Thesis (Ph.D.) - Cairo University - Faculty of African Postgraduate Studies- Department of Natural Resources

Early symposium disease is considered one of the most important diseases affecting the tomato crop and causes great losses in the world. A total of 65 isolated were selected for the different regions and different seasons. A genetic definition was performed using three regions of the gene (Alt-a1, GAPDH, and RPB2) to determine their degree of similarity. Select of 15 isolates were from among the 65 isolates for which the identification of genetic in order to carry out the other experiments with numbers (9, 11, 14, 18, 21.19, 33, 38, 40, 44, 146, 148, 154, 160 and 164). 14 isolates belong to section Alternaria alternata and one isolate section Alternaria arborescens. Pathogenicity test of 15 isolates on the laboratory and greenhouse, Showed results the isolate number 154 the highest aggressive, while, the least aggressive isolation number 44. Study the effect of different media on mycelium growth, showed 15 isolates that they all grow over a wide range of nutrients added to the environment. The extraction of different toxins produced by the different isolates and the result of the analysis of the presence of the following toxins (Altenuene - Altertoxin - Alternariol - Tenuzonic acid). The experience of the division of different varieties showed a clear variance in the degree of susceptibility to the disease. Six pesticides were tested for their effect on inhibition of mycelium growth in laboratory, greenhouse and in the field

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