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Diseases in Oklahoma Oak Trees

Red oak tree in autumn with blue sky and white cloud image by Freshwater Seas from

The oak tree is a large, deciduous tree that can live for more than 200 years. This expansive tree can reach heights over 100 feet tall with a spread more than half its height. These trees adapt to moist soils and have a low drought tolerance. Shumard, bur red and white oak trees adapt well to the Oklahoma climate and soil variations and are quite popular throughout the area. These trees, as well other oak variations, are susceptible to several diseases. These diseases can be permanently damaging to the tree, if left untreated.

Hypoxylon Canker

Hypoxylon canker is a causal fungal disease that attacks the tree internally. Oak trees are most susceptible when it is drought stressed, injured or recently transplanted. Outer wounds of an infected oak tree will begin to decay. Foliage will begin to yellow and wilt. The overall tree will experience die-back and growth stunt.

Though the disease may lie dormant in the tree for many years, symptoms often occur rapidly. Severely infected tree experience a seemingly rapid death. No chemical control for this disease exists. Infected trees must be removed and, as well as the tree stump, to prevent continual infection of the surrounding trees.

Oak Anthracnose

Oak anthracnose is a fungal disease common to oak trees. The young foliage of infected oak trees develops brown, deadened spots near the foliage veins. The margins of the leaves become deformed and severely infected foliage will curl. Leaves develop resistance to the disease as they age. However, mature foliage can become infected and develop brown spots. Twigs and branches may also become infected on severely infected trees and will experience dieback and growth stunt. White oak trees are the most susceptible of the oak family.

The oak anthracnose fungus lies dormant on defoliated debris under the oak tree prior to infecting the tree. Removal of defoliated debris greatly reduces the potential for anthracnose infection. A combination of copper-based fungicidal treatments and pruning of the infected areas helps to control the disease.

Oak Wilt

Oak wilt is a fungal disease that kills oak trees. Found mainly in the Midwest, this disease is commonly found near the eastern border of Oklahoma. Symptoms of oak wilt varying among oak tree species and include discoloration and browning of foliage, leaf curl, wilt, heavy defoliation, die-back and growth stunt. Though the disease kills red oak more quickly than white oak, bur and other oak trees, death of the infected oak tree is certain. Chemical treatments are not available for oak wilt and infected trees cannot be saved.

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