Incidence of potato purple top, and abundance of its vectors, the potato psyllid, Bactericera cockerelli (Sulc) (Hemiptera: Psyllidae), and leafhoppers (Empoasca spp. and Macrosteles spp.) were monitored in three production sites and four crop cycles (2004–2007) in the potato, Solanum tubersum L., growing region of Coahuila and Nuevo León, México. There was a linear relationship between the annual incidence of potato purple top, and abundance of potato pyllid and leafhoppers. Results showed the importance of the vectors in dissemination of potato purple top in the region. Potatoes planted before the middle of May are exposed to more abundant vectors. The least risk of disease occurred when the potato plant emerged between June and July, when the insects were scarce. Arrival of vectors to the production site did not always coincide with disease outbreak, which suggests seed potatoes are the main initial source of inoculum for potato purple top.