Insecticidal activity and persistence of a natural Cuban zeolite and a diatomaceous earth against Sitophilus granarius on wheat

Sitophilus granarius (L.) (Coleoptera, Curculionidae) is one of the main pest of stored wheat worldwide. Inert dusts can play an important role within Integrated Pest Management strategies (IPM). Diatomaceous earths are the most often tested materials for controlling stored-product pests; whilst, less information is available on zeolites. This study aimed to expand the knowledge on the insecticidal activity and persistence of a natural Cuban zeolite (NCZ) compared to a diatomaceous earth (DE). In insecticidal tests, grain samples were treated with 0.25, 0.5, 1, 2, 4, and 8 kg/ton of DE or NCZ and infested with 20 S. granarius adults. The number of dead specimens after 3, 7, 14, and 21 day-exposure and the total F1 progeny were recorded. In persistence tests, grain was treated with 0.25, 0.5, 1, 2, and 4 kg/ton of dusts, while infestation with S. granarius adults was started 3, 6, or 12 months after treatment. The NCZ treatment reached the total adult mortality at slightly higher doses and exposure times compared to DE. However, starting from 1 to 2 kg/ton doses for DE and NCZ respectively, the total insect mortality was reached within a short time and the mean progeny per replicate was below one individual. The persistence activity of NCZ and DE has been confirmed for up to 12 months from the treatment without significant differences between the two inert dusts. The NCZ appears of great interest for practical applications in controlling S. granarius.