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Coincidence of maximum severity of powdery mildew on grape leaves and the carbohydrate sink-to-source transition


Merry, AM and Evans, KJ and Corkrey, R and Wilson, SJ, Coincidence of maximum severity of powdery mildew on grape leaves and the carbohydrate sink-to-source transition, Plant Pathology, 62, (4) pp. 842-850. ISSN 0032-0862 (2013) [Refereed Article]

Copyright Statement

Copyright 2012 University of Tasmania

DOI: doi:10.1111/j.1365-3059.2012.02691.x


Grapevine leaves infected with powdery mildew are a source of inoculum for fruit infection. Leaves emerging on a single primary shoot of Vitis vinifera cv. Cabernet Sauvignon were exposed to average glasshouse temperatures of 18°C (023 leaves emerging/day) or 25°C (054 leaves emerging/day). All leaves on 8–10 shoots with approximately 20 leaves each were inoculated with Erysiphe necator conidia to assess disease severity after 14 days in the 25°C glasshouse. Two photosynthetic ‘source’ leaves per shoot on the remaining 8–10 shoots were treated with 14CO2 to identify, by autoradiography, the leaf position completing the carbohydrate sink-to-source transition. There was a clear association between the mean modal leaf position for maximum severity of powdery mildew (position 37 for 18°C; position 44 for 25°C) and the mean position of the leaf completing the sink-to-source transition (position 38 for 18°C; position 47 for 25°C). The mean modal leaf position for the maximum percentage of conidia germinating to form secondary hyphae was 42 for additional plants grown in the 25°C glasshouse. A higher rate of leaf emergence resulted in a greater proportion of diseased leaves per shoot. A Bayesian model, consisting of component models for disease severity and leaf ontogenic resistance, had parameters representing the rate and magnitude of pathogen colonization that differed for shoots developing in different preinoculation environments. The results support the hypothesis that the population of leaves in a vineyard

Item Details

Item Type:Refereed Article
Keywords:biotroph, host growth, host–pathogen interaction, Uncinula necator, viticulture
Research Division:Agricultural, Veterinary and Food Sciences
Research Group:Horticultural production
Research Field:Oenology and viticulture
Objective Division:Plant Production and Plant Primary Products
Objective Group:Horticultural crops
Objective Field:Table grapes
UTAS Author:Merry, AM (Dr Angela Merry)
UTAS Author:Evans, KJ (Associate Professor Katherine Evans)
UTAS Author:Corkrey, R (Dr Ross Corkrey)
UTAS Author:Wilson, SJ (Dr Stephen Wilson)
ID Code:78707
Year Published:2013 (online first 2012)
Web of Science® Times Cited:10
Deposited By:Agricultural Science
Deposited On:2012-07-22
Last Modified:2017-11-06

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