|
The best way to control leaf anthracnose is to spray dormant
lime-sulfur fungicide before the spring buds open. The buds,
twigs and branches should also be thoroughly soaked with dormant
products. The lime sulfur can be mixed with dormant oil (if
scale and gall mite control are needed) and sprayed on the
tree. Spraying a fungicide such as copper sulfate in late
spring may help control the early stages of the twig disease
and any new twig infections.
 |
| Ash leaf anthracnose close-up. |
 |
|
 |
|
Mancana ash twig showing early green anthracnose canker. |
|
Green
ash with anthracnose canker. |
Fungal Canker Disease
In the spring, frost cracks can become infected with Botryosphaeria
dothidea, which belongs to a broad category of fungal
canker diseases. The specific disease known to be associated
with ash tree frost injury in the United States is called
Fusicoccum aesculi. Canker diseases cause swollen,
sunken, or target-shaped wounds to develop randomly on the
branches or the main trunk. If these wounds grow large enough,
they can girdle the affected part of the tree, causing it
to die. Canker diseases should not be misidentified as mechanical
injuries.
Unfortunately, there are no effective treatments available
for control of these canker diseases. The only beneficial
control strategy is to improve tree health. Trees should be
watered during dry periods, mulched, properly fertilized and
protected against soil compaction. Severely affected trees
may not recover and must be removed. The canker opening can
be covered with a tree pruning sealant such as a paste or
tar to help prevent further drying of the exposed wood.
|
