Spread of Oak Wilt
Spread Through Roots

Live Oaks tend to grow in large, dense groups with
interconnected roots. The fungus may be transmitted
from one tree to another through these root
connections. Root transmission is the only proven
means of spread among Live Oaks. As a result,
patches of dead, dying trees (Oak Wilt Centers) are
formed. Oak Wilt spreads through the root systems
at an average rate of 50 ft per year in all directions,
although travel at 150 ft in a single year is
documented, it is uncommon. Occasionally, the Oak
Wilt fungus is transmitted through connected roots
between Red Oaks, but movement is slower and
occurs over shorter distances than Live Oaks.
Establishment of New Infections and Spread by
insect Vector

Red oaks appear to play a key role in the
establishment of new Oak Wilt infection centers. The
Oak wilt fungus is spread overland by insect vectors,
and man through movement of wood from infected Red
Oaks only.

Spanish, Shumard and Blackjack Oaks play a unique
role in the spread, as these species are the only ones
known to produce a specialized spore producing
structure called a fungal mat, which develop
underneath the bark of infected trees. This fungal matt
only produces spores for 2 to 3 weeks in late Fall, but
most commonly in the Spring. Fungal mats are most
often developed on dead, standing trees, but can also
develop on logs, stumps and fresh firewood, all of
which, must have had the disease, prior to death. The
fruity odor of the fungal matt attracts the sap feeding
nitidulid beetles. The fungal spores are then
transmitted to other healthy Oak trees by way of
these insect vectors.