Causal Agent

Hypoxylon atropunctatum, H. mediterraneum 

 

Hosts

Hypoxylon canker occurs on many oak species (commonly blackjack, live, post, southern red, and white) and is found in forest areas and home landscapes. The disease is usually associated with stresses caused by drought, heat, wound or chemical injury. Thus, healthy trees are more resistant to the disease.

 

Symptoms

Leaves of trees infected with Hypoxylon turn yellow and wilt, and entire branches die. The bark sloughs off, exposing the stroma. The stroma may appear dusty brown, black, silver, or white depending on it's age as it progresses from it's asexual to sexual stage. 

 

Control

No effective means of control are available. Trees infected with Hypoxylon should be removed to prevent secondary infections on other susceptible trees. The spores from the stroma become exposed and are spread by rain and wind.