Emerald Ash Borer Treatment Options for NY Landowners

Last updated: 2026-04-27

Chemical treatment can save individual ash trees from EAB. It cannot save a forest stand at reasonable cost. Understanding that distinction is the starting point for every treatment decision on private woodland in New York.

Need help deciding between treatment and harvest for your property? Call Henry at (845) 754-8242 for a free assessment.

How Systemic Insecticides Work Against EAB

Effective EAB treatments are systemic insecticides — products that enter the tree’s vascular system and are transported to the cambium where EAB larvae feed. When larvae consume treated tissue, they die before completing development.

There are two main delivery methods:

Imidacloprid: Soil Application

Granules or liquid concentrate applied to the soil at the base of the tree and taken up through the root system. Imidacloprid is the primary active ingredient in soil-applied products available to homeowners. Takes 4 to 6 weeks to reach effective concentrations in the canopy, making it less useful for trees already showing significant symptoms. Provides 1 to 2 years of protection per application.

Emamectin Benzoate: Trunk Injection

The insecticide is injected directly into the tree’s vascular tissue using specialized equipment, bypassing the need for soil uptake. Emamectin benzoate (TREE-äge) is the most effective product using this method, with documented control exceeding 95% in studies and protection lasting 2 to 3 years per application. Requires a licensed pesticide applicator.

When Treatment Makes Sense

Treatment is economically justified for:

Yard trees and ornamental ash near structures, where the tree has significant shade value, aesthetic value, or where removal would be expensive and disruptive. A large ash in an ideal location can be worth hundreds of dollars per year in energy savings and property value alone — making $30 to $60 per application economically rational.

Early-stage infestation where symptoms are limited to slight crown thinning and no exit holes are visible. Treating before larvae have established at high density gives the insecticide the best chance of breaking the infestation cycle.

Specimen trees with exceptional size, age, or ecological value — including large ash retained as mast trees in a managed forest stand.

When Timber Harvest Is the Better Answer

For forest stands — where the ash component consists of multiple trees per acre distributed across significant acreage — the cost-benefit of treatment almost never works out.

A simple calculation: 50 ash trees per acre on a 10-acre woodlot means 500 trees. At $30 per tree every 2 years, that is $7,500 per year in treatment costs, indefinitely, for an EAB population that will still be present in adjacent untreated stands. The stumpage value of those same 500 trees, if harvested while still merchantable, might be $30,000 to $60,000 — a one-time recovery that eliminates ongoing treatment costs.

For most private landowners in Sullivan, Orange, and Ulster counties with ash in their woodland, a selective harvest of the ash component — while the wood is still merchantable — makes more financial sense than sustained chemical treatment.

This is not a universal recommendation. Every property is different. Henry Kowalec assesses both options during a woodland walk and gives landowners a direct comparison based on their specific trees, their specific timber market, and their specific goals.

Biological Control: An Emerging Option

The USDA Forest Service and DEC have released three parasitic wasps from Asia that attack EAB at different life stages. These biological controls are not available for individual landowner purchase — they are released at selected sites by government agencies and are intended to reduce EAB populations at a landscape scale over decades.

They are not a treatment option for property-level management today but are part of the long-term strategy for managing EAB across New York’s forests.

Call (845) 754-8242 to discuss EAB treatment vs. harvest options for your specific property.

Henry Kowalec — Certified Consulting Forester — Environmental Forest Products, Westbrookville, NY

Frequently Asked Questions

What is the most effective emerald ash borer treatment?

Emamectin benzoate (sold as TREE-äge) injected directly into the tree's vascular system is considered the most effective EAB treatment — providing 2 to 3 years of protection per application with documented high efficacy even in moderately to heavily infested trees. It requires professional application equipment and a licensed pesticide applicator. Soil-applied imidacloprid (sold as Bayer Tree and Shrub Protect and Merit) provides 1 to 2 years of protection, is less expensive, and can be applied by homeowners, but is slower-acting and less effective than trunk injection for trees already showing moderate EAB symptoms.

Is EAB treatment worth it for forest trees?

Generally not, for stand-level management of forest ash. Treatment costs for systemic insecticides range from $15 to $60+ per tree per application, requiring renewal every 1 to 3 years. On a stand with 50 to 100 ash trees per acre, this cost exceeds the stumpage value of the timber for most landowners. Treatment makes economic sense for high-value shade trees near structures, ornamental ash in landscaped settings, and individual specimen trees with significant aesthetic or habitat value. For forest stands, timber salvage is almost always the financially sound alternative.

Can I treat ash trees with EAB myself?

Some soil-applied imidacloprid products are registered for homeowner use and can be applied without a license. Trunk injection with more effective products like emamectin benzoate requires a licensed pesticide applicator and professional injection equipment. For large forest trees on private woodland, the cost of professional treatment typically does not make sense compared to timber salvage — but for individual yard trees or high-value specimens, professional injection is worth considering in early-stage infestation.

What happens to ash trees if EAB is not treated?

Untreated ash trees infested with EAB die within 3 to 5 years of initial infestation in most cases. As the tree declines, its commercial timber value decreases — from full sawlog value in early infestation to pulpwood or no commercial value in advanced decline. Dead ash trees also become hazard trees relatively quickly, as the wood of dead ash deteriorates faster than many other species and large branches become prone to failure.