Barley Powdery Mildew Disease Field Distribution on in North Eastern Syria, and Wetness Period Effect on Infection and disease Severity.

Abstract

Powdery mildew disease is an important disease on barley. To identify the distribution of the disease, field survey was conducted in 80 fields in 2016 and 86 fields in 2017 in different barley growing areas of Syria in (Malikya, Qamishli and Ras al aen) in north eastern of Syria. The effect of the length of wetness period was studied in relation to infection severity of disease on ten barley cultivars: (Furat2, Furat3, Furat4, Furat5, Furat6, Furat7, Furat9, Arabi Aswad, Arta, Acsad60) in seedling and tillers stage in laboratory. Results of powdery mildew survey showed that the distribution of disease was 55% in 2016, while it was 30.23% in 2017. The highest severity and ratio of infection was recorded in Malikya region. Results of study effect length of wetness  period in infection severity with powdery mildew disease at tillers stage showed that reaction of (Furat3, Furat4, Furat9 and Arta) was changed from susceptible (3.1-3.6 degree) at wetness periods (5, 7, 9,11 and 24 hours) to high resistant (1 degree) at wetness period (1 and 3 hours). Also the reaction of Furat5 and Acsad60 was changed from moderate resistant (2.3-2.6) to high resistant (1 degree). And reaction of Furat7 and Arabi Aswad was changed from sensitive (4.1-4.5 degree) at wetness periods above 5 hours to high resistant at wetness period (1 and 3 hours).While Furat2 and Furat6 was high resistant at different wetness periods. All tested cultivars were resistant to disease at seedling stage.  

Keywords: Powdery mildew, Survey, Wetness  period, Erysiphe graminis f.sp. hordei.