“Erva mate” is a native tree, which is very important for the gaucho culture mainly because it serves as raw material for the traditional mate, and other products. Due to the high disease incidence in the “erva mate” plantations and nursery, the lack of information related to the pathogens that occur in this culture and its proper management, many farmers have abandoned these areas to cultivate major crops. This study aimed conduct a survey and identification of major diseases that occur in “erva mate” in the Alto Uruguai Gaucho region. For this, soil samples were collected for posterior serial dilution and quantification of colony forming units (CFUs), and aerial part samples of unhealthy plants for later identification of present pathogens. In the aerial part samples, it was found that the highest incidence in “erva mate” plantations and nurseries was the Fusarium genus, and also identified genre fungi as Colletotrichum, Cylindrocladium and saprophytes as Rhizopus and Cladosporium. Furthermore, it was evident the presence of genus Trichoderma in the soil samples, which is important since this is an antagonist of Fusarium species that are potentially pathogenic to this culture.