Effect of low pressure on the survival of Trogoderma granarium Everts, Lasioderma serricorne (F.) and Oryzaephilus surinamensis (L.) at 30 °C

The effects of low pressure (50 mm Hg) and various exposure times were studied on the mortality of three important storage pest insects at 30 °C as part of an effort to eliminate the need for methyl bromide fumigation to control insects in stored commodities, through development of a novel “vacuum-hermetic” technology. Insects were exposed within test chambers containing cocoa beans with a moisture content in equilibrium with 55% relative humidity and at a constant temperature of 30 °C. Three insect species were used: Trogoderma granarium, Lasioderma serricorne and Oryzaephilus surinamensis. At 50±5 mm Hg and 30 °C, the egg was the most resistant stage in all three species at the LT99 level, times needed to obtain 99% mortality being 46, 91 and 32 h, respectively. Adults of T. granarium and L. serricorne, and pupae of O. surinamensis were most susceptible. These results widen the database established to kill insects at low pressure within the framework of practical exposure times and commercially available equipment, in order to provide an effective alternative to fumigation.