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United States Department of Agriculture

Agricultural Research Service


item Polashock, James
item Oudemans, Peter

Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 7/24/2004
Publication Date: 8/13/2004
Citation: Polashock, J.J., Oudemans, P.V. 2004. Molecular identification of the 'black shadow' pathogen of blueberry. Meeting Abstract.

Interpretive Summary:

Technical Abstract: 'Black Shadow' is an emerging disease on highbush blueberries grown in New Jersey. The disease appears as black mycelium on the surface of 1-2 year old stems. Affected bushes generally decline and have reduced yields. In culture, isolates of the fungus grow yeast-like, as single cells that proliferate by budding. Observations based on morphology and growth habit led to preliminary identification of the causal agent as Aureobasidium pullulans. This conclusion was supported by an abstract published several years ago describing A. pullulans as pathogenic on blueberry. To verify identification, the nuclear rDNA region containing ITS2, 5.8S rDNA and ITS 4 was amplified from several isolates of the fungus, cloned and sequenced. Sequence similarity searches using BLAST suggested the isolated species was Rhizosphaera kalkoffii. Interestingly, this species of fungus has only been reported as a pathogen of conifers where it causes a disease known as 'needle cast'.

Last Modified: 06/26/2017
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