Bark Diseases on Orange Trees

The orange tree is susceptible to a variety of bark diseases.

The orange tree, Citrus aurantium, is a subtropical fruit-producing tree grown in temperate climates. Although the orange tree typically has hearty growth, a variety of bark diseases can affect tree health, according to Purdue University.

Sooty Canker

Sooty canker, caused by the fungal pathogen Hendersonula toruloidea, infects wounded orange tree bark. According to the University of Arizona, sooty canker turns tree bark tissue gray or black in color.

Phytophthora Foot Rot

Phytophthora foot rot, caused by the fungal pathogen Phytophthora, infects the roots of the orange tree and later infects the bark. According to the University of Florida, Phytophthora foot root causes bark peeling on orange tree trunks at the soil level.

Exocortis

Exocortis is a bark disease of the orange tree that causes bark shelling or scaling. According to the University of California, Davis, the disease causes dwarfing of young orange trees, where 5 to 25 percent of these trees exhibit bark shelling.

Control

The University of Arizona recommends pruning branches and limbs infected with sooty canker, as well as preventing unnecessary tree stress to control the disease. To control Phytophthora foot rot , reduce excess moisture near the root system and bottom of orange tree trunk, according to the University of Florida. The University of California explains the cause of exocortis is unknown; control consists of not using seeds from trees infected with the disease.

References

• Purdue University: Orange
• University of Arizona: Diseases of Citrus in Arizona
• University of Florida: Citrus Problems In The Home Landscape
• University of California, Davis: Exocortis of Trifoliate Orange