How Oak Wilt Infections Occur

Two Methods of Infections 

The oak wilt fungus infects oaks by two methods:

  • Long distance or overland transmission by insects
    • The insects pick up spore from diseased red oaks
    • They are attracted to sap from a wound in the bark of a live oak or red oak
      • Wounds from pruning
      • Wounds from limbs breaking off in the wind
      • Wounds from accident damage (e.g. by a lawnmower scraping the tree)
  • Local spread from tree to tree through roots

Insect carriers are always responsible for infection of the first oak in a neighborhood of otherwise healthy oaks. After the first oak has been colonized, the fungus moves through the roots to surrounding oaks, creating an oak wilt disease center.