How it Spreads
The Oak Wilt fungus most often spreads underground from infected trees to adjacent healthy trees through interconnecting roots. Sap beetles also carry fungal spores from infected trees to open cuts or wounds on healthy trees. The fungus can also be spread by pruning tools. Since fungal mats only appear on diseased Red Oaks or Spanish Oaks these trees must be removed immediately and chipped, burned or buried. Firewood can be used from infected Live Oaks if the wood is seasoned and properly dried.
Figure 4-9. Live Oak roots from separate trees grafted together. This is the primary way that Oak Wilt spreads from tree-to-tree.
Figure 4-10. Sap Beetles (Nitidulid Beetles) spreading Oak Wilt Fungus. Secondary vector of Oak Wilt fungus.