Effet du pH sur la croissance mycélienne et la sporulation ; Etude du pouvoir pathogène de Alternaria sp sur deux variétés de pomme de terre.

Abstract

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