May
2007
, Volume
91
, Number
5
Pages
616
-
623
Authors
T. A.
Rinehart
and
W. E.
Copes
,
United States Department of Agriculture, Agricultural Research Service, Thad Cochran Southern Horticultural Laboratory, 810 Highway 26 West, Poplarville, MS 39470
; and
T.
Toda
and
M. A.
Cubeta
,
North Carolina State University, Department of Plant Pathology, Center for Integrated Fungal Research, 225 Partners III, Raleigh, NC 27695-7567
Affiliations
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RelatedArticle
Accepted for publication 11 December 2006.
Abstract
ABSTRACT
Web blight on containerized azalea is an annual problem for commercial nurseries during summer months in the southern United States. Losses to web blight are associated with the cost of fungicide applications, delayed marketing of diseased plants, and plant death. Two hundred and eleven isolates of binucleate Rhizoctonia were recovered from azalea leaves with web blight symptoms from two nurseries in Mississippi and Alabama over 3 years. The internal transcribed spacer region (ITS) of the ribosomal DNA (rDNA) was sequenced from all isolates to determine genetic identity. A single anastomosis group (AG) of binucleate Rhizoctonia represented 92% of the samples collected from infected leaves. Genetic data and hyphal fusion experiments confirmed that these isolates belong to AG-U, which was recently identified from root and stem infections on miniature rose in Japan. Isolates of binucleate Rhizoctonia belonging to anastomosis groups AG-R, CAG-7 (=AG-S), and AG-G were also identified in the sample in low frequency. This is the first report of the occurrence of binucleate Rhizoctonia AG-U in the United States.
JnArticleKeywords
Additional keywords:
Ceratobasidium,
rhododendron
Page Content
ArticleCopyright
The American Phytopathological Society, 2007