What is Sycamore Anthracnose?

Sycamore anthracnose is such a serious disease for the American sycamore that the Colorado University State Extension recommends avoiding planting that particular species. The London and Oriental plane versions of the tree are less susceptible, but can still be affected by the fungus.

The fungal disease typically causes leaf drop, twig dieback, cankers (sunken spots). More than 90 percent of a Sycamore’s new shoot growth can be affected and sudden death of new growth is not uncommon. The disease itself is usually not fatal, but repeat infections weaken the tree, increasing the risk of infestations by pests or contracting other diseases.

Signs of sycamore anthracnose

Most trees with the Sycamore anthracnose exhibit signs in the early spring, so anthracnose is often misdiagnosed as frost damage. Young leaves appear withered as they unfold. Older leaves turn brown in spring and drop by mid-summer. Cankers develop on the tree trunk and main branches. Because tree wounds don’t heal, the unsightly cankers often result in misshapen areas as the rest of the tree grows around them. Some branches may be so severely affected by the canker that they die.

Spring rains help spread anthracnose spores that overwintered on diseased leaves and cankers. The spores germinate at 50-55 degrees F. The window for germination is small (60 degrees F is already too hot for germination) so property owners are often lulled into a false sense of security. But fungi are one of the world’s oldest forms of life and it takes much more than a sunny day in the 60s to stop them.

The second set of leaves that emerge on an infected sycamore in mid-summer is as much at risk as their springtime predecessors. If you suspect Sycamore anthracnose, contact SprayTech, Colorado commercial and residential weed-spraying specialists, at 720-248-0000 to discuss treatment options. Providing tree services to the Front Range, South Metro Denver areas.