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Powdery mildew of tobacco ( Erysiphe cichoracearum DC.)
Author(s) -
COLE J. S.
Publication year - 1964
Publication title -
annals of applied biology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.677
H-Index - 80
eISSN - 1744-7348
pISSN - 0003-4746
DOI - 10.1111/j.1744-7348.1964.tb01194.x
Subject(s) - powdery mildew , potassium , biology , sugar , phosphorus , nutrient , nitrogen , mildew , horticulture , reducing sugar , agronomy , botany , food science , chemistry , organic chemistry , ecology
In water culture experiments, tobacco plants of Hicks variety were supplied with factorial combinations of high and low concentrations of nitrogen, phosphorus and potassium. Incidence of powdery mildew and growth and chemical composition of infected and healthy plants were compared. There was more disease when all elements were supplied at the higher of two concentrations, but the increase in infection was less than the increase in growth. Plants grown in media containing a low ratio of potassium to nitrogen produced the least susceptible leaves; their disease indices were up to 30 times less than those of plants that received the full nutrient treatment. Potassium‐deficient leaves had thinner cell walls, larger water content, smaller sugar and potassium contents, and greater amino nitrogen and magnesium contents, compared with those of plants grown in any of the other media. The possible relation between these characteristics and susceptibility to Erysiphe cichoracearum DC. are discussed.