a guide to the recognition and understanding of ramularia and other ...

12
Later stage
SYMPTOMS
The rectangular lesions remain visible on the upper and lower side of
the leaf but the leaf dies back rapidly losing all its green leaf initially
turning yellow (chlorotic) before dying back completely. This die-back
usually starts to occur at the leaf tip. On the underside of the dead leaf,
translucent spores of Ramularia collo-cygni develop in lines coming
out from the leaf pores (stomata). These spores are not associated with
the dark rectangular lesions which will still be visible on the dead
leaves. The translucent spores can be seen using a magnifying hand
lens or occasionally by the naked eye. Wet conditions late in the season
can lead to a red colouration around ramularia leaf spot lesions on
dead leaves.
Later stage of ramularia leaf spot