Understanding the Stages of Emerald Ash Borer Infestation: A Threat to Your Ash Trees

The Emerald Ash Borer (EAB) is a highly destructive insect that has devastated millions of ash trees across North America. Early detection and intervention are critical in managing EAB infestations and saving your ash trees. In this blog, we'll walk you through the stages of Emerald Ash Borer infestation, helping you recognize the signs and take timely action.

Stage 1: Initial Infestation (Year 1-3)

The first stage of EAB infestation is often the hardest to detect. During this stage, adult beetles lay eggs on the bark of ash trees, typically in the upper canopy. The eggs hatch within a few weeks, and the larvae begin to burrow into the tree, feeding on the inner bark and disrupting the tree’s ability to transport water and nutrients.

Signs to Watch For:

• D-shaped Exit Holes: As larvae mature into adults, they create small, D-shaped exit holes in the bark.

• Canopy Thinning: The first visible sign of infestation may be thinning leaves or branches in the upper canopy.

• Epicormic Shoots: The tree may attempt to produce new shoots or leaves directly from the trunk or lower branches as a stress response.

Stage 2: Progressive Damage (Years 3)

As the infestation progresses, the larvae continue to feed on the tree’s inner bark, causing more significant damage. The tree’s canopy will show more pronounced signs of decline, and you may notice additional indicators of EAB activity.

Signs to Watch For:

• Increased Canopy Thinning: More extensive leaf loss and branch dieback in the upper canopy.

• Bark Splitting: The tree’s bark may begin to split, revealing serpentine galleries underneath.

• Woodpecker Damage: Increased woodpecker activity as they hunt for larvae within the tree.

Stage 3: Advanced Infestation (Years 4-5)

By this stage, the infestation is severe, and the tree’s health is in significant decline. The tree may become structurally compromised, posing a risk to nearby property and people.

Signs to Watch For:

• Extensive Bark Splitting: Large sections of bark may peel away, exposing the galleries left by the feeding larvae.

• Increased Epicormic Growth: The tree may exhibit excessive growth of shoots from the base or trunk.

• Tree Death: In advanced cases, the tree may die within 4-5 years of the initial infestation.

Stage 4: Tree Death and Decay

If left untreated, an ash tree infested with EAB will eventually die. The tree’s wood will begin to decay, and it will lose its structural integrity, making it a hazard.

Signs to Watch For:

• Complete Canopy Dieback: The tree will lose all its leaves and branches.

• Structural Instability: Dead ash trees can become brittle and are prone to falling, posing a safety risk.

How to Protect Your Ash Trees

The best way to protect your ash trees from EAB is through early detection and preventive measures, such as tree injections. Tree injections deliver targeted treatments directly into the tree’s vascular system, helping to protect it from EAB larvae and other pests.

At Save The Ash Trees, we specialize in tree injection services that protect ash, oak, and elm trees from harmful diseases and insects like the Emerald Ash Borer. If you suspect an infestation or want to take preventive action, contact us today to schedule a consultation.