Persistence of diatomaceous earth, SilicoSec® against three stored grain beetles

Abstract The persistence of a commercially available diatomaceous earth (DE) formulation (SilicoSec®) against Sitophilus granarius, Rhyzopertha dominica and Tribolium confusum on wheat at four dose rates (500–2000 mg/kg) during a 360-day period of storage was assessed. Mortality of S. granarius were 76.0, 88.4, 93.2 and 95.6% at 7, 14, 21, and 28 days, respectively at 0 month at a dosage of 2000 mg/kg, whereas the corresponding values were 31.5%,71.3, 87.2 and 96.8 at 12 months with the same dosage. Mortality of R. dominica were 48.0, 79.6, 86.4 and 90.0% at 7, 14, 21, and 28 days, respectively at 0 month at a dosage of 2000 mg/kg, whereas the corresponding values were 82.7, 95.2, 98.0 and 98.8% at 12 months with the same dosage. Mortality of T. confusum were 82.1, 96.8, 98.8 and 100.0% at 7, 14, 21, and 28 days, respectively at 0 month at a dosage of 2000 mg/kg, whereas the corresponding values were 32.8, 99.6, 100.0 and 100.0% at 12 months with the same dosage. The increase in mortalities obtained from 1500 to 2000 mg/kg for each of the three species were mostly insignificant at 28 d exposure. Therefore, wheat treated with SilicoSec® at a dosage of 1500 mg/kg could be satisfactorily protected against S. granarius, T. confusum and R. dominica for a year.