Early blight is one of the most important diseases on potato in southern Chile. In this study we
could identify five Alternaria groups associated to potato crops (A. alternata, A. tenuissima, A.
arborescens, A. infectoria and A. solani) using morphological and molecular characteristics. At
the same time, the Alternaria spore release curve was determined using a spore trap and
accumulation of physiological days. This information could be used to predict the appearance of
the first symptoms of this disease, which would help the development of an early blight forecast
system