Thesis (Ph.D.) - Cairo University - Faculty of Agriculture - Department of Plant Pathology and Physiology

The objectives of the present work were designed to isolate and identify the causal organism of tomato early blight disease and evaluate its pathogenic ability to induce disease incidence. Some biotic, i.e. Trichoderma harzianum and T. viride or antagonistic bacteria, Bacillus subtilis and Pseudomonas fluorescens and aboitic factors, i.e. essential oils, mineral salts, organic acids, chitosan and fungicides were in vitro evaluated against the growth of the pathogen in order to find out the most suitable and applicable biological and chemical methods for controlling early blight disease of tomato under field conditions. The obtained results proved that all tested bio-agents drastically reduced the linear growth of A.solani. Whereas,T. harzianum and B. subtilis showed superior inhibitory effect on fungal growth compared to T. viride and P. fluorescens. All evaluated essential oils, mineral salts, organic acids, chitosan and fungicide's concentrations significantly reduced the fungal linear growth. Chitosan caused complete reduction in linear fungal growth at concentration of 2 g/l. All tested essential oils had inhibitory effect on fungal growth, as well as the in vitro determined secondary metabolites with fungicidal or fungistatic activity, since they allow the use of natural origin compounds that are generally species specific, have low environmental persistence, and are biodegradable

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