Guignardia Leaf Blotch | |
|---|---|
|
Horsechestnut and buckeye trees that appear from
a distance to be severely scorched may actually be infected
with this fungal disease. On closer
inspection, reddish brown leaf spots with bright
yellow margins are obvious. The spots will enlarge
and cover most of the leaf surface. Leaves then
become dry and brittle and drop early. You can
distinguish this disease from environmental scorch by
the presence of fruiting bodies formed by the
fungus (Guignardia aesculi) in the leaf lesions in
moist weather. These black, pinhead-sized structures
are called pycnidia. With Guignardia leaf blotch,
all leaves will be affected, unlike with scorch,
which first affects newest leaves on the sun or wind side
of the tree.
This disease is serious yet treatable in
nursery stock. Mature trees usually retain live buds and
lose leaves late in the season, so they are not
significantly harmed. Removing fallen leaves may be helpful
in reducing the amount of fungal inoculum living through the
winter on these leaves. Also try to
prune surrounding vegetation to allow better
airflow through the area for more rapid drying of
foliage.
| |
| Author: | Nancy Pataky |
