Efficacy of attapulgite, applied alone or in combination with oregano oil, against the granary weevil, Sitophilus granarius (L.), on three grains

The use of inert materials have been proposed as viable alternatives of traditional neurotoxic insecticides and fumigants. In this work, we examined the insecticidal effect of attapulgite, applied alone or in combination with oregano essential oil, for the control of adults of the granary weevil, Sitophilus granarius (L.) (Coleoptera: Curculionidae), on three different grains, i.e. wheat, rice and barley, and at two temperatures, 25 and 30 degrees C. The increase in the temperature increased adult mortality, but progeny production, in most of the combinations tested, was not much affected. The combined use of attapulgite with oregano did not increase adult mortality much, as compared with the application of attapulgite alone. In general, adult survival, along with high progeny production, was recorded, even when attapulgite, either alone or in combination, was applied at the highest dose rate (1000 ppm), regardless of the commodity. Our data demonstrate that such an application can be further tested at elevated dose rates and for longer exposure intervals.