THE EFFECT OF DIATOMACEOUS-EARTH ON GRAIN QUALITY

Protect-It is a newly developed diatomaceous earth (DE) based insectic ide for stored-grain protection and structural treatment. It has prove d 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 handlin g 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 o f Protect-It on durum wheat did not affect the properties for high-qua lity pasta production at 50 ppm and 300 ppm, and treatment of barley a t concentrations from 100 ppm to 900 ppm also showed no differences in malting quality characteristics. A different DE based insecticide, In secto(R), was used to examine the combined affect of DE and dockage on bulk density (test weight) on Hard Red Spring (HRS) wheat, durum whea t and barley. Both dockage and DE reduced bulk density. For HRS and du rum wheat, the addition of 5%, 10%, or 15% dockage mitigated (less tha n 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 diel ectric moisture values than before treatment, depending on the DE conc entration and commodity. The effect was caused by physical effect of t he dust on the grain, since wheat treated with DE had no actual loss o f moisture. Protect-It did not affect the dielectric moisture content readings with oats and maize. In field tests, wheat treated with Prote ct-It at 75 ppm and 100 ppm, concentrations that controlled Cryptolest es ferrugineus (Stephens) and reduced Tribolium castaneum Herbst popul ations, did not cause a reduction in grain flow nor did it cause an in crease in air-borne dust when grain was moved using a screw auger. Whe at treated with 300 ppm Protect-It had reduced grain-flow and caused a n increase in air-borne dust. Bulk density of the wheat was measured b efore and after a spray (wet) application at 100 ppm or dust (dry) app lication at 75 and 100 ppm of Protect-It in both laboratory and field conditions. In the field, dry application of 75 ppm reduced bulk densi ty 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.