Effectiveness of a Turkish natural diatomaceous earth formulation against rice weevil (Coleoptera: Curculionidae) on wheat and paddy

Abstract: A Diatomaceous earth formulation of Turkish origin, Turco-000, applied to wheat and paddy rice at different rates of up to 2 mg/kg, was evaluated against Sitophilus oryzae (F) on weekly basis for 21 days. Laboratory experiments were carried out at 25 °C and 55% R.H. using 9 replicates per dose rate and 20 adults per replicate. The GLM Repeated Measures ANOVA procedure was applied to the mortality results. Bonferroni multiple comparison test was employed to compare of means between the treatments at P < 0.05.On wheat and paddy rice mortality of S. oryzae increased with dose rate and exposure time and reached to 69.85% and 45.45%, respectively, after 21 days of exposure.LD50 values for S. oryzae adults exposed to DE treated wheat and paddy rice after 7 day exposure were calculated as to 1443.6 mg/kg and 3445.4 mg/kg, respectively.We conclude that Turco-000, a Turkish natural DE deposit, was more effective against rice weevil on wheat than on paddy rice.