A field trial was conducted to evaluate the performance of the insecticide chlorpyrifos in two formulations, emulsifiable and granular, for the control of Diabrotica speciosa (Germ.) (Coleoptera:Chrysomelidae) in potato. The field trial was conducted during the spring season when incidence of insect pests and, consequently, damage are high in Rio Grande do Sul state, Brazil. The different dosages and formulations of insecticides were applied in the planting furrow utilizing chlorpyrifos (2, 3 and 4l i.a./ha of Lorsban 480 CE and 2 and 3kg i.a./ha de Lorsban 10G) and the standard phorate (2kg i.a./ha of Granutox 50G). Best field control performances were obtained with Granutox 50G, in the dosage of 2kg i.a./ha; Lorsban 10G, 3 and 2kg i.a./ha, followed by Lorsban 480 CE, 4 and 3l i.a./ha.
Solanum tuberosum; chemical control; soil pests
