Emerald Ash Borer (EAB) Tree Injection Protocol

Why this matters

Emerald Ash Borer (Agrilus planipennis) has killed hundreds of millions of ash trees across North America since its 2002 discovery in Michigan. The pest continues to expand its range. For ash trees not yet infested or in early infestation (under 30 percent canopy thinning), professional trunk injection with a systemic insecticide is the only proven preservation treatment. Untreated ash trees in established EAB zones die within 3 to 5 years of infestation. A correct injection protocol gives the homeowner a decade-plus of continued tree value; an incorrect protocol wastes the chemical and the homeowner's investment.

When injection is the right choice

Injection is indicated when:

• The tree is an ash (Fraxinus species: white, green, black, blue, pumpkin, or Carolina ash)
• The site is within or near a confirmed EAB-positive county
• The tree is structurally sound and has less than 30 percent canopy thinning
• The trunk diameter at 4.5 feet (DBH) is between 4 inches and roughly 40 inches (over 40 inches, injection labor cost climbs while injection effectiveness does not, but treatment is still appropriate)
• The customer commits to retreatment on the labeled cycle (most products: every 2 to 3 years)
• The tree is in a location where its loss would cause significant damage or aesthetic loss

Injection is not appropriate when:

• The tree has more than 50 percent canopy dieback (recovery is unlikely)
• The tree has structural defects unrelated to EAB that warrant removal
• The tree is in a remote location where biannual treatment access is impractical
• The customer cannot or will not commit to the retreatment schedule

Treatment product selection

The dominant professional EAB treatment is emamectin benzoate, marketed primarily as Mauget TREE-age (Arborjet's product, the most common in the trade) and TREE-age G4. Emamectin benzoate provides 2- to 3-year EAB control from a single injection, with research showing 90+ percent twig protection through year 2 and around 70 percent at year 3.

Other systemic options used in lower-pressure situations:

• Imidacloprid (soil drench or basal trunk spray): lower-cost, 1-year residual, less effective on established infestations than trunk-injected emamectin
• Dinotefuran (basal trunk spray): faster uptake than imidacloprid, 1-year residual, useful for late-season treatment

For protection in EAB hot zones with significant infestation pressure, emamectin benzoate trunk injection is the field standard. Soil drenches with imidacloprid are used as preventive treatment in low-pressure areas where annual retreatment is feasible.

Equipment

The Arborjet QUIK-jet AIR or QUIK-jet (pressure-driven) systems are the dominant trunk-injection delivery devices. Each system:

• Threads injection plugs into pre-drilled holes around the trunk base
• Delivers measured chemical doses through the plugs into the xylem
• Uses CO2 cartridge or hand-pump pressure to drive chemical uptake

Alternative systems (Mauget capsules, Rainbow Treecare's QUIKjet competitors) follow similar principles.

The applicator must be a licensed pesticide applicator in the state where work is performed. Most states require a Category 3A or equivalent license for ornamental tree treatment. EPA reciprocity does not exist; verify license per state of work.

Site assessment

Before treatment:

• Verify tree species (ash). Mountain ash (Sorbus) is not Fraxinus and is not an EAB host.
• Measure DBH (diameter at 4.5 feet above grade) for dose calculation. Calculate the per-tree dose per the product label. TREE-age dose is approximately 0.2 mL per inch DBH for healthy trees; consult current label for the binding spec.
• Assess canopy condition with binoculars: count percent dieback by reference to a healthy ash canopy. Document with photos.
• Identify any environmentally sensitive areas: ponds, wells (drinking-water wells trigger label setback requirements), pollinator hives, edible gardens beneath the canopy.
• Check the calendar: optimal injection timing is after spring leaf-out (mid-May through July in the Midwest and Northeast) when the tree is actively transpiring. Late-season injection works but uptake slows.

Injection procedure

1. Clear the trunk base. Remove loose bark, mulch, and debris from the injection zone (the lower 12 inches of trunk).

2. Drill injection ports. Spacing: one port per 5 to 6 inches of trunk circumference. A 24-inch DBH tree has circumference of about 75 inches and needs roughly 12 to 15 ports. Drill at the root flare or just above, angled slightly down into the trunk. Drill bit per system manufacturer specification (typically 3/8 inch for the standard Arborjet plug).

3. Insert injection plugs. Tap the plug flush with the bark using a rubber mallet. The plug's check valve prevents backflow.

4. Connect the injection device to each plug in turn. Inject the calculated dose per port. Allow uptake (the tree should "take" the chemical in 15 to 90 seconds per port depending on transpiration and chemical viscosity).

5. Continue around the trunk until the full per-tree dose has been delivered. If a port refuses to take chemical, move to a neighboring port and inject a partial overdose to compensate (do not exceed label per-tree maximum).

6. Remove plugs per the system instructions. Most current Arborjet plugs remain in the tree as a record of the treatment site; the tree compartmentalizes around them.

7. Document the treatment: date, product, lot number, dose per tree, port count, weather conditions, applicator license number, and re-treatment date. Keep records per state pesticide-application recordkeeping rules (typically 2 to 3 years minimum).

Drilling minimization

Each injection port is a wound. Although the tree compartmentalizes around the plug, repeated injections at the same trunk locations accumulate decay over decades. For trees on a long-term protection plan, rotate the port locations on each retreatment cycle so that the same bark area is not drilled twice in three treatments.

Retreatment schedule

• TREE-age and TREE-age G4: 2 to 3 years between treatments per current label and university extension recommendations.
• TREE-age R10: a newer formulation with extended residual; check current label.
• Imidacloprid soil drench: annual.
• Dinotefuran basal bark spray: annual to biannual.

Document the customer's retreatment schedule in the work order and the service-business CRM. Send the retreatment-due notification 60 days before the window opens.

Pollinator and environmental considerations

References

• US EPA Pesticide Product Label Database - search "emamectin benzoate" for current TREE-age labels
• USDA Forest Service Northern Research Station - Emerald Ash Borer Information Network (emeraldashborer.info)
• Herms, D.A. et al. - Insecticide Options for Protecting Ash Trees from Emerald Ash Borer (multi-state university extension bulletin, current revision)
• Federal Insecticide, Fungicide and Rodenticide Act (FIFRA), 7 USC Section 136
• ANSI A300 (Part 7)-2018 - Integrated Pest Management