Premium
Effect of inoculum density, stage of plant growth and dew period on the incidence of black point caused by Alternaria alternata in durum wheat
Author(s) -
SOUTHWELL R. J.,
BROWN J. F.,
WONG P. T. W.
Publication year - 1980
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.1744-7348.1980.tb04765.x
Subject(s) - alternaria alternata , biology , anthesis , dew , incubation period , inoculation , incidence (geometry) , dew point , agronomy , horticulture , incubation , cultivar , mathematics , biochemistry , physics , meteorology , condensation , thermodynamics , geometry
SUMMARY Glasshouse studies showed that the incidence of black point caused by Alternaria alternata in durum wheat was positively correlated with both the density of the inoculum and the growth stage of the wheat plants at the time of inoculation. A curvilinear relationship of the form Y = a + log X was found between inoculum density and disease incidence. The incidence of black point was linearly related to the stage of plant growth, between anthesis and the late milk stages of development, at the time of inoculation. A better relationship between growth stage and disease incidence was found when plant growth was expressed as days after anthesis than when the Romig scale was used ( R 2 = 0.30 and 0.24 respectively). A threshold dew period of 3–6 h was required for black point symptoms to develop. The incidence of black point increased with increasing duration of the dew period until maximum disease incidence occurred after exposure to a dew period of 48 h.