ABSTRACT The temporal and spatial patterns of Phytophthora infestans population genetic structure were analyzed in the Del Fuerte Valley, Sinaloa, Mexico, during the crop seasons of 1994 to 1995, 1995 to 1996, and 1996 to 1997 by geographical information systems. Isolates of P. infestans were obtained from infected tissue of tomato and potato collected from two areas: (i) where both potatoes an...