Epidemiology of tomato bacterial wilt in Agreste region of Pernambuco State, Brazil, in 1996/1997

With the objective to obtain quantitative information on the intensity of tomato bacterial wilt in the Agreste region of Pernambuco State (Brazil) 50 commercial tomato fields located in the district of Camocim de Sao Felix, the main fresh tomato producer in the Agreste region, were surveyed in relation to prevalence and incidence of the disease at flowering or fruiting stage. High disease prevalence (60%) was observed, with a mean disease incidence of 13.1%. In order to determine the disease progress and spatial pattern, four commercial fields were selected and plots containing aproximately 560 plants were studied. In two areas the disease progress was better represented by the monomolecular model, and in the other two by either the Gompertz or logistic models. The spatial pattern of infected plants was different among areas, and this pattern changed over time in three areas. These results indicate the epidemiological character of tomato bacterial wilt in the Agreste region of Pernambuco and emphasize the importance of using an integrated management program for this disease.