PRESS RELEASE: (Missouri Department of Conservation) — American sycamore (Platanus occidentalis), is an easy tree for most Missourians to identify with its flaking bark and smooth, white upper limbs. This spring, sycamore trees are even easier to pick out on the landscape due to a leaf disease called anthracnose. Sycamore anthracnose has left many of our sycamores without most of their leaves, even as we make our way into summer.
Anthracnose is a name given to a variety of fungal diseases that affects many tree species and other plants. These fungi are common in spring and thrive during cool, wet weather. The recent heavy rains and cool temperatures have set much of the state up for perfect anthracnose conditions. Infected trees generally exhibit distorted leaves with brown, dead spots. Severe infections can cause shoot dieback and twig cankers. White oak, ash, maple, and walnut are among some common Missouri trees that also get anthracnose, although the fungal species causing the disease varies with each tree host.
If you’re walking around town or along streams and bottom areas, keep an eye out for sycamores. From a distance, it’s clear which trees are suffering from anthracnose due to their skeleton-like, leafless appearance. Some sycamores may only have leaves on the very tops of their crowns. On closer inspection, you might be able to see that the twigs and branches on some sycamores grow at very sharp angles. This happens because sycamore anthracnose can kill young twigs, causing new shoots to branch off at strange angles. This is especially noticeable in trees that have been hit by anthracnose many times.
Don’t be too worried by this spring’s spooky sycamores. They will produce new leaves as the weather warms up and dries out. In general, anthracnose is not a serious disease and control is not necessary, but repeated heavy infections can cause tree stress. If you have an affected tree in your yard, be sure to take good care of it this summer by watering it if drought conditions occur and keeping it properly mulched. For more info on anthracnose, species affected, and disease management tips, check out MDC’s Anthracnose of Shade Trees forest health alert.