Fig 1 Hypoxylon beneath bark of disease tree.

The disease is caused by a fungus named Biscogniauxia (Hypoxylon) atropunctatum. This fungus is an opportunistic pathogen, meaning it does not affect healthy and vigorous trees. However, Hypoxylon can quickly colonize weakened or stressed trees. It has been diagnosed on trees growing in many different habitats, such as forest sites, pastures, parks, green spaces and urban development areas. Hypoxylon canker can affect any type of oak, including; black, blackjack, laurel, live, post, southern red, Texas red, water and white oaks.
Since Hypoxylon is a fungus, it spreads from diseased to healthy trees by spores. Opportunistic fungi, however, are usually already present on many trees, causing disease when tree resistance is insufficient to prevent them from infecting. There are many sources of stress capable of decreasing the resistance of trees to  opportunistic pathogens.

Fig 2. Typical site disruptions during home construction.

drainage issues and suffocate roots. All these factors set in motion a chain of events leading to stress, decline and tree death (Figure 2). During  decline,
Hypoxylon attacks the  trees and contributes to their mortality.
Natural factors Climatic conditions such as heat, drought, ice storms, hail damage, lightning, and flooding are capable of predisposing trees to infection by Hypoxylon. Insect attacks and other diseases, such as oak wilt and root rots, induce stress and cause a tree to be susceptible to infection by Hypoxylon.
Symptoms and Signs and Control of Hypoxylon canker are covered in Parts 2 and 3 of these fact sheets.