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Epidemiology and status of walnut blight in Australia
Citation
Lang, MD and Evans, KJ, Epidemiology and status of walnut blight in Australia, Journal of Plant Pathology, 92, (1) pp. S49-S55. ISSN 1125-4653 (2010) [Refereed Article]
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Copyright Statement
Copyright © 2010 Italian Phytopathological Society
Official URL: http://www.sipav.org/main/jpp/jol/jol_sep_10.htm
Abstract
Walnut blight, caused by Xanthomonas arboricola pv.
juglandis, is present in all walnut growing regions of
Australia, and has been responsible for significant losses
of walnut fruits in Tasmania. The pathogen has been
isolated from buds just prior to bud-burst in Tasmania,
and disease symptoms on fruit of introduced cultivars of
Juglans regia are similar to those observed in other
growing regions of the world. This review focuses on
the approach taken to model disease progression and
describes how these models can help interpret the efficacy
of spray programs, identify key factors influencing
epidemic development and build tools for supporting
decisions about spray timing. Considerable differences
in the temporal progression of disease incidence on cvs
Franquette and Vina fruits were found between three
growing years in Tasmania, with incidences near harvest
ranging from 19 to 100%. Final disease incidence was
correlated positively to the quantity of rainfall during
the first 4 weeks after bud-burst. Disease incidence was
then used for modelling these epidemics because incidence
on half full-size diameter fruit accounted for 97%
of the variance in yield of Vina walnuts. The monomolecular
growth model with K = 1 obtained a good fit for
the ten epidemics analysed. In a dry year, two sprays of
copper-based biocide (300 g/kg of copper hydroxide
formulated with 150 g/kg mancozeb) applied one week
apart from 5% terminal bud-burst provided commercially
acceptable control whereas up to nine sprays in a
wetter year failed to control this disease. It was concluded
that copper-based biocides could be timed strategically
and according to the slow rate of disease development
in drier years.
Item Details
| Item Type: | Refereed Article |
|---|---|
| Keywords: | asymptote, bacterial plant pathogen, crop |
| Research Division: | Biological Sciences |
| Research Group: | Plant Biology |
| Research Field: | Plant Pathology |
| Objective Division: | Plant Production and Plant Primary Products |
| Objective Group: | Horticultural Crops |
| Objective Field: | Tree Nuts (excl. Almonds and Macadamias) |
| Author: | Lang, MD (Mr Michael Lang) |
| Author: | Evans, KJ (Dr Katherine Evans) |
| ID Code: | 63142 |
| Year Published: | 2010 |
| Web of Science® Times Cited: | 1 |
| Deposited By: | Agricultural Science |
| Deposited On: | 2010-04-15 |
| Last Modified: | 2012-10-18 |
| Downloads: | 16 View Download Statistics |
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