ERWINIA-SALICIS IN CRICKET BAT WILLOWS - PHENOLIC CONSTITUENTS IN HEALTHY AND DISEASED WOOD

The content of total polyphenols in Erwinia salicis infected cricket bat willow wood (Salix alba var. caerulea) with watermark symptoms is twice that of healthy wood. There is a similar increase in total leucoanthocyanins. The increase in phenolic compounds during disease is quantitative not qualitative. Cyanidin-type compounds, catechin and salicin, increase, whereas saligenin and phloroglucinol decrease in diseased tissue. A major, unidentified phenolic component of healthy wood markedly decreases on infection. Colourless compounds (or as yet unknown physical mechanisms) are likely to be involved in the resistance of willow wood to E. salicis infection rather than the slowly produced watermark (blackening) symptom itself. © 1978.