Abstract
The effectiveness of amorphous silica dust (Dryacide) on three classes of wheat (Durum, hard wheat and soft wheat) was tested at 20°C and 30°C at 40% and 60% r.h. against adult and progeny of Rhyzopertha dominica (F.). The effectiveness of silica dust was generally greater at 30°C than 20°C and at 40% rather than 60% r.h. Toxicity of silica dust was significantly higher on durum at 40% r.h. and on hard wheat at 60% r.h. The optimum tested conditions for progeny production were 30°C and 60% r.h. The mean number of progeny produced was significantly reduced with increasing silica dust concentration from 0–500 μg silica dust/g wheat. However, increased silica dust concentration from 500–900 μg silica dust/g wheat had no increased adverse affect on progeny production.