摘要
A wide range of insect pests attacks stored sorghum grains and the significant damage in grain weight loss and negative impact on the nutritional values of sorghum are caused with the activities of these pests. The insecticides, especially from organophosphate group （OP）, are still used to prevent damage of sorghum grains during storage period. One of the possible replacements for OP and other synthetic insecticides is a natural and safe diatomaceous earth （DE）. The primary objectives of this study was conducting the laboratory experiments with enhanced DE Protect-lt on Sitophilus oryzae （L.）, Rhyzopertha dominica （Fab.） and Tribolium castaneum （Herbst.） to find out the effective concentrations and to determine the effect of applicable concentration of DE on bulk density （test weight） of sorghum grains. The effect of Protect-it on bulk density was measured at 1,000 ppm. After the exposure of S. oryzae, R. dominica and T castaneum to treated grains during 13 days, lethal dosis that causes 90% mortality （LD90） were 811 ppm, 1,102 ppm and 1,244 ppm, respectively. After exposure of 8 days the concentration of 1,000 ppm generated the mortality ofS. oryzae 100% and for R. dominica and T.castaneum for over 99%. The same concentration had a minimal effect on the reduction of sorghum bulk density （for 1.95% only）.
