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Spread of Oak Wilt
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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. |
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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. |
