POTENTIAL OF YEASTS FOR YAM LEAF-BLIGHT B IOCONTROL

Ten yeast isolates were studied as potential agents for biocontrol of yam leaf spot, caused by Curvularia eragrostidis. Under greenhouse con ditions most of the isolates showed good disease control. Application of the antagonists simultaneously as C. eragrostidis inoculation gave the best results, when the LD-18 isolate (Rhodotorula glutinis) reduci ng disease severity reduction better than mancozeb. The efficiency of the LD-18 was reduced by adding peptone or dextrose to eel suspensions . Ultrasctrutural analysis of the interactions between the C. eragrost idis and LD-18 on yam leaf surface showed conidial germination 6 hours after inoculation, and adhesion of yeast cells to the germination tub es. In laboratory tests, the production of non-volatile extracellular metabolites by LD-19 could not be detected.