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Camellia flower blight

Scientific Name
Ciborinia camelliae
Scientific Author
L.M. Kohn
Taxonomy
Ascomycetes, Sclerotiniaceae

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Diagnostic Images

Pathogen
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Caption
A group of fresh apothecia (from two germinated sclerotia) (copyright P.G. Long, for use contact P.G.Long@massey.ac.nz).
Source
Dr Peter Long Massey University
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Diagnostic Images (23)
Diagnostic Notes

Symptoms: The fungus infects flowers (and sometimes 1-2 mm into the stem from an infected flower) of the genus Camellia. Small (1-3 mm) pale brown spots appear 1-2 days after infection. They rapidly spread on very susceptible varieties and the complete petal may become brown within three days.  Further spread is from the base of one petal to another. The lesions are pale brown usually with an irregular shape and often with a network of darker brown veins. Most flowers fall to the ground and sclerotia develop at the base of the petals after a few weeks. They may be small (2-4 mm diam.) isolated sclerotia or compound sclerotia up to 30 mm diam. formed by the fusion of large sclerotia around the base of the petals. Compound sclerotia do not develop on varieties with flowers that shatter when they fall and even small sclerotia may fail to form on many individual petals. In wet conditions, patches of black microconidia can be found.

 

Flower blights caused by other pathogens do not have the grey-white felty mycelial ring under the sepals.  Penicillium spp. May form a blue-green ring of sporulating mycelium and the diseased tissue is usually dark brown. Blight caused by Botrytis cinerea lacks the mycelial ring and there is usually sporulation in between the stamens and petals. Pestalotia sp. cause a dark brown rot and black sporulation develops on the flower stalk. Frost damage usually causes a browning of the petal margins, especially when the flower is at the unfurling stage.

 

The sclerotia do not germinate in the same season they are formed but most will probably germinate the next spring and a few may germinate over the next few growing seasons.

 

The apothecia develop from the germinated sclerotia from mid-July to November in New Zealand and the corresponding spring months in the northern hemisphere. Each apothecium may release spores for up to 2 weeks but most are released in the first 7 days. As apothecia age, they lose their cupped shape, become a darker brown and more leathery in texture.

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More Information
Specimen Contact
Dr Peter Long (Institute of Natural Resources, Massey University, Palmerston North, New Zealand)
Author
Long P.G.
Created
08/06/2006 11:17 AEST
Last Updated
21/10/2011 09:31 AEST
Citation
Long P.G. (2006) Camellia flower blight (Ciborinia camelliae ) Updated on 10/21/2011 9:31:16 AM Available online: PaDIL - http://www.padil.gov.au.
Image Use
Free for use under the Creative Commons Attribution 3.0 Australia License

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