Integrating inert dusts with carbon dioxide as an ecofriendly approach for the control of Trogoderma granarium everts

Abstract The khapra beetle, Trogoderma granarium Everts, is one of the most destructive primary insect pests of stored grains in temperate and tropical regions. Efficacy of carbon dioxide (CO 2 ) and three inert dusts alone, and in binary combinations was conducted against Trogoderma granarium Everts on stored wheat grain. The combined treatments of carbon dioxide and inert dusts were significantly more toxic to the larvae than the single treatments after 7, 14 and 21 days of treatment. Moreover, the treatments with the mixtures of carbon dioxide with diatomaceous earths or kaolin showed greater insecticidal activity against larvae than treatments with carbon dioxide /zeolite mixtures. The highest concentrations of binary mixtures of carbon dioxide at 40% with inert dusts (kaolin, diatomaceous earths and zeolite) at 1000 mg/kg caused mortality of larvae (95.3, 84.0 and 43.8%), respectively, after 21 days of exposure. All treatments caused significant decrease in adult emergence after 80 days of treatment with carbon dioxide (40%)/ kaolin (1000 mg/kg) combination being the most effective one as it resulted in a total suppression of adult emergence. All mixtures of carbon dioxide and inert dusts particularly (kaolin and diatomaceous earths) protected wheat grain against Khapra beetle damage for 80 days without any adversely effects on wheat seed germination.