Abstract. Etiologic agent responsible for the powdery mildew disease in winter wheat is the fungus Blumeria graminis (D.C.) Speer. Powdery mildew is one of the main wheat diseases, present in all cultivation areas and it produces quantitative and qualitative yield losses by the shrinking of the grains. This fungus is present in every year in the wheat crops in Banat Plain, and is manifesting with different attack intensities depending by the climatic conditions. The evaluation of the fungus attack was realised on six wheat varieties: Apache, Azimut, Kalango, Karolinum, Soissons and Renan. The experimental field was placed within the perimeter of the Didactic Farm of Banat`s University of Agricultural Sciences and Veterinary Medicine “King Michael I of Romania,, from Timisoara. Intensity of the fungus attack was monitored as dynamics during two experimental years (2012 and 2013) during March – Aprilie period. There were realised observations in dynamics at every 10 in 10 days and from 12 to in 12 days. The attack of Blumeria graminis was evaluated by the calculation of AUDPC (area under the disease progress curve). The average value of AUDPC calculated for the two experimental years was comprised between 671.34 in Apache variety and 114.08 in Renan variety. The results obtained during the two experimental years shows the uniformity of the pathogen virulence, due to the climatic conditions very similar, both from point of view of the average temperatures registered and the rainfalls. Thus, the amplitude of the attack of Blumeria graminis fungus was comprised between 25.33 % (variety Renan) and 60.76% in 2012 is framing in the interval 20.78% (Renan) and 60.88% (Apache). According with the obtained results we can affirm that the most sensitive variety from the experimental plots was Apache ant the most resistant to powdery mildew was Renan. The other varieties from the research were tolerated well the pathogen, and the registered intensity was comprised between 40% and 50% in both experimental years.

Key words: AUDPC, Blumeria graminis, powdery mildew, wheat, virulence, variety.

Presentation: oral