Abstract

ESCALANTE ORTIZ, Marlyn  and  FARRERA PINO, René. Potato late blight (Phytophthora infestans Mont De Bary) epidemiology in producer areas of Táchira State, Venezuela. Bioagro [online]. 2004, vol.16, n.1, pp.47-54. ISSN 1316-3361.

To know the potato late blight epidemiology in the producer areas of Táchira State, Venezuela, three field experiments were conducted. Two of them in Pernía village and the other in El Cobre area, where the disease progress curves and infection rates (K) were obtained. The favorable effect of environment to epidemic occurrence was evaluated by calculating of severity values (SV) and favorable days to late blight (FDLB). Multiple regression was used to study the environmental effect on disease. The first experiment was carried out under traditional management using fungicides but they were excluded in the following two trials. K values were always high, ranging between 0.14 and 0.40, and making evident the aggressiveness of the pathogen. SV and FDLB were unsuitable to predict the epidemic. The model that best explained the environment influence on disease was X = 5.955 - 0.014 P - 0.259 Tmax (R2 = 0.781), where X is the diseased plant proportion, P the precipitation and T the temperature.

Keywords : Epidemic; disease progress curves; infection rates; climate; Solanum tuberosum.