Herbicide Damage: Glyphosate and sulfonylureas

Photo by: R.S. Byther
Use IPM (Integrated Pest Management) for successful plant problem management.

Biology
Glyphosate is a nonselective herbicide (affects both grasses and broadleaf plants) which interferes with amino acid synthesis. It is translocated throughout the plant via both xylem and phloem. Damage is variable depending on the amount of herbicide involved and may range from slight yellowing of new leaves to death of the plant. Stunted, distorted, and narrowed yellowing leaves often have a pinkish cast. Multiple buds and shoots are stimulated, producing witches' brooms. Serrations on leaf margins may be elongated and strap-like. Plant death may be slow. Perennial plants exposed to nonlethal doses may show symptoms again the following season. Glyphosate is not persistent in the soil, so damage typically occurs due to drift or direct spray contact with green tissues. Damage caused by other amino acid-inhibiting herbicides, including sulfonylureas or imidazolinones, is very similar to glyphosate damage. However, these herbicides can persist in the soil for most of the growing season or from one growing season to the next, thus are more likely to be absorbed by plant roots. Therefore, symptoms may be seen on plants several days or even several months after the time of application.

Management Options

Select Non-chemical Management Options as Your First Choice!!
Revision Date:5/1/2013
Carefully read all label instructions prior to using glyphosate formulas. Use glyphosate products as spot treatments only!

Hortsense web site created by Carrie Foss, Pesticide Education, and Art Antonelli, Extension Entomology, WSU Puyallup
Pesticide information review provided by Catherine Daniels, Washington State Pest Management Resource Service
Database programs developed for Hortsense by Kathleen Duncan, Computer Resources, WSU Pullman
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