Herbicide Injury and Off-Target Drift

How Can Herbicides Injure Trees?

Trees can be particularly sensitive to certain herbicides. Off-target exposure may occur through spray drift, volatilization, runoff, or other pathways. Damage can vary depending on the herbicide, concentration, tree species, weather conditions, timing, and other factors.

Common symptoms of herbicide injury may include:

• Cupped, curled, twisted, distorted, or puckered leaves

• Narrow or strap-like leaves

• Stunted or unusually elongated shoots

• Distorted new growth

• Thinning or reduced foliage

Symptoms can vary among tree species and may resemble damage caused by insects, diseases, weather, or other environmental stresses. Herbicide injury should not be diagnosed from symptoms alone.

How Can Applicators Help Prevent Injury?

Applicators can help reduce off-target exposure by:

• Reading and following the pesticide label and all applicable Illinois regulations.

• Paying close attention to label restrictions related to wind, temperature, application methods, and sensitive vegetation.

• Checking weather conditions before and during application.

• Being aware of nearby woodlands, orchards, nurseries, gardens, specialty crops, and other sensitive vegetation.

• Using application methods and products appropriate for the site and conditions.

• Considering nonchemical weed-management practices when practical, including mowing, mulching, cultivation, or cover crops.

Good communication between landowners and applicators can also help prevent problems.

What Can Landowners Do?

Learn to recognize potential herbicide injury and monitor your trees, particularly when new foliage is developing. Keep records of when symptoms first appear, weather conditions, and any nearby pesticide applications.

If you suspect herbicide injury:

1. Document the damage. Take photographs of affected leaves, shoots, and entire trees. Record the date, location, tree species, and when symptoms were first observed.

2. Seek assistance with diagnosis. Contact your local University of Illinois Extension office or an Illinois Department of Natural Resources forester. Other causes of foliage damage should also be considered.

3. Report suspected pesticide misuse. The Illinois Department of Agriculture (IDOA) investigates complaints involving alleged pesticide misuse.

Reporting Suspected Pesticide Misuse

If you believe your property has been damaged by pesticide misuse, contact the Illinois Department of Agriculture, Bureau of Environmental Programs at 1-800-641-3934 or 217-785-2427.

IDOA recommends submitting a Pesticide Incident Complaint Form with as much information as possible. Complaints must be received within 30 days of the incident or within 30 days of when the damage was first noticed for an investigation or administrative action to be pursued.

Symptoms alone do not establish pesticide misuse. IDOA investigates complaints to determine whether a violation of the Illinois Pesticide Act occurred.

Illinois Department of Agriculture – Pesticide Information and Complaint Resources

Reduce the Risk of Off-Target Exposure

Communication among landowners, neighbors, and pesticide applicators is one of the best ways to reduce the potential for unintended exposure.

FieldWatch provides free, voluntary mapping tools that allow eligible producers and beekeepers to identify sensitive locations for pesticide applicators. Applicators can use the information as an additional tool when planning applications.

Visit FieldWatch

Learn More

Herbicide injury can be difficult to diagnose and may have multiple causes. When in doubt, document the symptoms and seek assistance from a qualified professional before assuming that herbicides are responsible.

The Illinois Forestry Association provides this information for educational purposes only. It is not intended to provide legal, regulatory, pesticide-use, or diagnostic advice.