Ramularia Leaf Spot -- Ramularia cyclaminicola
Host: Cyclamen, primula
Symptoms: The older leaves of mature plants can develop diffuse yellow areas and wilt. The fungus produces abundant spores on the undersurfaces of the yellowed leaves closest to the soil surface. On the lower surface of leaves, brown spots with indefinite margins can occur that may coalesce. Opposite these spots on the leaf’s upper surface, gray patches develop and then the leaves dry and collapse. Ramularia leaf spot also occurs on the older leaves of Primula where tan- or brown-colored spots that are angular in shape appear and can be accompanied by chlorosis.
Conditions Favoring Disease: Infects older leaves of mature plants.
How Pathogen Survives/Disperses: The fungus survives in soil and can be spread by soil movement, airborne conidia and as mycelium within the integument of seed.
Photo and write up provided by Syngenta Professional Products