First report of powdery mildew on Ruth's golden aster (Pityopsis ruthii) caused by Golovinomyces cichoracearum (Erysiphe cichoracearum).

摘要

Ruth's golden aster (Pityopsis ruthii, Asteraceae) 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, USA. As part of a planned restoration program, Ruth's golden aster has been micropropagated in vitro and acclimatized to greenhouse conditions. In February 2011, several established plants in a greenhouse in Knoxville exhibited signs and symptoms of powdery mildew including growth of white mycelium and conidiophores on the adaxial surface of leaves and slight curling upward of leaf margins. Based on morphological characteristics, sequence analysis of ITS and pathogenicity test, the causal agent was identified as G. cichoracearum (E. cichoracearum). This is thought to be the first report of G. cichoracearum infecting Ruth's golden aster.Digital Object Identifier http://dx.doi.org/10.1094/PDIS-04-11-0289