University of Arizona a dot Cooperative Extension


Herbicide Symptom Key

Branched chain (aliphatic) amino acid inhibitors - prevent the formation of the amino acids valine, leucine, and isoleucine and thereby reduce protein synthesis. Also have other secondary metabolic affects.

Symptoms - shoot meristems or growing points become yellow and die. Yellow streaks and pink and purple veins can develop on leaves. Root growth is also stunted.


Sulfonylurea herbicides

halosulfuron - Manage, Permit, Sandea
metsulfuron - Ally, Escort
prosulfuron - Peak
sulfometuron - Oust

  • Red veins (on cotton and alfalfa)

Photo of cotton leaves with red veins and some chlorosis.

Photo of red veins on alfalfa seedlings.

Imidazolinone herbicides

imazamox - Raptor
imazapyr - Arsenal, Chopper, Stalker
imazaquin - Image
imazethapyr - Pursuit

  • Buggy whipping (on corn)

Photo of buggy whipping of corn leaves.

  • Stunting (flat top)
  • Purple discoloration (on Johnson grass)

Photo of stunted and purple colored Johnson grass plant.

  • Lime green color (on cotton)
  • Cupping of upper leaves

Photo of cotton plants with lime green and cupped upper leaves.

  • Stacked nodes (on watermelon)

Photo of stacked nodes on a watermelon plant.

Pyrimidinyl oxybenzoate herbicides

pyrithiobac - Staple

  • Red veins (cowpea)

Photo of red veins on cowpea.

Full Disclaimers

Issued in furtherance of Cooperative Extension work, acts of May 8 and June 30, 1914, in cooperation with the U.S. Department of Agriculture, James A. Christenson, Director Cooperative Extension, College of Agriculture, The University of Arizona.

The University of Arizona is an equal opportunity, affirmative action institution. The University does not discriminate on the basis of race, color, religion, sex, national origin, age, disability, veteran status, or sexual orientation in its programs and activities.

Because labels are subject to frequent change, always consult the label attached to the product before using any pesticide. The user must assume responsibility for proper application and for residues on crops as well as for damage or injury caused by pesticides, whether to crop, person or property.

Any products, services, or organizations that are mentioned, shown, or indirectly implied in this web document do not imply endorsement by The University of Arizona.

Erin Taylor, etaylor@cals.arizona.edu Extension Agent, Field & Veg Crops
William B. McCloskey, wmcclosk@ag.arizona.edu Extension Weed Specialist
College of Agriculture, The University of Arizona, Tucson, AZ.
Material written June 2003.


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document located at: http://cals.arizona.edu/crops/weeds/key/parttwoC.html
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