Two new records of powdery mildews with their effectiveness on three ornamentals in Turkey

Abstract

In this study, two new species of powdery mildews together with disease severities measured at four different growing stages were identified on three ornamental species in the Ažanliurfa district of Turkey. Observations and measurements were made on natural and experimental stands. On natural stands, 15, 85 and 100% disease rates were determined on Fuchsia regia, Calendula officinalis and Zinnia elegans, respectively. Powdery mildews of C. officinalis and Z. elegans were identified as Podosphaera xanthii(Oidium subgenus Fibroidium). Disease symptoms were observed from early seedling to late maturing stages on Z. elegans, and from pre flowering to maturing stages on C. officinalis. The mildew pathogen of Fuchsia regia was identified as Leveillula taurica. This ornamental species appear to be resistant to this respected powdery mildew agent during summer, but somewhat susceptible in the early autumn. In addition, upper leaves were observed the only section displaying the disease. Key words: Podosphaera xanthii, Leveillula taurica, ornamentals, disease severity.