Studying on the efficacy of gaseous ozone to control the cowpea weevil

Cowpea weevil (Callosobruchus maculatus F.) is the most important pest of pulses & caused heavy damage to them. Based on published documents, gaseous ozone caused to mortality of some stored pest adults. In this study the effect of different concentrations of ozone (3500, 5000, 6500 ppm) gas against eggs of C. maculatus on cowpea & in the larvae stage of C. maculatus on the cowpea, green gram & chick pea & concentrations of 700, 1200 & 1700 ppm against adults of C. maculatus on the cowpea have been tested. Penetration efficacy of ozone gas in depth of 20, 40, 60 cm into the mass of cowpea, green gram & chick pea bulk for exposure times of 10 & 20 minutes onto a C. maculatus has been studied separately. Then, effect of different ozone concentrations (5500, 6500, 7500 ppm) on germination of cowpea, green gram & chick pea have been evaluated. Based on results, the concentration of 6500 ppm provided 54.8% mortality to eggs & 100, 93.3 & 36.1 percent to larvae in cowpea, green gram & chickpea respectively. Concentration of 1700 ppm induced 97% mortality to adults. Twenty minutes exposure time for adults in depth of 60 cm of cowpea, green gram & chick pea bulk resulted %72.25, %92.5, %100 mortality respectively. Moreover, 30 minutes exposure time had %100 of mortality of adults in depth of 60 cm. In addition to above results, no negative effects were observed on percentage of germination due to different concentrations of gaseous ozone.