What Is Wrong With My European Hornbeam?

Are the leaves covered with white powder?

Are the leaves small, discolored, and drop early, clusters of honey-colored mushrooms may sprout at the base of the plant?

Are there any sunken areas in the wood of the branch, stem or trunk that contains dead tissue?

Are the leaves covered by small bumps?

White, powdery patches on the leaves are caused by a fungal disease Powdery mildew. Powdery mildew usually appears in damp places. Encourage good air circulation around the affected plants by thining them and any surrounding plants. Water plants from bellow to keep foliage dry. Any affected leaves should be cut off and removed. Any commercial fungicidal spray will protect your plant from further infections.

Armillaria root rot is a fungal disease that cannot be effectively controlled once it has become established. Infected plants are very prone to wind breakage. Diseased or dead plants should be uprooted and removed. Avoid stressing trees by providing adequate irrigation, fertilization, and insect control.

Hypoxylon canker is a disease that attacks hornbeams. Prune out and destroy dead branches and infested areas. Be sure to make pruning cuts at least 3 or 4 inches below the canker and disinfect pruners between cuts. Spray both the healthy and diseased sections of a tree with copper during and shortly after periods of excessive rain.

If the leaves are covered by small bumps the culprits are scales. Scrape off minor infestations with your fingernail. Prune out badly infested growth, or use a soft brush and soapy water to gently scrub the scales off the stems. Control scales by spraying insecticidal oil during the growing season.

Both heart rot and decay fungus will greatly affect the life of the European hornbeam by destroying its structural support. These fungi cause the wood located in the center of the tree limbs and trunk to decay. If the conditions are ideal, the fungus can decay the wood rather quickly. Typically, the wood decay is not visible on the exterior of the tree. However, if the tree becomes injured you may be able to view the decaying cavity inside the tree. Defend the tree against heart rot and decay fungus by protecting it from injury and removing dead branches as soon as possible.