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 accumulatio n on soybean cotyledons and protected lettuce against Botryis cinerea and Rhizoctonia solani infection. On detached leaves of cv. 'Little Ge m', B. cinerea infection was reduced by up to 90 % whilst in the glass house B. cinerea and R. solani infection were reduced by approximately 70 % on cvs. 'Little Gem' and 'Patricia', and by approximately 50 % o n cv. 'Berlo'. Extracts applied with the non-ionic wetter Agral contro lled disease more effectively in the glasshouse than those with the ac idic surfactant LI-700 thus demonstrating the importance of formulatio n. The extracts do not exhibit direct antifungal activity and there we re no phytotoxic or otherwise detrimental effects observed following a pplication of any of the formulations on any of the lettuce cultivars.