MOVEMENT OF GRAIN TO CONTROL STORED-PRODUCT INSECTS AND MITES

The movement of stored grain by auger or pneumatic conveyor was evalua ted for control of stored-product insects and mites. In a pilot scale test using nine welded steel bins each holding 322 kg of wheat (Tritic um aestivum), movement of grain using an auger in three bins caused 89 % mortality of red flour beetle, Tribolium castaneum adults and 94% mo rtality of rusty grain beetle, Cryptolestes ferrugineus adults. Larval mortality of both species, based on grain samples placed in Berlese f unnels, was 100%. Pneumatic conveyance of grain in three bins caused 1 00% mortality of all stages of both insects based on grain samples and grain-probe insect traps. In field tests, infested wooden bins of whe at and corn (Zea mays) were moved by pneumatic conveyor to a truck a n d then hand-pou red into welded steel bins. A parallel test on wheat a nd corn was done using a screw auger to move the grain. Pneumatic whea t movement killed 100% of mites (Aeroglyphus robustus), T. castaneum a dults and larvae, and C. ferrugineus adults. Mortality of C. ferrugine us larvae and psocids was 79% and 83%, respectively. Augering wheat ki lled 98% of mites, 84% T. castaneum adults, 70% T. castaneum larvae, 1 4% C, ferrugineus adults, and 0% C. ferrugineus larvae. Pneumatic move ment of corn killed 97% T. castaneum adults, 72% C. ferrugineus adults and 100% of the fungus beetle Cartodere constricta. Augering corn had less effects than pneumatic movement on insect mortality. Pneumatic c onveyance of grain, especially wheat, offers an effective physical con trol for common stored-product insects.