الفهرس 
New approaches for controlling some soil borne fungal diseases of Soybean in Egypt
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Abstract
The objectives of this study aimed to isolate and identify the causal organisms of the major soil borne fungal disease of soybean plants. Many approaches of control measures were evaluated in control of soybean damping-off and root rot pathogens under laboratory, green house and field condition. The obtained results proved that Macrophomina phaseolina ,Rhizoctonia solani , Fusarium solani and Sclerotium rolfsii were responsible for damping-off and root rot diseases on soybean plants, these fungi are wide spread all over in all surveyed five governorates in Egypt , as the disease incidance and severity reached to 19.3 % and 10.5 %. In vitro Trichodirma harzianum, T.viride, Bacillus subtilis and Pseudomonas fluorescens were highly antagonistic agents against damping-off and root rot pathogens, when these bio-agents were used as seed bio priming technique. They resulted in high decrease in damping-off and root rot disease incidence compared with seed coating with such bio agents. Essential oils i.e., citral (0.25 %) and thyme oil ,lemongrass oil and eucalyptus oil at 1 % concentration as well as chitosan (6%),sorbic acid, benzoic acid, salicylic acid at 0.1 % caused complete inhibition of linear growth, sporulation and sclerotial formation of damping-off and root rot pathogens in vitro. Integrative treatments of chitosan and essential oil and induces resistance chemical were most effective thane signal treatment. Greenhouse results revealed that seed bio priming, essential oils, induces resistance chemical treatment and chitosan suppressed the incidence of damping-off and root rot diseases on soybean plants sown in artificially infested soil by the damping-off and root rot pathogens compared with the control. Seed bio priming, seed dressing with Rizolex{u2013}T. combined treatments of chitosan and citral oil, potassium sorbate had superior significant effect on reducing damping-off and root rot diseases and improving the vegetative growth parameters of soybean plants. Such treatments reduced the incidence of damping-off and root rot diseases by more than 69.7 and 62.8 % at damping-off and root rot diseases, respectively