Efficacy of Ozone Gas against All Stages of Red Flour Beetle, Tribolium castaneum (Herbst) (Coleoptera: Tenebrionidae) at Different Temperatures and Exposure Periods

Abstract

Ozone efficacy (approximately of 600 Mg.hr-1) was evaluated against Red Flour Beetle’s (RFB, Tribolium castium (Herbst)) eggs, larvae, pupae and adults at different temperatures (35, 40 and 45 ° C) and exposure times (1, 2, 4, 6, 8, 10 hours) under laboratory. The control treatments included above thermal levels without ozone at the mentioned exposure periods. The results indicated ozone effectively suppressed hatching with increasing temperature. The hatch egg rates was reduced to 0 % in the treated treatments after 10 h at 45° C. However, mortality rates of RFB were increased with maximizing of the exposure time to ozone.  After 10-h exposure to ozone at the lowest temperature 35˚ C, complete mortality (100%) or few survivals of RFB were recorded in the susceptible stages (larvae and adults). Also, the complete mortality of adults and larvae resulted after an exposure to ozone at 40 ° C for 10 hours, compared than the high survival rates at the pest’s stages at 30 and 40° C, even after 10 hours of monitoring time. However the exposure time which is required to 100% mortality was decreased to 4 hours at 45 ° C, comparing to the thermal treatment only (control) which needed more time (6 h) for 100% of mortality. In conclusion, ozone application showed the efficacy on the mortality at all stages of RFB and the temperature was a potential factor enhancing the application of ozone for RFB control.