Insecticidal Effect of Bularafa Raw Diatomaceous Earth (BRDE) Against Rhyzopertha dominica (F.) on Stored Maize (Zea mays L.) and Sorghum (Sorghum bicolor [L.] Moench) Grains

Abstract

The toxicity of Bularafa raw diatomaceous earth (BRDE) to Rhyzopertha dominica adults on stored maize and sorghum grains was conducted under ambient laboratory conditions (31-34oC and 24 – 30% R.H.). The BRDE was tested at doses: 0 (untreated control), 250, 500, 1,000 1,500, and 2000 mg/kg and Protect-It® at 1000 mg/kg of grain which served as a check. Thirty (30) mixed-sex adult insects were exposed to 50 g of freshly treated grains, and mortality was observed after 7 and 14 days. The results showed that a higher number of exposed Rhyzopertha dominica adults died on maize than on sorghum, and mortality increased with an increase in dose and exposure period. After 7 days of exposure to treated maize and sorghum grains, the LD95 values were 4981 and 5890 mg/kg of BRDE, respectively. The corresponding values after 14 days were 1561 and 3206 mg/kg, respectively