Comparative Effects of Carbon Dioxide Concentration in Modified Temperature and Pressure Conditions on Adults and Larvae of the Red Flour Beetle, Tribolium castaneum (Herbst) (Coleoptera: Tenebrionidae)

Abstract

Three modified atmospheres with different CO2 concentrations (30, 40, and 50%) were tested against larvae and adults of the red flour beetle, Tribolium castaneum (Herbst), at 25 and 35 °C by using several exposure periods to detect the mortality percentages and lethal time (LT) values. The effect of CO2 under pressure (5, 10, and 15 bars) on the target insect was also evaluated at 25 °C and two exposure periods. Larval and adult mortality of 100% after four days at 35 °C was obtained with the modified atmosphere containing 50% CO2. The LT50 for adults was 6.8 days at 30% CO2 concentration and 25 °C and decreased to 1.8 days with 50% CO2 concentration at 35 °C, whereas larval LT50 was 3.9 and 0.8 days at the same CO2 concentrations and temperatures, respectively. At the highest tested CO2 concentration, significant larval sensitivity was observed after the first two days of exposure. Using CO2 under 15 bar pressure decreased the necessary exposure period to attain 100% mortality of adults and larvae from several days at normal pressure experiment to five hours.