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Field and laboratory studies of the effect of urea on ascospore production of Venturia inaequalis (Cke.) Wint
Author(s) -
BURCHILL R. T.
Publication year - 1968
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.1744-7348.1968.tb02825.x
Subject(s) - venturia inaequalis , biology , ascospore , urea , overwintering , abscission , fungus , botany , horticulture , agronomy , spore , fungicide , biochemistry
SUMMARY Applications of urea after harvest but before leaf‐fall restricted perithecial production by Venturia inaequalis. Immersion of detached leaves in urea appeared to be the most effective method of preventing perithecial formation, although spraying attached leaves was equally effective when leaf abscission occurred within a week of treatment. A high nitrogen content within the leaf was one of the major factors contributing to suppression. Urea‐treated leaves decomposed rapidly, thus destroying the overwintering substrate for the fungus. When apple plants (clone M. 111) were sprayed in autumn with 5 % urea, followed by a second (pre‐bud‐burst) application at 2 %, ascospore production in the spring was suppressed. The second treatment appeared to prevent the release of ascospores from mature perithecia.