Com o objetivo de buscar alternativas no controle químico da formiga-preta-pastadeira, Acromyrmex crassispinus (Forel, 1909) (Hymenoptera: Formicidae), foram instalados quatro ensaios com formicidas em pó, em Santa Maria, Estado do Rio Grande do Sul, entre 1996 e 1998. Avaliaram-se, em formigueiros grandes (80cm ou mais de diâmetro), doses de Fentiom (50g i.a./kg), de Imidacloprid (4g i.a./kg), de Betaciflutrina (2g i.a./kg), de Clorpirifós (20g i.a./kg e 50g i.a./kg), de Deltametrina (2g i.a./kg), de Acefato (750g i.a./kg) e de Diazinom (10g i.a./kg). Acima de 30g do produto comercial, foram eficazes no controle de formigueiros grandes da formiga-preta- pastadeira, as formulações em pó de Fentiom (50g i.a./kg), de Clorpirifós (20g i.a./kg e 50g i.a./kg) e de Diazinom (10g i.a./kg). Acefato (750g i.a./kg) comportou-se como eficiente com base em 3g/ninho e Deltametrina (2g i.a./kg), com 5 g/ninho em época de estiagem e, 30g/ninho, em período chuvoso.
Four experiments were carried out to evaluate the efficiency of some powdered formicides on the control of the black leaf cutting ant, Acromyrmex crassispinus (Forel, 1909) (Hymenoptera: Formicidae), in Santa Maria county, from 1996 until 1998. Powdered formicides containing Fenthion at 50g a. i./kg, Imidacloprid at 4g a. i./kg, Betacyfluthrin at 2g a. i./kg, Chlorpyrifos at 20g a. i./kg and at 50g a. i./kg, Deltamethrin at 2g a. i./kg, Acephate at 750g a. i./kg and Diazinon at 10g a. i./kg were evaluated on big nests (>80cm of diameter). The big nests of this ant were efficiently controlled with 30g/nest of the commercial formulations of Fenthion, Diazinon and Chlorpyrifos (20g a. i./kg and 50g a. i./kg); with 3g/nest of the formulation of Acephate; with 5g/nest in dry season and 30g/nest in wet season of the powdered formulation of Deltamethrin.
