Efficacy of Dust and Wettable Powder Formulation of Diatomaceous Earth (Detech®) in the Control of Tyrophagus putrescentiae (Schrank) (Acari: Acaridae)

Abstract

Tyrophagus putrescentiae (Schrank) (Acari: Acaridae) is a cosmopolite mite species commonly in found food and stored products. In this study, the acaricidal activity of two Turkish diatomaceous earth (DE) formulations (Detech® WP95 and Detech® Dust) were applied on a concrete surface at five different concentrations (1, 2.5, 5, 7.5, and 10 g/m2) and dead individuals were counted at 11 different time intervals (1, 3, 6, 9, 12, 15, 18, 21, 24, 27, and 30 h) at a temperature of 25 ± 1 °C and 75 ± 5% relative humidity (RH). Mite mortalities were observed after 6- and 18-hour exposure periods at all concentrations of dust and wettable powder (WP) formulations, respectively. Specifically, 100% mortality for the WP formulation was achieved at the highest concentration of 10 g/m2 after 15 h of exposure and after 27 h and 30 h for the lowest concentration. In the case of dust formulation, mortalities were observed after 3 h of exposure at all concentrations except at 1 g/m2, while a 100% mortality rate was achieved after 21 h of exposure to all concentrations and after 18 h of exposure for 7.5 g/m2 and 10 g/m2. This study indicates that both WP and dust formulations of local diatomaceous earth can cause 100% mortality in 24 h on average and can be a promising alternative to conventional chemical acaricides.