Peronospora lapponica Lagerheim, 1888
upperside of the leaves locally bleached; at the corresponding underside a greyish-purple fungal bloom consisting of erect, distally strongly branched conidiophores, 0.4-0.7 mm high; conidia elliptic in shape.
Euphrasia frigida, rostkoviana.
contrary to Plasmopara euhprasiae, that also may occur on the host plant mentioned above, P. lapponica does not cause a disturbance of the growth of the plant.
Blumer (1946a), Brandenburger (1985a), Buhr (1964b), Gäumann & Blumer (1947a), Klenke & Scholler (2015a).