How Do New Jersey Homeowners Protect Trees From Emerald Ash Borer?

What is the Emerald Ash Borer and why it matters in New Jersey

The emerald ash borer, commonly abbreviated EAB, is a small metallic green beetle that attacks ash trees. Since its detection in North America in the early 2000s, EAB has killed tens of millions of ash trees and continues to expand its range. New Jersey has documented populations for years, and the insect poses a high risk to urban and forested ash trees because it feeds on the inner bark and cambium, disrupting the tree’s ability to transport water and nutrients.
EAB is especially problematic in developed areas where ash trees were commonly planted for shade, street tree programs, and residential landscapes. Untreated, EAB kills most infested ash trees within four to six years after the first signs of decline. That timeline makes rapid detection and action essential for homeowners who want to preserve large or high-value ash trees on their properties.

Identification: signs homeowners should watch for

Early detection is difficult, but there are consistent signs homeowners can learn to recognize. Look for any of the following on ash trees in late spring through fall:

• D-shaped exit holes in the bark where adult beetles have emerged.
• Vertical splits in the bark revealing winding S-shaped galleries in the inner bark.
• Thinning, dieback, yellowing, or sparse canopy at the top of the tree.
• Epicormic shoots or sprouts growing from the trunk or main branches.
• Increased woodpecker activity on the trunk or large limbs; woodpeckers often expose larvae.

If you see these signs, document them with photos, note their location, and contact a qualified arborist or your local cooperative extension office for confirmation.

Understanding local regulations and responsibilities in New Jersey

New Jersey has state and county-level actions addressing invasive pests like EAB. Quarantine rules and best management practices can change, so homeowners should consult state resources or local authorities to confirm current restrictions.
Common regulatory considerations include restrictions on moving firewood, requirements for disposal of infested wood, and permitted methods for treating or removing infected trees. Moving ash wood out of infested areas is a primary pathway for spread, so responsible homeowners should follow guidance on where and how to dispose of cut wood.

Integrated strategy for protecting ash trees: monitoring, prioritizing, treating, and removing

Protecting trees from EAB is not a single action but an integrated approach. This section outlines concrete steps homeowners should take and practical considerations for each.

1. Monitor and document tree health

• Inspect ash trees at least once per year in late spring or early summer and again in mid to late summer.
• Record tree location, species, diameter at breast height (DBH), and condition. Larger mature ash trees are often higher priorities for protection.
• Photograph symptoms and, if you suspect EAB, contact a certified arborist or county extension for a professional diagnosis.

2. Prioritize which trees to save

Not every ash tree can or should be saved. Consider these factors when deciding:

• Tree value: shade, historic or aesthetic value, screening, property value impact, and replacement cost.
• Tree condition: vigor, presence of structural decay, and remaining canopy. Trees already more than 50 percent dead are poor candidates for treatment.
• Location: trees near structures, driveways, or power lines may pose safety hazards if they decline.
• Diversity: in landscapes where ash comprises a large percentage of canopy, protecting select ash trees while beginning replanting with diverse species makes sense.

3. Treatment options: pros, cons, and schedules

There are effective insecticidal treatments that can protect ash trees from EAB when applied correctly and on the proper schedule. Treatments fall into several categories: systemic trunk injections, soil drenches/injections, and foliar or bark sprays. Key active ingredients homeowners should know include emamectin benzoate, imidacloprid, and dinotefuran.
Emamectin benzoate

• Generally applied by professional arborists as trunk injections.
• Provides strong protection and long residual activity, often two to three years per application depending on tree size and condition.
• Considered highly effective in preventing mortality for treated trees.

Imidacloprid (neonicotinoid)

• Available as soil drench or injection and sometimes as trunk injection.
• Effective for smaller trees and moderate infestations; residual action can last one to two years.
• Has documented risks to pollinators and aquatic organisms when misapplied, so follow label directions carefully.

Dinotefuran

• Fast-acting systemic that translocates quickly into foliage.
• Often used when rapid control is needed; residual typically shorter than emamectin.
• Can be applied as a trunk spray in some formulations or via soil injection.

Practical treatment guidelines

• Hire a licensed, experienced arborist for trunk injections and larger trees; incorrect rates or injection techniques can harm trees.
• For high-risk neighborhoods or trees with confirmed nearby EAB, start treatments before heavy infestation if the ash is high-value.
• Expect retreatment schedules: emamectin every 2 to 3 years, imidacloprid or dinotefuran often annually or every 1 to 2 years depending on product and infestation pressure.
• Never exceed labeled rates; pesticides must be used according to label for legal and safety reasons.

4. Removal and disposal of infested trees

When trees are heavily infested or pose safety risks, removal is the appropriate choice. Follow these practices:

• Use a professional tree service experienced with EAB removals.
• Do not move untreated firewood offsite; burn or chip wood on site if local rules allow.
• Chips smaller than 4 inches are generally considered low risk for spreading EAB if used on-site; confirm with local guidelines.
• Coordinate with neighbors and local authorities if multiple trees are affected in a block or street.

5. Replanting and long-term resilience

Replacing removed ash trees with diverse species reduces future pest risks and improves long-term urban forest health.

• Select species native or well-adapted to New Jersey soils and climate.
• Avoid planting large monocultures; diversify genera and functional groups.
• Consider size at maturity, canopy shape, and tolerance to drought, salt, and urban conditions.

Who should apply treatments: DIY versus professional applicators

Some homeowners can manage soil drench treatments on small trees using labeled homeowner products, but there are important caveats.

• Trunk injections and large-scale soil injections are best left to licensed professionals. They have equipment, knowledge of injection sites and timing, and understand how to calculate dose by DBH.
• Professional application reduces risk of improper dosing, soil contamination, and harm to non-target species.
• Always ask for proof of licensing, references, and written estimates. Request a treatment plan that includes expected retreatment intervals and warranty or follow-up service.

Environmental and safety considerations

• Avoid applying systemic insecticides during heavy bloom periods when pollinators are active, unless the product label permits and instructions are followed to minimize exposure.
• Prevent runoff into water bodies; many pesticides label restrictions address proximity to streams, ponds, and wells.
• Properly store and dispose of pesticides and treated containers per label instructions and local hazardous waste rules.

Costs and budgeting for protection

Costs vary by tree size, treatment type, and local labor rates. Typical ballpark figures:

• Professional trunk injections with emamectin benzoate: often several hundred dollars per treatment for medium trees, rising for very large trees. Treatments recur every 2 to 3 years.
• Soil drench or injection with neonicotinoids: lower per application costs but often require annual treatment; expect recurring annual expense.
• Tree removal and stump grinding: costs vary widely by size and accessibility; plan for significant one-time expense if removal is required.

Get multiple estimates, and include long-term protection or replanting in budget decisions. For many homeowners, investing in preventive treatment for high-value trees makes economic sense compared to loss and replacement costs.

Biological control and community-level approaches

Biological control programs releasing parasitoid wasps that attack EAB larvae and eggs are part of long-term landscape-level management. These agents can help slow EAB population growth but are not a sole solution for protecting single urban trees today.
Community action amplifies effectiveness. Municipalities and neighborhood associations that coordinate monitoring, treatment subsidies, removal campaigns, and replanting programs reduce the overall impact on the urban forest and lower per-household costs.

Final practical takeaways for New Jersey homeowners

• Learn to identify ash trees and early signs of EAB; annual inspections are essential.
• Prioritize saving high-value, structurally sound trees. Treat proactively if EAB is nearby.
• Choose treatments based on tree size and infestation pressure: emamectin benzoate injections for long-lasting protection, neonicotinoids for lower-cost options with more frequent retreatment, and dinotefuran for rapid knockdown.
• Hire licensed, experienced arborists for injections and for decisions about removal; improper application can harm trees and the environment.
• Follow state and local rules about moving firewood and disposing of infected wood to reduce spread.
• Plan for long-term resilience by replanting with diverse, appropriate species to replace ash trees removed to manage risk.

Protecting trees from emerald ash borer requires informed, coordinated action. With timely monitoring, the right treatment choices, and responsible disposal and replanting, New Jersey homeowners can preserve valuable ash trees and maintain resilient urban and suburban canopies.