|TRIGIANO, ROBERT - University Of Tennessee|
|Rinehart, Timothy - Tim|
|DEE, MARY - University Of Tennessee|
|WADL, PHIL - University Of Tennessee|
|POPLAWSKI, LAURA - University Of Tennessee|
|OWNLEY, BONNIE - University Of Tennessee|
Submitted to: Plant Disease
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/12/2013
Publication Date: 5/15/2014
Citation: Trigiano, R.N., Rinehart, T.A., Dee, M.E., Wadl, P.A., Poplawski, L., Ownley, B.H. 2014. First Report of Aerial Blight of Ruth’s Golden Aster (Pityopsis ruthii) caused by Rhizoctonia solani in the United States. Plant Disease. 98(6):855.
Interpretive Summary: To our knowledge, this is the first report of Rhizoctonia solani infecting Ruth's golden aster. We are not aware of the disease occurring in wild populations of the plant, but may impact plants grown in the landscape or greenhouse. To verify the pathogen, plants were grown in a greenhouse and covered with a plastic dome to maintain high humidity. They were then inoculated with Rhizoctonia solani strains collected from original infected plants. After two weeks, six of the seven inoculated plants exhibited the same aerial blight symptoms as did the original infected plants from the field; none of the control plants developed disease symptoms. Colony morphology and hyphal characteristics as well as the sequence for the ITS region of rDNA from the reisolated fungus were identical to the original isolate.
Technical Abstract: Ruth's golden aster (Pityopsis ruthii) is an endangered, herbaceous perennial that occurs only at a few sites along small reaches of the Hiwassee and Ocoee rivers in Polk County, Tennessee. This species has ornamental potential. In 2012, we vegetatively propagated various genotypes and established plantings in a landscape at Poplarville, Mississippi. In June and July of 2013, during periods of hot and humid weather, several well-established plants exhibited black or brown necrotic aerial blight symptoms, stems and leaves were also desiccated. Blighted leaf samples were surface-sterilized, rinsed in sterile water, air-dried, and plated on 2% water agar. Rhizoctonia species was identified based on hyphal morphology and cultures were maintained on potato dextrose agar.