Herbicide damage

What you see

Herbicide damage is an abiotic disorder that results from the exposure of non-target plants to herbicides. This can happen through drift, volatilization, or accidental application. The chemicals in herbicides can interfere with plant growth hormones, leading to a range of symptoms that can be mistaken for disease. Unlike diseases caused by pathogens, herbicide damage does not spread from plant to plant. Identifying herbicide damage involves looking for patterns of injury consistent with chemical exposure, such as uniform symptoms across affected areas or plants. The extent of damage depends on the type of herbicide, concentration, and the plant's sensitivity.

Symptoms

• Distorted or twisted leaves
• Yellowing or browning of leaf edges
• Stunted growth
• Leaf drop

Why it happens

Exposure to herbicides, either through drift, volatilization, or accidental contact.

Conditions that favour it

• Proximity to areas where herbicides are applied
• Windy conditions during herbicide application
• Use of herbicides in high temperatures
• Incorrect herbicide application rates
• Use of herbicides not labeled for the plant species

Plants most affected

• Tomato
• Pepper
• Grape
• Rose
• Oak
• Maple
• Bean
• Cucumber
• Petunia
• Zinnia

How to correct it

Educational information only, and not a substitute for professional diagnosis. Identify the problem before treating it, and check that any product is registered for this plant and this use where you live.

Prevention

• Apply herbicides carefully and according to label instructions
• Avoid spraying on windy days
• Use physical barriers to protect sensitive plants
• Select herbicides that are less prone to drift
• Educate applicators on proper techniques

Sources

• https://extension.psu.edu/herbicide-damage-to-trees-and-shrubs
• https://hortnews.extension.iastate.edu/2009/5-6/herbicide.html
• https://extension.umn.edu/herbicides/herbicide-damage