Fact Sheet

Two-Lined Chestnut Borer

Have you noticed small D-shaped holes in oak tree bark or signs of wilting and tip-dieback?

It may be from the two-lined chestnut borer.

The Problem

Adult beetles emerge in late spring, leaving D-shaped exit holes, and lay eggs on stressed oaks. The larvae tunnel under the bark, feeding on vital tissue and disrupting the tree’s ability to move water and nutrients—leading to dieback and further decline.

Symptoms and signs include:

Small D-shaped exit holes in the bark
Wilting or yellowing leaves, especially in the upper canopy
Tip-dieback and progressive branch death, often starting at the top of the tree
Tunneling under the bark

Co-occurring issues or look-alike symptoms:
Oak wilt, bur oak blight, armillaria root rot, and drought stress.

The Vineland Prescription

For chestnut borer treatment, trunk injections or soil-applied products provide excellent control.
Mulching and watering to increase vigor and reduce stress.

The Prognosis

If underlying cause of stress can be addressed, trees can generally recover from most moderate infestations.

Contact Our Experts

From questions to estimate requests, contact us about your residential or commercial project.