Extension Logo
Extension Logo
University of Minnesota Extension
extension.umn.edu

Herbicide injury on garden plants

Quick facts

  • Fruit, vegetable and ornamental plants can be injured by drift from herbicides that are sprayed on nearby lawns and crop fields to kill weeds. 
  • Herbicide injury symptoms depend on the herbicide applied and the garden plant species.
  • Know how to identify herbicide injury and tell it apart from other plant problems like nutrient deficiency and diseases.
  • Prevent herbicide injury by reducing or eliminating lawn herbicide applications, communicating with your neighbors and only spraying under certain weather conditions.

Herbicide drift happens when herbicides move through the air in droplets or vapor during an application, causing injury to nearby sensitive plants that they land on. Many fruit, vegetable and ornamental plants are sensitive to popular lawn and crop herbicides. Drift is most likely to occur during very windy, or very still (less than 3 mph) conditions. Any herbicide is prone to drifting if applied under the wrong conditions. 

Common herbicides that may drift

Some common lawn herbicides, also called “weed killers”, contain the active ingredients dicamba, 2,4-D or triclopyr. These growth regulator herbicides tend to have a low vapor pressure, or more tendency to evaporate.

Under the right conditions, they can vaporize in the hours or days after application, and move through the air. This is called volatilization. Spraying these products during or prior to hot, dry conditions increases the risk of off-target movement through volatilization. 

Glyphosate, the active ingredient in Roundup®, can also injure many types of garden plants when it is applied very close to them, especially during windy weather. It is a non-selective herbicide, meaning that it can kill a wide range of plant species.

Decreasing herbicide drift in your lawn and garden

  • Minimize herbicide usage and use non-chemical forms of weed control to decrease the risk of herbicide drift.
  • If your neighbors spray their lawn, communicate with them about your garden and ask them to avoid spraying herbicides in windy or hot, dry conditions. 
  • If you plan to spray your lawn, advise your neighbors, and take care to avoid spraying near their high-value plants, or when conditions favor drift or volatilization. 
  • Read the label on all herbicides before applying them to your lawn or garden, and know which active ingredients they contain. Each product is different: look for instructions about when and how to apply each product safely and responsibly. 
  • If hiring a lawn care company, alert them about your sensitive garden plants
  • Do not spray products containing growth regulator herbicides (listed above) during or prior to hot, dry, windy, or completely still conditions. 

Watering the lawn after growth regulator herbicides were applied may decrease the chance of drift through volatilization, according to research by Iowa State University.

Diagnosing herbicide injury

Refer to the photos in the drawers below to help determine whether damage on your fruit crops may be due to herbicide injury. Consider whether or not herbicides were recently sprayed nearby, either in your lawn or surrounding areas.

Sometimes, herbicide injury can be confused with other issues like nutrient deficiencies or plant diseases. Use What’s Wrong With My Plant to help diagnose plant problems.

 | 

Problems that can be mistaken for herbicide drift

Nutrient deficiency

Nutrient deficiencies can lead to yellowish leaves that may be mistaken for herbicide damage. 

  • Nitrogen deficiencies result in the yellowing of the oldest plant leaves, and potassium deficiencies result in yellowing along the leaf margins. 
  • If a nutrient deficiency is the issue, symptoms would likely be evenly spread throughout the area, affecting nearby plants similarly. 
  • By taking regular soil tests and applying nutrients as needed, you can avoid deficiency problems. 

Insect damage

Feeding damage from certain insects could be mistaken for herbicide injury. 

  • For example, squash bugs leave small yellowish-brown dots on the leaves of cucurbit plants like squash and cucumbers. Mild injury from a contact herbicide like glyphosate can look similar to this. 
  • Spider mites also leave yellowish-brown flecks on leaves that might be mistaken for glyphosate. 
  • In all cases, make sure to inspect your plants thoroughly. If insects are present, you should be able to find them by looking closely and investigating all parts of the plant, including underneath the leaves. 

Viruses

Mosaic viruses, such as squash mosaic virus and cucumber mosaic virus, cause uneven discoloration or “mottling” on the leaves that could be mistaken for injury from growth regulator herbicides. If you see these symptoms, submit a sample to the Plant Disease Clinic for diagnosis.

Winter injury on apples

Often when apple trees experience winter injury, they will still produce leaves before those leaves wilt and die at some point during the season. This wilting may be mistaken for herbicide injury.

Cane diseases on fruit trees and shrubs

  • Cane and spur blight diseases on raspberry kill the leaves and parts of the primocanes and floricanes. The brown, dead appearance can be mistaken for glyphosate injury.
  • Fireblight kills shoots, stems, and leaves of a variety of woody garden plant species, which can be mistaken for glyphosate injury.

Authors: Annie Klodd and Natalie Hoidal, Extension horticulture educators

Reviewed in 2021

Share this page:

© 2021 Regents of the University of Minnesota. All rights reserved. The University of Minnesota is an equal opportunity educator and employer.