Battling the Bronze Birch Borer

Seattle Tree Care experts talk options for treating bronze birch borer, from chemical treatments to at-home practices that can safe your birch tree

Native to North America, damage caused by the bronze birch borer (BBB) dates back to the late 1800’s and continues to present day. This pest is known to attack all native and non-native species of birch, although susceptibility varies. In Seattle, we often see our white-barked birch, paper birch, and Euorpean white birch trees impacted. 

The BBB is opportunistic and thrives in birch trees that are weakened or stressed by agents such as drought, soil compaction, root injury, other insects, and old age. Birch trees tend to prefer cool and moist growing sites, which are not typically found in most residential and urban areas. With frequent stress caused by dehydration, high temperatures, and compacted soils, landscape birch trees are commonly attacked by this pest.

Bronze Birch Borer Symptoms

Early symptoms of the BBB include yellow leaves, branch dieback, and an overall thin appearance to the upper part of the canopy. Larvae feed underneath the bark and disrupt the flow of water to the canopy. Wound tissue forms around these disruptions, creating a serpentine lump underneath the bark. Eventually the symptoms progress downward to the lower branches and trunk.

Adult beetles cause relatively little damage, but the larvae feed on the xylem layer and disrupt the movement of water and minerals within the tree. Early symptoms can be difficult to diagnose, but eventually the canopy dies from the top down.

Trees may be infested for several years before symptoms are visible in the canopy.

Claw of Death
Claw of Death 2

Options for treating Bronze Birch Borer

Preventively treating your tree is the best defense against BBB.

Adequate water is a key factor in maintaining healthy birch trees. A slow, deep watering event once per week during dry conditions will help maintain soil moisture levels and minimize the stress that invites the borer.


Pruning helps reduce the number of beetles in your tree and reduces the threat of dead limbs falling on your property. Pruning focuses on cutting deadwood down to where the tree is still alive and the wood is stable.

Chemical Treatments

Soil Application

Research trials have shown systemic insecticide treatments are highly effective at protecting birch trees. Current insecticide technology, Xytect and Mectinite, can protect your tree from BBB and other insects, including the birch leafminer.

Xytect and Transtect are systemic insecticides that protect the vascular system of the tree. Xytect should beapplied in the spring or the fall and Transtect should applied in the summertime. Both are at the base of the tree and are evenly distributed throughout the canopy by the pull created by the leaves. When the insect ingests the treatment they quickly stop feeding and die.

Transtect will provide rapid protection (within a week on most sized trees) and will last the entire season. Xytect can take up to 6-8 weeks to be active in the canopy but will provide 12 months of protection.Which treatment will berecommended is dependent on the timeof year the treatment will be applied.

Added Protection

Xytect or Transtect will alsoprotect your birch treefromtheseother insects: BirchLeafminers, Aphids, SpittleBugs, Flat HeadBorers, Leaf Hopper, Soft Shell Scale.

Early symtoms

Yellowing leaves and die-back of the tree's upper canopy

Mid-stage symptoms

Dieback spreads from the top down, infested limbs lack fine twigs

Late symptoms

Significant dieback, few or no fine twigs on infested limbs

Stem Injection

If you have a tree that is infested or a large tree that is in a high risk area, your arborist may recommend a treatment using Mectinite. Mectinite is applied by injecting it into the root flares of the tree and has been shown in University trials to get excellent control of actively feeding larvae. Mectinite works for 2 growing seasons.

D shaped holes
bbb treatment how does it work

Want more information on the bronze birch borer?

Download this sheet with details on identifying and treating the beetle.

About Seattle Tree Care

Seattle Tree Care has been offering stellar service in both residential and commercial areas since 2007. They provide Certified Arborist tree services along with 24/7 emergency service, and are licensed, bonded, and insured. Call them today for all your plant health care needs.

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