The effect of diatomaceous earth on grain quality

Protect-It is a newly developed diatomaceous earth (DE) based insecticide for stored-grain protection and structural treatment. It has proved effective at controlling stored-grain insects in laboratory tests at application rates well below other DE-based insecticides. This study examined the effect of Protect-It on quality, and physical and handling characteristics of cereals. Treatment of Hard Red Spring (HRS) wheat with either 50 or 300 ppm Protect-It had no significant effect on the milling, analytical, rheological or baking quality. The application of Protect-It on durum wheat did not affect the properties for high-quality pasta production at 50 ppm and 300 ppm, and treatment of barley at concentrations from 100 ppm to 900 ppm also showed no differences in malting quality characteristics. A different DE based insecticide, Insecto(R), was used to examine the combined affect of DE and dockage on bulk density (test weight) on Hard Red Spring (HRS) wheat, durum wheat and barley. Both dockage and DE reduced bulk density. For HRS and durum wheat, the addition of 5%, 10%, or 15% dockage mitigated (less than 1 kg/hl) the reduction of bulk density when DE was applied. Protect-It treatment of HRS wheat, rye and barley gave 0.2% to 0.8% lower dielectric moisture values than before treatment, depending on the DE concentration and commodity. The effect was caused by physical effect of the dust on the grain, since wheat treated with DE had no actual loss of moisture. Protect-It did not affect the dielectric moisture content readings with oats and maize. In field tests, wheat treated with Protect-It at 75 ppm and 100 ppm, concentrations that controlled Cryptolestes ferrugineus (Stephens) and reduced Tribolium castaneum Herbst populations, did not cause a reduction in grain flow nor did it cause an increase in air-borne dust when grain was moved using a screw auger. Wheat treated with 300 ppm Protect-It had reduced grain-flow and caused an increase in air-borne dust. Bulk density of the wheat was measured before and after a spray (wet) application at 100 ppm or dust (dry) application at 75 and 100 ppm of Protect-It in both laboratory and field conditions. In the field, dry application of 75 ppm reduced bulk density by 1.6 to 2.5 kg/hl, 100 ppm by 2.0 to 2.8 kg/hl, and 300 ppm by 4.6 to 4.8 kg/hl. Protect-It reduced bulk density by 1.5 to 2.2 kg/hl at 100 ppm wet application.