The following is from Wikipedia regarding this disease:
Infections and symptoms
Oak wilt spreads in two basic ways. A transmission via root graft is the most common source of infection, as trees within as much as 15 m (50 feet) of an infected tree can be infected. The second method of infection is via sap beetles. These beetles are attracted to the bleeding sap of the oak tree, as well as the fungus in an infected or dead tree, and so can transfer the disease to healthy but injured trees. This is less common as trees are rarely infected this way unless injured, but it is the only way to jump barriers (rivers, for example) and infect trees in new areas
Oak wilt is identifiable by the rapid pattern of wilting starting from the top of the tree and progressively dying down to the bottom, and on specific
leaves , wilting from the edges to the base. Oaks with oak wilt stand out with their dead crown compared to a green canopy in the summer, so much so that oak wilt infections can be spotted from the air. A new infection via beetles instead of root grafts can kill a tree somewhat more slowly, if a branch is infected instead of the trunk.
Effects on species
Oak wilt affects all oak species, but has somewhat different effects on different groups. Oaks in the red oak group (black, northern red, northern pin and others with pointed leaf edges such as live oak) are particularly susceptible and, when infected, generally die over the course of a single summer. Oaks in the white oak group (white, swamp white, bur and others with rounded leaf edges) are less susceptible, and are more resistant when infected (White Oak in particular), and can live for several years after infection, losing a few branches each season, from the top down. Some types of white oak, such as Bur Oak are more susceptible, although still not as much as red oaks.
Oak wilt usually moves from diseased trees to healthy trees through roots that have become interconnected (root grafts). Most root grafts form between oaks of the same species; red oak roots graft more commonly than do white oak roots, and grafts between red and white oaks are very rare. Although possible, it is rare for oak wilt to jump between oaks of different species via root grafting – different species do not graft often, and so contaminate each other less frequently.
Some treatments, like trenching and application of anti-fungals, can help but are not guaranteed. It appears that the best solution is to start planting oak wilt “resistant” trees. Tim Redicker of Scenic Hills Nursery has an excellent site with some suggestions on trees.
The Texas Forest Service has a great program for offering tree seedlings at an affordable price. For example, they offer Chinkapin Oak seedlings for $1 each in lots of 25. The next sale begins this September (2010). For information visit the TFS Online Seedling Store.
So, after you shed your tears over the loss of your trees, get you shovel and rock bar ready to plant replacement trees/seedlings this Fall.