Effectiveness of various combinations of three main gases (oxygen, carbon dioxide and nitrogen) through modified atmospheres on pulse beetle, Callosobruchus maculatus (F) population in stored green grams

Pulse beetles, Callosobruchus maculatus (Coleoptera: Bruchidae) are among the most important insect pests of stored green gram or mung bean (Vigna radiata) in India. Control of this pest generally relies on the use of synthetic insecticides. Insecticide usage in long-term storage of green grams has been problematic for years due to health and environmental concerns. The use of modified atmospheres may be an alternative for the control of C. maculatus in stored green grams. Hence, this study was conducted to evaluate the efficacy of modified mixtures of three main gases, oxygen, carbon dioxide and nitrogen (CO2, N2 and O2) on the population of C. maculatus in stored green grams in laboratory conditions. Experiments with different gas ratios and over different exposure times (3, 5, and 7 days) were evaluated. The results revealed that a 3% O2 + 40% CO2 + 57% N2 combination was the most effective causing 100% mortality and a decrease in oviposition (1.9 eggs/female) compared to the control (20 eggs/female) after an exposure period of 7 days. In general, the effectiveness depended on the rise of CO2 and reduction of N2. The overall results suggest that pulse beetles can be managed through increasing CO2 and reduction of N2 in bean storage facilities. This would allow phasing out insecticides in bean storage, ultimately leading to safe food.