Isolation process carried out from tomato plants in different locations shown a typical 
leaf spot grown in commercial open fields grown in El-Minya Governorate. This process 
revealed 10 isolates designated from Als1 to Als 10. In general, the tested isolates are able to 
infect tomato plant genotype Syria 084 and the highest virulence one is Als 4. All tested 
Alternaria isolates produced conidiospore contained about 3.9-5.2 cells (mean 4.6), length 
120-151 µm (mean 131 µm) and 42.2-55.1 µm width (mean 51.0. µm). The length/width 
ratio was ranged from 2.6 to 3.1 with mean 2.8. The measurements referred that the isolated 
pathogen is typically A. alstroemeriae. This identification was confirmed by PCR as a 
molecular identification. 
Out of 7 tomato genotypes, Syria 084 shows high susceptible one followed by F1 023. 
The highest resistant genotype was F1 K-186 followed by Sajda. The isolated A. 
alstroemeriae can infect 3 plants belong to Family Solanaceae i.e. Solanum tuberosum 
(potato cv. Pinto), Capsicum annuum (pepper cv Ropy King) and Solanum melongena 
(eggplant cv Baldy Black). On the other hands, Datura stramonium was resistance toward the 
fungus infection. Actymal 70% shows the highest inhibitory effect on the fungal growth 
compared to Cure M 45 and Metrodex 80%. Also under field condition, it shows the highest 
protection effect for tomato plant against A. alstroemeriae.