الفهرس 
Improvement of bean resistance to damping-off and root-rot diseases
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Abstract
Bean (Phaseolus vulgaris L.) is a very important legume crop in Egypt for local consumption and exportation. Many soil-borne pathogenic fungi can infect bean roots; from those Rhizoctonia solani, Fusarium solani and Macrophomina phaseolina are able to cause damping-off , root-rot and charcoal-rot, ashy stem blight diseases . Ninety nine fungal isolates representing six fungal species were isolated from bean diseased roots and stems showing the typical symptoms of damping-off, root rot, wilt and stem rot diseases. The isolated fungi were purified and identified as Aspergillus niger, Fusarium oxysporum, F. solani , Macrophomina phaseolina , Pythium debaryanum and Rhizoctonia solani. All the isolated fungi, except A. niger were pathogenic and caused different degrees of damping-off when used to test their pathogenic potentialities using Nebraska bean cv. Data indicated clear variations in respect to the ability of the tested fungi to attack bean. Severe symptoms were appeared on plants grown in soil infested with each of R. solani, F.solani, M. phaseolina.In this study, blue-green algae were used as bioagents against the pathogenic fungi, we used the filtrates of the three blue green algal species, i.e. Spirulina platensis, Nostoc muscorum, Anabaena flos-aquae in managing R. solani , F. solani and M. phaseolina; the causal of root - rots in vitro and in the greenhouse. It was observed that the tested concentrations of the three cynaobacterial filtrates resulted in significant inhibitory effect to the fungal growth of the three fungi. The reduction in the linear growth was increased gradually by increasing the concentration of the filtrate. In addition, the tested cyanobacteria significantly reduced the infection by the tested fungi and improved crop parameters of bean plants