Tree Problems in the O'Fallon Community

 Read the official handout!


What is the emerald ash borer?

The emerald ash borer (EAB) is an insect that has found its way into the O’Fallon community in the spring of 2014 and will create an infestation that is fatal to all species of ash trees. The EAB will spread through the community and begin killing only ash trees during the next eight years.

There are possibly 37,000 ash trees in the O’Fallon community that are essentially doomed to die from the Emerald Ash Borer infestation by the year 2022. It is essentially unstoppable and it has devastated ash trees over much of the country, starting in the Northern states. Eventually, the EAB will hit communities all the way to the Gulf of Mexico. It is just beginning to reach the City of O'Fallon.

Dead and dying ash trees pose a risk from their falling limbs.
Emerald Ash Borers leave a very distinct hole in a trees' trunk; note the half circle shape.
Emerald Ash Borer on top of a copper penny for size comparison
Closeup photo of an emerald ash borer


O’Fallon EAB:  Five Things to Know

  • Residents and businesses are responsible for tree removal on their property including trees between the sidewalk and the street.
  • O’Fallon staff will not diagnose EAB activity.
  • Remove ash trees when the tree reaches 50% dead or sooner if possible.
  • Residents can use O’Fallon’s yard waste program for disposing wood waste.
  • The City of O’Fallon encourages residents to plant trees where ever possible and as many as possible, even if you are not losing an ash tree.

What is the horned gall on oak trees?

The Horned Gall is killing oak trees at a faster rate than EAB. Huge trees that have survived adversity for 100+ years are surrendering to the Horned Gall in four to five years. The gall on the tree is a mutated growth of the tree in response to a very small wasp. The wasp deposits an egg and the newly hatched larvae burrow under, causing the tree to create a swollen mass of dysfunctional tissue which becomes the ideal home for the developing wasp larvae. The larvae will then develop into the next generation of wasp. Pin Oak, Scarlet Oak, Red Oak, Black Oak, and Water Oak are all very susceptible to the Horned Gall, and the worst part of this situation is that there are no measures or treatment protocols that can save these spectacular trees.


What is Callery Pear Decline?

Ornamental pear trees are referred to as Callery Pears. The name Callery includes ornamental pear cultivars such as 'Cleveland Select', 'Aristocrat', and 'Bradford'. The declining pear tree begins to show stress first by the leaves turning yellow and red. Eventually the leaves drop and after a few years the tree gradually dies. The consensus on Callery Pears is that the tree is invasive and no efforts are being made to diagnose the cause of the decline or save the pear trees.

 

Frequently Asked Questions about Trees

Can ash trees be saved from this infestation?

Can I dispose of the tree with the City?

Should I call the City if I think my ash tree has been infested?

What happens to a tree that is infested?

What is O'Fallon doing about the EAB?

Who is responsible for these ash trees as they deteriorate?


 Additional Resources

For additional information on the emerald ash borer, please check out these websites: