Response of storage insect species to ClO₂ fumigation conditions

Insects damage grain during post-harvest storage. Grain loss during storage is a serious problem, especially in less-developed countries. In this study, a gaseous ClO₂ treatment was applied to four different insect species known to damage stored grains: Sitophilus zeamais (Motschulsky), Trogoderma granarium (Everts), Callosobruchus chinensis (Linnaeus), and Tribolium castaneum (Herbst). Different insect species showed different sensitivities to the same ClO₂ fumigation conditions. The 100 ppm treatment level with 24 h exposure is effective to controlling S. zeamais, T. granarium, and C. chinensis. However, to control T. castaneum, a higher concentration of the ClO₂ gas or increased exposure time is needed. The 200 ppm treatment level with 48 h exposure is effective to controlling T. castaneum.