الفهرس | Only 14 pages are availabe for public view |
Abstract In this study, a survey of the disease was carried out along the Northern Western Coast (NWC) of Egypt under rainfed conditions. The survey revealed that high percentage of disease incidence was recorded at Abo-Lahow followed by Abo-Atiah and Abo-Lawh. The lowest percentage of disease incidence was recorded at El-Hafian. The aim pathogrns caused wheat root-rot in NWC were Heminthosporium sativum, Fusarium graminearum, F.moniliforma and Rhizoctonia solani. H.Sativum was the most frequency isolated fungus, while the lowest frequent one was F. monilofprme. Pathogenicity tests provide that the most virulence fungus was F. graminearumfollowed by H.sativum and R. sativum, while the least virulence one was F. moniliforme thus fungus was omitted. Synergistic effect was noticed when the most virulence fungi were mixed and percentage of disease incidence was increased. The isolation of microorganisms from rhizosphere of healthy wheat plants was carried out to select the most antagonistic one to use in biological control.. Trichoderma harzainum (T.S), T. hamatum (T.H.), Streptomyces giesus and Bacillus subtilis were the most frequent isolated microorganisms. According to in vitro testing, T. harzianum gave highest significant reduction in mycelia growth of the pathogenic fungi followed by T.hamatum. Antagonistic fungi (T.S. and T.H.) completely inhibited sclerotial formation of R. solani. The antagonism between the pathogen and the bioagent could be affected by the type of media. In this work, slide technique was used to study effect of bioagents on mycelium of pathogenic fungi. T. harzianum caused malformation in the mycelium of pathogenic fungi and grow over the host mycelium followed by more close contact interaction and invade it. B. subtilis also caused malformation and decaying for pathogenic mycelia. |