Considering that the grain temperature may influence the exposure time of the fumigants, the present study was carried out to investigate the influence of increasing temperatures of the grain mass (20, 30, 35 and 40 ºC) on the exposure time to ozone required to kill 50 and 95% of adult insects of Tribolium castaneum (Herbst) (Coleoptera: Tenebrionidae). Maize grains were distributed in cylindrical polyvinyl chloride recipients having connections for gas injection and exhaustion. The insects held in cages were placed at the median height of the grain mass in each recipient, which was then fumigated with ozone at the concentration of 50 ppm. The lethal times (LT50 and LT95) for adult insects of T. castaneum were reduced by increasing grain temperature, from 20 to 30 ºC; however, at 35 ºC the lethal times were not reduced compared with lower temperatures; but at 40 ºC the exposure time decreased again, resulting in lower LT95.
ozonization; grain insect pests; storage
