Influence of ozone gas on the khapra beetle, Trogoderma granarium (Coleoptera: Dermestidae) in stored wheat

Khapra beetle, Trogoderma granarium Everts, 1898 (Coleoptera: Dermestidae) is one of the most notorious pests of stored grains. This study was aimed to evaluate the efficacy of ozone against 2nd and 5th instars and adults of T. granarium in stored wheat kernels under laboratory conditions. Four ozone concentrations of 300, 600, 900, and 1200 parts per million by volume (ppmv) were used. The results revealed that the LC 50 values were 249.76 ppmv for adult, 446.75 ppmv for 5th instar, and 275.30 ppmv for 2nd instar of T. granarium after 2 h exposure to ozone. No adults emerged when the ozone concentration was 1200 ppmv, while emergence was high in controls (91.20%) after a 1-h exposure period. The highest ozone concentration of 1200 ppmv resulted in strong grain protection against adult and 2nd and 5th instars, with a 0.63%, 0.73%, and 1.16% loss in grain weight, respectively. Chemical analysis of treated wheat kernels at a concentration of 1200 ppmv ozone showed no significant differences ( p > 0.05) in fat, moisture, ash, carbohydrate, fiber, and protein content of ozone-treated wheat kernels compared to untreated grain. Thus, ozone can be effectively used to control T. granarium and provides sufficient protection for stored wheat.