by several fungi
- The greatest impact of anthracnose is in the urban environment.
Reduction of property values, resulting from the decline or death
of shade trees, is common. Various hosts are affected, including:
sycamore, oak, ash, dogwood, and walnut.
the Fungi. - The fungi which cause anthracnose are different
for each host. The fruiting bodies, which occur on twigs and leaves,
are distinctive in color and shape. Samples of affected twig and
leaf material should be sent to a specialist if this disease is
the Injury. - Injury usually includes irregular patches
of dead leaf tissue (blotches), blackened bases of the leaf stem,
cankering of the branch at the base of the leaf stem, and shoot
dieback. Cankering is not commonly seen on walnut.
on sycamore twigs.
- Infection of oaks and sycamores begins with the leaves. The
fungus grows through the veins, down the leaf stem, and into the
branch. The fungus survives through the winter in branch canker
tissue, and infection of emerging leaves occurs in subsequent
years from spores produced on these cankers. The fungi also overwinter
in diseased leaves in all hosts. Adverse impact of this disease
is directly related to heavy rainfall, low temperature, and low
- No control is practical in the forest due to the cost. In high
value trees, pruning, raking, and burning infected material, coupled
with fertilization, improves appearance and may reduce subsequent