الفهرس 
1- INTRODUCTIONOnly 14 pages are availabe for public view
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Abstract
A total of 112 fungal isolates taken from tomato plant showed typical symptoms of root rot disease collected during survey trails. On the base of pathogenicity test, eighteen pathogenic isolates of Macrophomina phaseolina and fifteen isolates of Rhizoctonia solani ones were chosen to represent all the six surveyed counties of Fayoum Governorate. Different tomato cultivars were found to be vulnerable to infecte by the selected virulent M. phaseolina and of R. solani isolates. All selected virulent isolates could macerate all representative cultivars tested. Total counts of tomato rhizosphere microorganisms were 35.00 ×104, 48.00 × 106 and 26.00×105 for fungal, bacterial and actinomycetes isolates, respectively. The total counts of rhizosphere microorganisms recorded 11.45 and 6.58 ×106 at Etsa and Abshoay Counties, respectively. Tested isolates of Streptomyces spp, Bacillus subtilis, Pseudomonas fluorescens and Trichoderma spp. varied in their antagonistic activity against the pathogenic isolates of M. phaseolina and R. solani. On the average, Streptomyces spp. (S6); Pseudomonas fluorescens (P5), Bacillus subtilis (B10) and Trichoderma harzianum (TH8) caused the highest growth reduction of tested pathogenic fungi, being 47.22, 26.11, 23.89 and 47.22%, respectively, comparing to check treatments. The inhibitory effect of chitosan, essential oils, salts and antioxidants components on linear growth reduction of M. phaseolina and R. solani significantly reduced the average mycelium growth of tested fungi. Fungal growth significantly decreased as increasing the tested component concentration. The antagonistic activity of salts and antioxidants components was more effective on growth reduction of M. phaseolina and R. Solani. Moreover, all tested concentrations of Salicylic acid, Oxalic acid, Benzoic acid, Copper sulphate as well as Potassium sorbate at concentration of 30 and 45 mM, completely inhibited the growth of M .phaseolinaand R. solani. Significant reductions in disease severity were noticed under green house and field conditions when abovementioned treatments were applied under artificial and natural infection