Insecticidal efficacy of three commercial diatomaceous earths, Detech®, Demite® and Silicosec® against cowpea weevil, Callosobruchus maculatus (F.) (Coleoptera: Chrysomelidae: Bruchinae)

Abstract: In the present study, the insecticidal efficacy of three commercial diatomaceous earths, Detech®, Demite® and Silicosec® was tested against cowpea weevil, Callosobruchus maculatus (F.) (Coleoptera: Chrysomelidae: Bruchinae) at three different concentrations (500, 750 and 1000 ppm) on chickpea. Detech® and Demite® are new diatomaceous earth formulations developed in Turkey. Due to the short life span of C. maculatus adults, mortality of the adults was assessed after 1, 3, 5 and 7 days of DE exposure. Progeny (F1) production on treated chickpeas was recorded 42 days after DE treatments. Biological tests were carried out under laboratory conditions at 25 ± 1 °C, 55 ± 5% R.H. in the dark. Detech® and Demite®, were as effective in controlling C. maculatus on chickpea as Silicosec®. After 1 day of DE exposure, none of DE treatments produced complete mortality of C. maculatus while after 5 days of DE exposure, Detech® and Demite®) at 1000 ppm concentration resulted in 100% mortality of C. maculatus adults. DE treatments at 1000 ppm concentration resulted in the reductions of the progeny (F1) production, ranging from 78% to 86%.Generally, increasing DE concentration lowered the progeny production. However, none of DE treatments prevented the complete progeny (F1) production of C. maculatus. In conclusion, this study indicated that the new Turkish commercial DE formulations (Detech® and Demite®) showed relatively higher mortality of C. maculatus adults compared to commercial DE formulation, Silicosec® and can be used in the management of C. maculatus in stored chickpea.