The development of foliar plant diseases on winter wheat with differing agronomic treatments was studied. The foliar diseases included powdery mildew (Erysiphe graminis) and diseases of the Septoria complex (Septoria spp. and Pyrenophora tritici-repentis) . Agronomic treatments included: nitrogen fertility, cultivar, and seed rate/row spacing. High nitrogen fertility, short stature, and wide row spacing were found to favour the development of powdery mildew. Short stature and high seed rate were found to favour the development of Septoria.