Hickory - Hickory Tree Diseases

Diseases caused by Fungi:

Canker, Poria spiculosa.
This is the most serious disease of all of the hickories. Cankers form around dead branch stubs. These stubs appear to be nearly healed but brown fungus threads may be found in them, and thick, deep callus folds appear and cankers develop as rough circular swellings with depressed centers. This wood-rotting fungus will eventually spread through the tree.

No control is known, but cleaning and scraping the canker and removal of all discolored wood may help. Fertilize trees in the spring and water well during drought to maintain tree vigor.

Anthracnose, Gnomonia caryae.
This disease causes irregular purplish or reddish-brown spots on leaves and these spots may merge to form irregular shaped blotches. Although significant defoliation may occur after cool, wet spring weather, this disease is usually not serious to the health of the tree.

Rake and dispose of fallen leaves to reduce the chance of infection in the following season. Fertilize trees in the spring and water well during drought to maintain tree vigor. Since this disease is usually not a serious problem for the health of the trees, chemical controls are usually not necessary.

Witches'-broom. Microstroma juglandis.
These are bundles of twigs or small branches, or even very large branches, which resemble a broom. Usually more of a problem in the south, witches' broom at the ends of branches shows most clearly in winter. New leaves in spring are light in color and have the white moldy fruiting phase of the fungus on the underside.

Destruction of broomed twigs and fallen leaves will help to control the problem.

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