Application of Food-Grade Inert Dust in Grain Store Houses with Inner Circulation

The combination of the food-grade inert dust and inner circulation system was applied in a large warehouse (50 m length,30 m width,and 6 m grain height) to improve the pest control effect.The ventilation speed of per unit area,the total resistance of the inner circulation system,the distribution of inert dust within 0.9 m depth below the surface of grain bulk,and the pest control effect were measured.The results indicated that the ventilation speed of per unit area was 0.001 6 m/s and the total resistance of the inner circulation system were 300.2 Pa.The inert dust particles were able to penetrate the grain bulk at 0.3 m depth with the concentration of (2.96±0.59) mg/m³,however,the concentration was zero at 0.6 m and 0.9 m depth.The corrected mortality of 3 species of Cryptolestes reached 100% after 7 d,and the difference was not significant.The corrected mortality of Sitophilus zeamais and Rhyzopertha dominica was (84.8±4.7)% and (56.5±2.3)% respectively after 8 d.The corrected mortality of Tribolium castaneum was (65.0±3.6)% after 11 d.Applying inert dust in combination with the inner circulation reduced the labor intensity and had a good pest control effectiveness,so it could be applied widely in the future.