Efficient carbon dioxide fumigation of wheat in welded-steel hopper bins

Two welded-steel hopper bins were modified for fumigation with carbon dioxi de (CO2) and a method for efficiently purging the air from the bins was dev eloped. Concentrations of CO2 during experimental fumigations were less tha n the concentrations predicted theoretically, but were high enough to kill more than 99% of caged adult rusty grain beetles in three separate experime nts. Between 58 and 75% of the CO2 initially added remained in the bin at t he time when the CO2 concentrations peaked. The positive results from this research mean that stored-product insects in stored grain can be controlled using CO2 rather than continuing to rely on synthetic insecticides and fum igants that present health and environmental concerns.