Identification of powdery mildew disease on Gerbera jamesonii plants in Baghdad

تشخيص مرض البياض الدقيقي على نبات الجربراGerbera jamesonii في بغداد

Abstract

     Powdery mildew diseases cases have been seen on Gerbera plants Gerbera jamesonii Adlam. In the years 2008, 2009 and 2010 in some local nurseries of Baghdad city in the Palestine street (Al-Khirat and Al-Zina) and Zaiyuna (Zainab, Zaiyuna, Baghdad), disease percentage was between (33.33 -100%). The white powdery spots symptoms on leaves, stems and flowers were observed. A result of the diagnostic study was found to be Erysiphe cichoracearum the cause of the powdery mildew on the Gerbera plants (Cleistothecia, fruiting bodies was not founded in the infected plant parts). The study of pathogenicity was confirmed by dusting conidia on healthy plants and the symptoms were developed after a week on inoculation the plants, whereas control plants remained healthy. The disease incidences means were found high in the nurseries and there were significant differences between them in the three years.