Pest information courtesy of USFS Fact Sheets:
Aphids will suck the sap from Sycamore. Heavy
infestations deposit honeydew on lower leaves and
objects beneath the tree, such as cars and sidewalks.
These infestations usually do no real harm to the tree.
Sycamore lace bugs feed on the undersides of the
leaves causing a stippled appearance. The insects
leave black flecks on the lower leaf surface, and cause
premature defoliation in late summer and early fall.
Some fungi cause leaf spots but are usually not
Anthracnose causes early symptoms on young
leaves resembling frost injury. When the leaves are
almost fully grown light brown areas appear along the
veins. Later the infected leaves fall off and trees may
be nearly completely defoliated. The disease can
cause twig and branch cankers. The trees send out a
second crop of leaves but repeated attacks can lower
tree vigor. Use a properly labeled fungicide accordingto the latest recommendations. Fertilization helps trees
withstand repeated defoliation.
Powdery mildew causes a white fuzz on the tops
of leaves and distorts leaves.
A bacterial leaf scorch can kill the tree in several
growing seasons, and can cause significant tree losses.
Leaves appear scorched, become crisp, and curl up as
they turn a reddish-brown.
Stress cankers form on limbs of trees stressed with
Sycamore Anthracnose Disease
More on Tree Insects and Disease