Effect of pneumatic conveyance of wheat on mortality of adult stored grain beetles

Abstract

study was undertaken to investigate the effect of pneumatic conveyance of wheat on mortalities of the adults of the two most common insect species of stored grain in Canada. Hard red spring wheat infested with red flour beetles, Tribolium castaneum (Herbst) and rusty grain beetles, Cryptolestes ferrugineus (Stephens) at grain moisture contents of 14, 17, and 20% (wet basis) was conveyed using a pneumatic conveyor at flow rates of 3.5 and 5.0 t/h. Samples of grain were collected at three points along the grain flow path and were analysed for insect numbers. Wheat passed through the conveyor was also evaluated for any loss in germination. Insect mortality as high as 98% was achieved for both species after a single pass through the pneumatic conveyor. In the range of 3.5 to 5.0 t/h the effect of flow rate on insect mortality was statistically insignificant. Mortality was low at high moisture content and increased significantly as the moisture content of grain decreased. The insect mortality also increased with an increase in the length of the flow path and introduction of bends in the pipeline. There was no adverse effect of pneumatic conveyance on seed germination even after conveying the grain three times.