.Evaluation of Non-Pathogenic Pythium spp. as Biocontrol Agents Against Injury of Young Plants Induced by Decomposition of Green Manure

RESEARCH REPORTS FROM INSTITUTE FOR AGRO-MICROBIOLOGY, Vol. 4, 2000 p.45-59
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ORIGINAL ARTICLE

4.Evaluation of Non-Pathogenic Pythium spp. as Biocontrol Agents Against Injury of Young Plants Induced by Decomposition of Green Manure

－Suppressiveness of Pythium oligandrum to Damping-off of Cucumber Induced by Decomposition of Green Manure－

Motoaki Tojo and Kayoko Nakayama(College of Agriculture, Osaka Prefecture University)

Pythium oligandrum was tested for suppression of damping-off of cucumber induced by the decomposition of green manure and for enhancement of decomposition of green manure in soil. Seedling stand of cucumber was increased when the soil was infested with P. oligandrum at 1000 CFU g-1-dry soil with incorporation of oat and red clover green manure at 1-2% (w/w) into the soil. P. oligandrum was recovered from soil at 50-200 CFU g-1 -dry soil until 30 days after incorporation of the green manure. Suppressiveness of P. oligandrum to P. ultimum and P. spinosum isolated as main causal agents of damping-off of the plant was certified by their inoculation test in greenhouse experiment. Carbon mineralization from green manure decomposing in autoclaved soil and weight reduction of green manure decomposing in field condition were not influenced by inoculation of P. oligandrum.

Keywords: biocontrol agents, decomposition of green manure, non-pathogenic Pythium spp., pathogenic Pythium spp., Pythium oligandrum