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The repression and stimulation of growth of Erysiphe sp. on Rhododendron by fungicidal compounds
Author(s) -
KENYON D. M.,
DIXON G. R.,
HELFER S.
Publication year - 1997
Publication title -
plant pathology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.928
H-Index - 85
eISSN - 1365-3059
pISSN - 0032-0862
DOI - 10.1046/j.1365-3059.1997.d01-25.x
Subject(s) - fungicide , powdery mildew , biology , spore , botany , horticulture , propiconazole , ericaceae , pathogen , microbiology and biotechnology
Erysiphe sp. is a causal agent of powdery mildew on Rhododendron . A novel in vivo method permitting the screening of fungicides on woody plants is described. Eight fungicides were evaluated for activity against Erysiphe sp. using Rhododendron ponticum microplantlets grown in vitro. Pathogen development changed with both the type of fungicidal compound and the concentrations applied. The most active materials were fenpropidin and penconazole, which showed high activity at the lowest concentrations. Six of the compounds performed more effectively than a mixture of bupirimate + triforine (Nimrod T), the standard recommendation for control of this pathogen on Rhododendron . All fungicides affected the sporulation of Erysiphe sp., with propiconazole, pyrazophos and triadimenol causing a significant increase in sporulation at the lowest concentrations. At higher concentrations, sporulation was significantly reduced by all treatments. No phytotoxic effects were detected with any fungicide at any concentration. The growth of plantlets in most treatments showed no significant difference from the untreated controls. The results of the study are discussed in relation to strategies for control and the epidemiology of Erysiphe sp. infecting Rhododendron .