Résumé:
This work consists of studying Alternaria of potato caused by Alternaria sp. Major disease of
this culture. The goal is morphological characterization through the cultural aspects of various
strains of Alternaria sp, with the Koch postulate test based on severity of symptoms using an
artificial inoculation test of detached leaves of two apple varieties. land Bartina and Spunta.
The results of the morphological and cultural characteristics showed a broad spectrum of
colony color and appearance of the mycelium. Sporulation exhibited a variability of 0.11 - 0.6
× 106 spores / ml depending on pH. This one developed well on pH6 than on pH4. The
pathogénicity test revealed the aggressiveness of the pathogen on both varieties tested. The
Spunta variety showed total susceptibility to Alternaria strains, whereas the Bartina variety
seems to be tolerant.
The results of this study seem to us to contribute to the knowledge of the morphological and
pathogenic characteristics of early blight of the potato in order to recommend an efficient
control measure in the field
