrations as compared to the insect culture reared on the maize diet. At 45% CO2concentration, maximum mortality (100%) was observed after 120 h in case of maize reared insects and (100%) after 96 h in case of wheat reared S. oryzae. The results revealed that Carbon dioxide, as an eco-friendly approach, may be used as the best alternative method to minimize the pest infestation in stored products to avoid insecticide resistance development in stored grain insect pests. The Carbon dioxide is not included in the category of toxic gases and has no detrimental or residual effect in the stored grains