Since the causative agent of barley speckled barley disease, the fungus *Ramularia collo-cygni* , only appeared in Europe in the mid-1980s, it remained largely unknown to science for a long time. Extensive investigations into the biology of this fungus were conducted in Austria for the first time. Time-phase experiments demonstrated a strong dependence of symptom severity on the physiological developmental stage of the barley. To capture the genotypic resistance differences between winter barley varieties, the assessment data were adjusted for the influence of the timing of heading using a regression residual method.