Fungus Alert: Learn the Signs of Oak Wilt!

Missouri counts many oak species among its native trees. Unfortunately, all oak trees are susceptible to a very common—and damaging—fungus known as Bretziella fagacearum. This fungus spreads across the water-conducting system of the oak tree, leading to rotting and wilting. The fungus and its damage are commonly called “oak wilt.”

Like all diseases and fungi, Bretziella fagacearum is introduced to the tree via contact with a source host. In the case of oak wilt, this host is a beetle that feeds on the sap of oak trees and deposits the fungus spores into open areas of the tree. The fungus grows and spreads, eventually leading to severe damage. Homeowners must understand the signs of this tree disease, as the dying or damaged tree can threaten their property.

Oak leaves showing oak wilt symptoms. Photo by Monique Sakalidis, Michigan State University.
Oak leaves showing oak wilt symptoms. Photo by Monique Sakalidis, Michigan State University

Table of Contents:

  • Types of Oak Trees in Missouri
  • Oak Wilt Symptoms
  • Oak Wilt Beetle
  • Treating Oak Wilt
  • Oak Wilt Treatment Cost


Key Takeaways: 

Oak wilt is caused by the fungus Bretziella fagacearum and is spread via oak-boring beetles. While some varieties of oak trees die quickly after contracting this fungus, others can survive for several years. Fungicide treatments can help protect oak trees on the property. Landowners must be vigilant in detecting signs of oak wilt, as dying trees pose a financial liability.

Types of Oak Trees in Missouri

Missouri is home to around a dozen species of oak trees. The state’s native oaks include:

  • Scarlet Oak Tree
  • Black Oak
  • Northern Red Oak 
  • Southern Red Oak 
  • Pin Oak 
  • Shingle Oak
  • Willow Oak
  • Water Oak 
  • Blackjack Oak 
  • Cherrybark Oak 
  • Shumard Oak

Scarlet Oak

The Scarlet Oak can grow to heights of around 80 feet. Acorns flourish in early fall (September and October).

Black Oak

This oak is known for its distinctive blackish bark. It reaches heights of around 85 feet.

Northern Red Oak

The Northern Red Oak grows to about 100 feet! Like other oaks, the Red Oak bursts with acorns in early fall.

Southern Red Oak

These oaks can reach heights of up to 90 feet. You’ll find them growing in southern Missouri.

Pin Oak

The Pin Oak grows to up to 100 feet. It is known as the pin oak, as the extensive number of branches leave behind pin-like knots or bumps on the wood. 

Shingle Oak

Shingle oaks grow up to 80 feet in height. The Missouri Department of Conservation explains that the name of the tree derived from colonists using the wood for roof shingles

Willow Oak

Willow Oaks grow to heights of 80 feet. They are located in Missouri’s bootheel.

Water Oak 

The Water Oak also grows to 80 feet, but it is a species of concern. These trees only grow in Ripley, Butler, Dunklin, and Pemiscot Counties (in or near the bootheel).

Blackjack Oak 

Blackjack Oak typically only grows to around 30 to 40 feet, but it can reach a height of 60 feet. The Missouri Department of Conservation notes that the bark looks like alligator skin (and is blackish in hue).

Cherrybark Oak 

Growing in and near the bootheel, cherrybark oak looks like cherry wood (thus its name). This oak species can grow up to 100 feet high!

Shumard Oak

The Shumard is a type of red oak, and it’s found around most of Missouri. The Shumard Oak hits a height of 100 feet. 


Oak Wilt Symptoms

All oak trees are susceptible to the Bretziella fagacearum fungus. Homeowners who are worried about the health of their oak trees may suspect this fungus when they notice the following symptoms and signs:

  • Brown and wilted leaves during summer (when all leaves should be green)
  • Dropping leaves
  • Dull olive leaves (or brown / bronze leaves)

As the fungus spreads, it emits a sweet sap that bugs and other pests (including squirrels) love. This allows the fungus to be carried from pests to other trees, continuing the cycle of infection and fungi infestation. The Missouri Department of Conservation states that red oaks may die from the oak wilt fungus within one year of infection, while other oak species may survive for longer. 

Oak Wilt Beetle

Typically, beetles are the primary pest to spread the oak wilt fungus. Beetles feed on sap and transmit fungal spores to open areas of a healthy tree. As oak wilt spreads, it emits a sweet sap that pests love. Again, this provides a natural cycle of transmission, as pests feed and move to a new healthy tree (where they spread the fungus).


Preventing and treating oak wilt is possible; professional arborists use powerful fungicides to protect healthy trees and manage early oak wilt infection. However, some trees with active and severe disease must be removed from the property to ensure the tree does not become structurally unsound.  

When homeowners suspect oak wilt infection, they should contact the team at S.M.B. Family Tree Service. Our team of arborists will assess the tree and determine the best course of action. In some cases, treatment is possible, and the tree can be saved. In severe cases of oak wilt, the tree must be removed from the property. 

Our team helps homeowners understand their options. We provide cost estimates to ensure there are no financial surprises. Schedule a consultation with S.M.B. and request a free estimate today!

Get A Free Estimate

  • This field is for validation purposes and should be left unchanged.

  

Contact Us Today for More Info!

(636) 212-1852

Call Now Button