TITLE	Influence of bean seedling root exudates on the rhizosphere colonization by Trichoderma lignorum for the control of Rhizoctonia solani
AUTHOR	N.H. Aziz Microbiology Department, National Center for Radiation Research and Technology, P.O. Box 29 Nasr City, Cairo, Egypt M.Z. El-Fouly Microbiology Department, National Center for Radiation Research and Technology, P.O. Box 29 Nasr City, Cairo, Egypt A.A. El-Essawy Botany Department, Faculty of Science, Zagazig University Zagazig, Egypt M.A. Khalaf Microbiology Department, National Center for Radiation Research and Technology, P.O. Box 29 Nasr City, Cairo, Egypt
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ABSTRACT	Application of Trichoderma lignorum as a seed coating (8 × 106 conidia/seed) or wheat bran preparation (1 × 106 cfu/g) at a rate of 20 g/kg soil, greatly reduced the number of bean seeds infested by Rhizoctonia solani, and the percentage of healthy seeds reached 92%. Germination of conidia of Rhizoctonia solani in bean rhizosphere soil was inhibited after soil or seed application with Trichoderma lignorum. Bean seedling exudate increased the mycelial growth rate of Rhizoctonia solani and Trichoderma lignorum in vitro. Under greenhouse conditions, the addition of germinating bean seed exudate to soil infested with Rhizoctonia solani and planted with bean, reduced the disease control capability of the antagonist. Plants grown from seeds treated with Trichoderma lignorum had roots with lower levels of Rhizoctonia solani in their rhizosphere than the roots of untreated seeds. Trichoderma had little effect on the survival of Rhizoctonia solani in non-rhizosphere soil. However, application of Trichoderma lignorum as a wheat-bran preparation, conidial suspension or seed coating reduced the pathogen counts in the rhizosphere soil of beans.
KEYWORD	Biocontrol; Rhizoctonia solani antagonism; Soilborne plant pathogens;
ARTICLE INFO	Botanical Bulletin of Academia Sinica, Volume 38 Number 1 January 1997, page 33-39, 7 pages
PUBLISHER	Institute of Plant and Microbial Biology, Academia Sinica, Taipei, Taiwan, Republic of China