The efficacy of different surface applications of wettable powder formulation of Detech® diatomaceous earth against the rice weevil, Sitophilus oryzae (L.) (Coleoptera: Curculionidae)

In this study, the insecticidal activity of the wettable powder formulation of Detech (R) diatomaceous earth against the rice weevil, Sitophilus oryzae (Coleoptera: Curculionidae), an important stored grain pest, was investigated. Detech (R) diatomaceous earth was applied on concrete and wooden surfaces at doses of 0.25, 0.5,1 and 2 g/m(2) and the mortality of S. oryzae adults was observed at time intervals of 24, 48, 72, 96,120, 144, 168, 192, 216, 240, 264 and 288 h. In the first 24 h of application on the concrete and wooden surfaces, no death was observed. At the 48th hour, no effect or very low mortality was observed on the concrete and wooden surface at all doses. While the increase in dose and exposure time on the concrete and wooden surface increased the mortality rate of the adults, complete adult mortality was obtained on concrete surfaces after 288 h. The wettable powder formulation of Detech (R) diatomaceous earth at a dose of 2 g/m(2) is highly effective against rice weevils on wood and concrete surfaces at laboratory conditions, though with greater success on concrete, but the longer DE exposures increase the efficacy on both surfaces. (C) 2020 Elsevier Ltd. All rights reserved.