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Apple and pear fire blight

Scientific Name
Erwinia amylovora
Scientific Author
(Burrill 1882) Winslow, Broadhurst, Buchanan, Krumwiede, Rogers & Smith 1920

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Diagnostic Images

Host Symptoms
Symptoms on blossom (left) and pear fruit (right) (copyright, for use contact [email protected]).
Marco Scortichini Istituto Sperimentale Per La Frutticoltura, Roma, Italy
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Diagnostic Images (3)
Diagnostic Notes

E. amylovora is systemically distributed in plants and can survive as an endophyte and an epiphyte. Symptoms develop following the seasonal growth of the host plant. First water-soaked lesions can occur on flowers, peduncles, immature fruits and twigs. Leaves wilt and shrivel. Later, the infected organs turn brown to black, as though burned by fire, oozing droplets of bacterial exudates under favourable weather and usually remaining attached to the tree for some time. The terminal shoot becomes shepherd's crook-shaped. The bacteria move down from infected twigs into main branches causing canker and cracks on the bark. Cankers can occur on the trunk and rootstock. When the bacteria infect highly susceptible rootstocks, the canopy can remain symptomless. The disease can kill branches and the entire tree (Lopez et al. 2004, Crop protection compendium 2005, Steiner et al. 2006). A detailed description of the development of the symptoms is given by Steiner et al. (2006) and van der Zwet & Beer (1995).

The bacteria:

Gram-negative, rod-shaped, motile, facultative anaerobic, 0.5-1 x 1-3 µm, with peritrichous flagella. A detailed description of Erwinia amylovora is given by Bradbury (1986). Comprehensive details of the identification of E. amylovora using multiple techniques can be found in López et al. (2004). PCR-based identification methods for this pathogen have been developed (Guilford et al. 1996, Llop et al. 2000, Taylor et al. 2001, Salm & Geider 2004).
More Information
Specimen Contact
Dr Jose R. Liberato
Liberato JR & Scortichini M
03/08/2006 06:56 AEST
Last Updated
28/07/2016 09:04 AEST
Liberato JR & Scortichini M (2006) Apple and pear fire blight (Erwinia amylovora ) Updated on 7/28/2016 9:04:53 AM Available online: PaDIL -
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Free for use under the Creative Commons Attribution 3.0 Australia License