Suitability of Early Blight Forecasting Systems for Detecting First Symptoms in Potato Crops of NW Spain

In recent years, early blight epidemics have been frequently causing important yield loses in potato crop. This fungal disease develops quickly when weather conditions are favorable, forcing the use of fungicides by farmers. A Limia is one largest areas for production Spain. Usually, controlled using pre-established schedule calendars. strategy expensive and can affect environment agricultural areas. Decision support systems not currently place to be used farmers managing blight. Thus, objective this research was evaluate different forecasting models based on plant or/and pathogen requirements check their suitability predicting first symptoms blight, which necessary determine timings fungicide application. For this, weather, phenology symptomatology were monitored throughout five crop seasons. The appeared starting flowering stage, between 37 40 days after emergence plants. that plants offered best results. Specifically, Wang-Engel model, with 1.4 risk units Growing Degree-Days (361 cumulative units) offeredthe prediction. pathogen-based showed a conservative forecast, whereas integrated both features forecasted attack markedly later.