الفهرس 
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Abstract
In this study, 4 fungi i.e.: F. moniliforme, F. solani, R. solani and S. bataticola obtained from wilted roots of sugar beet plants grown in fields at different areas in Dakahlia Governorate were purified and identified based on the identification keys. The pathogenicity tests revealed that all tested fungi have potential to attack sugar beet roots (Beta vulgaris L.) cv. Tenor and cause damping-off, root rot, wilt and a reduction in the number of healthy plants.In vitro studies revealed that the antioxidants: salicylic acid (SA), Tartaric acid, GAWDA® formulation and the antagonistic fungi i.e.: T. harzianum and T. viride presented inhibitory effect on the sugar beet root rot and wilt pathogens.Since the hazards of using pesticides for plant disease control, a modern alternative was applied to reduece the effect of the root diseases caused by both, F. moniliforme, F. solani, R. solani and S. bataticola. In this study, application of compost, antioxidant i.e.: Salicylic acid, Tartaric acid, GAWDA® formulation and antagonistic fungi i.e.: T. harzianum and T. viride or their combinations were applied as they accelerate the resistance rate in sugar beet plants against the above soil-borne fungi. In vitro study, presented salicylic acid at concentrations of 2, 4, 6, 8 mM, tartaric acid at (5, 10, 15, 20 mM) and GAWDA® formulation at (1, 2, 3 and 4 gl-1) as effective green chemicals to reduce the linear growth of F. moniliforme, F. solani, R. solani and S. bataticola isolated from sugar beet roots. It was also noticed that the reduction in the linear growth was correlated to the increase in concentration of the tested antioxidants.In greenhouse studies, the triple formulation consists of compost, Trichoderma and antioxidants significantly reduced the percentage of damping-off syndrome of sugar beet infected with F. moniliforme, F. solani, R. solani and S. bataticola. Precisely the combinations of (compost, salicylic acid and T. viride or T. harzianum) or (compost, Tartaric acid and T. harzianum or T. viride) were highly effective on reducing the incidence of damping-off. Also, the effect of the triple formulation on content of the photosynthetic pigments and total phenols were obvious. Compost, Trichoderma and antioxidants solely or in combination compost, GAWDA at 4 mM significantly increased the contents of chlorophyll A, chlorophyll B. Total chlorophyll, carotenoid and the total phenols as well as growth parameters i.e.: plant height, shoot length, root length, leave numbers, plant weight, shoot weight, root diameter and root weight of the 120, 150 and 200 days old plants were significantly increased.Also, the impact of using compost, Trichoderma and antioxidants solely or in combination on the content of the total sugar and TSS in sugar beet plants infected with the above fungi revealed that the compost, GAWDA formulation of 4 mM and T. harzianum significantly increased the total sugar and TSS.In field trials, the triple formulation consists of compost, Trichoderma and antioxidants significantly reduced the percentage of damping-off syndrome of plant grown under natural infection. While the combinations of (compost, salicylic acid and T. viride or T. harzianum) or (compost, Tartaric acid and T. harzianum or T. viride) were highly effective on reducing the incidence of damping-off. Also, applying the triple formulation presented their positive effects on the content of the photosynthetic pigments and total phenols as well as growth parameters.The result presented here addresses green chemicals as promising friendly materials for producing sugar beet roots with higher content of sugar (38.5% increase) and increase the yield by 115% the recommended method is to soak the seeds in water solution of formulation of GAWDA at 4 mM and T. harzianum used for treating sugar beet seeds before sawing in soil supplemented with compost at a rate of (2 ton/fed.).