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Black Spot and Rain: A Markov Chain Model for Appleby, New Zealand
Author(s) -
RICHARDS KATRINA
Publication year - 2002
Publication title -
new zealand geographer
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.335
H-Index - 25
eISSN - 1745-7939
pISSN - 0028-8144
DOI - 10.1111/j.1745-7939.2002.tb01636.x
Subject(s) - black spot , markov chain , distribution (mathematics) , geography , demography , environmental science , horticulture , biology , statistics , mathematics , sociology , mathematical analysis
ABSTRACT Black spot (Venturia inaequalis) is a serious fungal disease of apples associated with rain. Control is by use of agrichemicals, but infection still occurs. A first‐order Markov chain probability model was applied to the distribution of spring wet spells for Appleby, for Sep–Dec, 1982–1990. Comparison with risk periods for primary black spot infection showed that, while 1‐day wet spells were the most frequent (41% probability of occurrence), the most frequent occurrence of risk periods was in association with 2‐day wet spells. Long wet spells (up to 18 days) were almost always associated with risk periods, but were infrequent.