The nematophagous fungus Monacrosporium robustum was detected, isolated and identified for the first time in Brazil, in May 1999, at the Departamento de Fitossanidade of the Universidade Estadual Paulista (UNESP), Câmpus of Jaboticabal, São Paulo, and its potential as a biological control agent of the soybean cyst nematode (Heterodera glycines) race 3 was evaluated with a scanning electron microscope (SEM). Details of the capture structures such as adhesive nets, size, septation and conidia shape, as well as nematodes captured were documented. Monacrosporium robustum produces hyaline mycelium and the capture structures are adhesive branches that rise vertically from the hyphae, averaging 10 µm in height and 5 µm in width. A gelatinous substance is freed from these structures when in contact with nematodes, capturing them. The conidia of the fungus are hyaline, fusiforme with two or four, and sometimes five, septa. The young conidia does not have septum. In laboratory, 100% of the eggs and second stage juveniles of H. glycines and the active forms of Panagrellus sp. were captured in 72 h of exposure of these nematodes to the fungus.
