|Ting, MO -|
Submitted to: Phytopathology Supplement; APSnet (Plant Pathology Online)
Publication Type: Abstract Only
Publication Acceptance Date: May 17, 2012
Publication Date: July 1, 2012
Citation: Hanson, L.E., Ting, M., Goodwill, T.R. 2012. Variability in Phoma species affecting sugar beet. Phytopathology Supplement; APSnet (Plant Pathology Online). DOI.org/10.1094/PHYTO-102-7-S4.50. Technical Abstract: Phoma betae can cause damage to sugar beet (Beta vulgaris) at multiple growth stages. It has historically been an important seedling disease, but this is largely managed by ensuring clean seed for planting. The pathogen also can cause a root rot, a leaf spot, and rotting of beets during storage. In the United States, the only pathogenic Phoma associated with beets has been Phoma betae. In Eastern Europe, some additional Phoma species have been reported to cause symptoms on sugar beet. Our aim was to investigate variability in Phoma isolates from sugar beet in the United States to determine whether there might be more than one species causing symptoms on beet. Phoma isolates had been collected as part of ongoing surveys for seedling diseases and root rot, and additional samples were collected from leaf spots. Isolates were examined for morphological characters on malt extract agar and oatmeal agar and a portion of the ITS region was sequenced for comparison. Of 14 isolates identified as Phoma by both morphological and molecular testing, six showed highest identity with P. betae while the remaining isolates showed highest identity with Phoma species other than P. betae. Leaf spots were observed on sugar beet treated with either Phoma betae or other Phoma isolates and pathogenicity screening is continuing.