THE CONTROL OF BOTRYTIS-CINEREA AND RHIZOCTONIA-SOLANI ON LETTUCE USING ELICITORS EXTRACTED FROM YEAST-CELL WALLS

Water soluble yeast cell wall extracts induced phytoalexin accumulation on soybean cotyledons and protected lettuce against Botryis cinerea and Rhizoctonia solani infection. On detached leaves of cv. 'Little Gem', B. cinerea infection was reduced by up to 90 % whilst in the glasshouse B. cinerea and R. solani infection were reduced by approximately 70 % on cvs. 'Little Gem' and 'Patricia', and by approximately 50 % on cv. 'Berlo'. Extracts applied with the non-ionic wetter Agral controlled disease more effectively in the glasshouse than those with the acidic surfactant LI-700 thus demonstrating the importance of formulation. The extracts do not exhibit direct antifungal activity and there were no phytotoxic or otherwise detrimental effects observed following application of any of the formulations on any of the lettuce cultivars.