Herbicide Injury vs Dutch Elm Disease

Herbicide injury — particularly from 2,4-D, dicamba, glyphosate, and triclopyr — produces wilting and leaf damage that can look like the early stages of Dutch Elm Disease to an untrained eye. Unlike DED, herbicide damage usually traces to a specific recent application and produces distinctive leaf abnormalities.

What herbicide injury is

Trees can be exposed to herbicides several ways:

Drift from nearby spraying (neighbor's lawn, county roadside, agricultural field)

Root uptake from herbicides applied to lawns within the root zone

Direct contact with trunk or low foliage

Volatilization in hot weather causing chemicals to drift far from application site

Different herbicides cause distinct symptoms, but several produce wilting and leaf abnormalities that mimic DED in mild cases.

Where they overlap

Both conditions can:

Cause leaf wilting

Produce yellowing or browning leaves

Cause branch decline if severe

Affect parts of the canopy unevenly

How to tell them apart

Feature | Dutch Elm Disease | Herbicide injury
Leaf shape | Normal until necrotic | Often distorted: cupped, twisted, strap-shaped, or rolled
Vein patterns | Normal | Pronounced/altered venation; often parallel veins
Vascular streaking | Yes — chocolate brown | None
Pattern within tree | Branch-by-branch | Often one side of tree facing application source; or whole tree
Other plants affected | No | Yes — nearby shrubs, garden plants, lawn weeds may show symptoms
Timing relative to spraying | Unrelated | Within 1–3 weeks of recent application
Recovery in next growth flush | None | Often partial recovery if exposure was single event

The leaf shape test

This is the most reliable distinguishing feature. Pull a symptomatic leaf and look closely:

DED: leaves look normal in shape until they wilt and brown; no twisting or cupping

Glyphosate injury: small, narrow, twisted, sometimes white-tinged new leaves

2,4-D / dicamba injury: cupped, strap-shaped, or twisted leaves with prominent parallel veins

Triclopyr injury: leaf curl and bleaching on new growth

Distorted leaf morphology is never caused by Dutch Elm Disease. If new leaves are cupped, twisted, or shaped unusually, it's herbicide injury or another stress factor — not DED.

Why misdiagnosis matters

Treating herbicide injury as DED with fungicide injections wastes money on an ineffective intervention. The tree needs:

Time to recover (one growing season, sometimes two)

Identification and removal of the exposure source

Standard supportive care (water, mulch, no additional stress)

Herbicide injury is generally not progressive once the exposure ends — the affected leaves don't recover, but new growth typically returns to normal.

When to suspect herbicide injury

Consider herbicide injury when:

A recent (within weeks) lawn or roadside spraying occurred nearby

Leaves show distorted shape, cupping, or twisting

New growth looks more affected than old growth

Other plants (shrubs, gardens, weeds) show similar symptoms

The damage pattern aligns with prevailing wind direction from a known spraying source

The tree was sprayed accidentally during lawn herbicide application

Confirmation

Herbicide injury cannot easily be confirmed by lab testing — by the time symptoms appear, residues are often below detection limits. Diagnosis is usually based on:

Symptom pattern (especially leaf morphology)

Application history in the area

Process of elimination (ruling out DED, anthracnose, etc.)

Management

Identify and stop the exposure source

Water thoroughly to encourage flushing of root-absorbed herbicides

Apply 2–3 inches of mulch over the root zone

Avoid additional stressors (no pruning, no fertilizing the affected year)

Wait through one full growing season before evaluating recovery

Related pages

Differential Diagnosis Guide

What Are the Symptoms of Dutch Elm Disease?

Drought Stress vs Dutch Elm Disease

Dutch Elm Disease Symptom Checker

References

Felsot, A. S., et al. (2011). "Agrochemical spray drift; assessment and mitigation — A review." Journal of Environmental Science and Health, Part B, 46(1), 1–23.

Eggers, J. H. (1983). "Herbicide injury to trees and shrubs." Iowa State University Extension.

Kruse, R. R., & Nair, V. M. G. (1971). "Effect of herbicides on tree growth." Weed Science, 19(5), 580–582.