Papaya Sticky Disease (PSD) is caused by a whitefly-borne virus and is one of the most important problems of the papaya (Carica papaya) industry in Brazil, causing yield losses of up to 100%. In order to better understand its epidemiology and generate data for studies on influence of cultural practices and bioecological features on disease dynamics, 15 papaya orchards were evaluated in Eunápolis, Bahia (Rain Forest Region) and Petrolina, Pernambuco (Semi Arid Tropics) between January 2000 and March 2001. The areas were mapped taking into consideration the row or column position of each plant and its disease status. A given plant was considered diseased when it's fruits showed latex exudation, fluid latex and latex spots. The maps were analised by ordinary runs, dispersion index, Taylor law fitting and isopath areas. Results showed greater aggregation within rows than across rows which can be the consequence of a vector limited movement, with a trend to colonizing nearest plants; The dispersion index indicated a medium to strong aggregation within sub areas and this result was confirmed by Taylor law fitting. In most of the areas, higher disease incidence was detected at orchard edges. This may indicate that vector migration can assume important role in PSD virus dissemination. In some cases it was possible to detect the presence of isolated foci inside orchards, an indication of vector colony formation and plant to plant transmission from secondary inoculum. Significant differences were not observed between rain forest and semi-arid regions.
