The damage caused by the soybean cyst nematode, Heterodera glycines, not only limits expansion of the soybean (Glycine Max) crop but also reduces the yield of soybeans in Brazil. Knowledge of the spatial distribution of this pathogen is needed in order to establish management measures. This study was conducted in Florínea County, São Paulo, Brazil, in a commercial soybean field, cultivar BRS133, previously known to be infected with H. glycines. In order to see the pattern of the spectral response of plants attacked by the phytonematode, field spectroradiometry measurements in the visible and near infrared regions of the electromagnetic spectrum were obtained 112 days after sowing. At the same time, soil samples were taken to the "Laboratório de Nematologia do Departamento de Fitossanidade da Universidade Estadual Paulista Júlio de Mesquita Filho, Campus de Jaboticabal", where they were processed and where the population density of the nematode was determined. The spectroradiometric measurements were transformed to the normalized difference vegetation index (NDVI) that was related to population density of the nematode, to fresh biomass and to pods per plant. It was observed that different population densities are directly related to the spectral response of the plants expressed by NDVI values.
