Resumo. Mato Grosso was the Brazilian state with the largest extension in rubber tree (Hevea brasiliensis) plantation, with 45,727 hectares of monoculture in 2002. The occurrence of the "South American Leaf Blight" caused by Microcyclus ulei (Mycosphaerellaceae, Dothideomycetidae), considered the main disease of the rubber tree, is a limiting factor to the implantation of new enterprises. A promising option, the biological control, could permit the solution of this phytosanitary problem. The objective of this work was to evaluate the potential of hyperparasite Dicyma pulvinata (anamorph) on Microcyclus ulei control in comparison with the chemical control. Experiments were conducted in the field and in a greenhouse in the district of San José do Rio Claro (MT). Applications in 3 different concentrations of Dicyma pulvinata besides the active ingredients Benomyl and Mancozeb were done. In the field, the major control percentages were obtained with the pulverization of Benomyl and of 8,1 x 106 or 1,215 x 107 conidia/ml of Dicyma pulvinata. In the greenhouse, the best results were obtained with the pulverization of 2,025 x 107 or 3,037 x 107 conidia/ml.