To survey and quantify the incidence of the diseases affecting cassava (Manihot esculenta) in commercial crops of the state of Paraiba - Brazil, samplings were conducted in 21 municipalities at four microregions of the state during the first semester of 2011. The detected diseases were brown leaf spot (Cercosporidium henningsii), white leaf spot (Phaeoramularia manihotis), anthracnose (Colletotrichum gloeosporioides f. sp. manihotis) and root rot (Fusarium oxysporum). The incidence varied, and the highest indexes were found for the municipalities of the microregions of Curimataú Ocidental, Sapé and Brejo Paraibano. Brown leaf spot occurred in all evaluated municipalities, followed by white leaf spot, which showed inferior percentage of affected plants. Anthracnose was detected for around 70% of the evaluated municipalities but had reduced incidence. The highest incidence of root rot caused by F. oxysporum was observed for the city Imaculada, microregion of the Serra do Teixeira.
Quantification; etiology; spots; rot; microregions
