Contribution à l’étude d’alternaria sp., agent causal de l’alternariose de la pomme de terre : Prospection, isolement et identification du pathogène

Abstract

Alternaria is one of the most common fungul genus that includes speices that can be saprophytic, endophytic or pathogynic. On potato as phytopathogens, they can cause serious problems and economic losses for farmers. In this study, we selected 4 isolates of alternaria for idebtification. The morphological ceiteria revealed the presence of two speices of Alternaria : Alternaria alternata, Alternaria tinuissima. The study of abiotic conditions shows a better growth of the pathogen  On medium extracted leaves of plat potato by contricution by other media (PCA and Malt Agar)  An incubation temperatue of 28°C. The pathoginicity test revealed the virulance of these 4 isolated with respect to six potato varieties with a degree that wich differs from one variety to another . The results of the postulat of koch for the evaluation of the severity of alternaria. Show that the four selacted fungal (S1, S2, S3, S4) is selected cause the disease.