Over the past few weeks, many of the phone calls and house visits have concerned one thing, Sycamore trees looking sick. Many of the Sycamore tree leaves in the area are turning brown in spots, and are dropping off the tree leaving it looking stressed early in the growing season. I have went and checked out several of the trees that are having this issue, and it seems to be Sycamore Anthracnose.
Anthracnose is a general term used to describe a group of fungal diseases whose symptoms include foliar and/ or twig blighting. The fungi overwinter in leaf debris on the ground or dead areas of the bark on the tree. The infection is favored by cool temperatures and wet weather. During springs like the one we experienced this year, the fungus may kill leaf buds and expanding shoots, possibly giving the tree a ragged appearance. Leaves may also develop elongated tan to brown lesions along the veins. Trees that may be affected with anthracnose include ash, elm, maple, oak, black walnut and sycamore.
Anthracnose rarely causes significant damage to the deciduous trees in Kansas, so typically control measures are not recommended.  As the temperatures increase, the disease becomes less active and the trees will throw out new leaves. Cultural practices however, may help the severity of the disease in subsequent years. Removing leaf litter in the fall, proper spacing, and proper watering to keep the tree vigorous will allow it to recover rapidly as conditions improve. There are chemical sprays labeled for control of anthracnose if the tree is in a high visibility landscape that would constitute chemical control. For most affected trees though, a little extra care will help your tree rebound as the weather dries out and continues to warm up.
Alicia Boor is the Agriculture and Natural Resources agent for Barton County K-state Research and Extension. One can contact her by email at aboor@ksu.edu or calling 620-793-1910