Efficacy of Beauveria bassiana for control of Tribolium castaneum with reduced oxygen and increased carbon dioxide

This study investigated the effect of atmosphere modification, a widely adopted means of insect control in stored products, on the efficacy of Beauveria bassiana for one of the most difficult to control pests, Tribolium castaneum. Oxygen reduction to 5% (±1%) as opposed to CO2 elevation to 40% (±2%) for the first 72 h of fungus exposure resulted in significantly greater larval mortality than fungus exposure under ambient atmospheres. Both treatments reduced pupation of older larvae suggesting that slowed development may be a beneficial factor for fungal efficacy. CO2 elevation but not O2 reduction significantly affected the mortality of adult beetles that were exposed to the fungus. Carbon dioxide elevation significantly reduced B. bassiana’s germination and growth rates, but oxygen reduction did not.