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Herbicide Injury Symptoms
on
Corn and Soybeans


Department of Botany and Plant Pathology
Purdue University
West Lafayette, IN 47907



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This web page address is:
http://www.btny.purdue.edu/Extension/Weeds/HerbInj2/InjuryHerb3.html


Classified by Herbicide Active Ingredient

This section displays herbicide injury symptoms based on the common name (active ingredient) of the herbicide. You may click on an image to display it in larger detail. Most herbicide products will list the common name under the active ingredient section of the label. A cross reference list of trade names and common names can also be found in Weed Control Guidelines for Indiana WS-16.


Classified by Mode of Action

Select the "Classified by Mode of Action" link to view the section on herbicide injury symptoms based on the mode of action of the herbicide, e.g. 2,4-D is in the Growth Regulator family.


Herbicide Active Ingredient Index:

2,4-D | 2,4-DB | Acetochlor | Acifluorfen | Alachlor | Atrazine | Bromoxynil | Butylate
Chlorimuron | Clethodim | Clomazone | Cyanazine | Dicamba | Dimethenamid | EPTC
Ethalfluralin | Fenoxaprop | Fluazifop | Flumetsulam | Flumiclorac | Fomesafen | Glyphosate
Halosulfuron | Imazaquin | Imazethapyr | Lactofen | Metolachlor | Metribuzin | Nicosulfuron
Paraquat | Pendimethalin | Primisulfuron | Prosulfuron | Pyridate | Quizalofop | Rimsulfuron
Sethoxydim | Thifensulfuron | Trifluralin



Ethalfluralin, Pendimethalin or Trifluralin

Mode of Action: Seedling Growth Inhibitor

Click on an image to display it in larger detail.

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Corn Image

CORN

Mode: Seedling Growth Inhibitor
Herbicide: Ethalfluralin, Pendimethalin, Trifluralin
Injury: Clubbed or Swollen Root Tips

Condition: Carryover of herbicide due mostly to lack of moisture for breakdown or misapplication; stressed conditions (compaction)

Corn Image

CORN

Mode: Seedling Growth Inhibitor
Herbicide: Ethalfluralin, Pendimethalin, Trifluralin
Injury: Discolored shoot as a result of root injury

Condition: Carryover of herbicide due mostly to lack of moisture for breakdown or misapplication; stressed conditions (compaction)

Soybean Image

SOYBEAN

Mode: Seedling Growth Inhibitor
Herbicide: Ethalfluralin, Pendimethalin, Trifluralin
Injury: Clubbed or Swollen Root Tips; Swollen Hypocotyl

Condition: Overapplication of herbicide; stressed conditions (compaction)

Glyphosate

Mode of Action: Amino Acid Synthesis Inhibitor

Click on an image to display it in larger detail.

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Corn Image

CORN

Mode: Amino Acid Synthesis Inhibitor
Herbicide: Glyphosate
Injury: Bleached-white appearance of whorl or patches across leaf

Condition: Drift of herbicide; symptom expressed dependent on degree of drift

Imazaquin

Mode of Action: Amino Acid Synthesis Inhibitor

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Corn Image

CORN

Mode: Amino Acid Synthesis Inhibitor
Herbicide: Imazaquin
Injury: Short "Bottle-Brush" Lateral Roots

Condition: Carryover of herbicide to corn due mostly to lack of moisture for adequate herbicide breakdown; secondary - very low soil pH, soils high in clay and organic matter content

Corn Image

CORN

Mode: Amino Acid Synthesis Inhibitor
Herbicide: Imazaquin
Injury: Interveinal Chlorosis

Condition: Carryover of herbicide to corn due mostly to lack of moisture for adequate herbicide breakdown; secondary - very low soil pH, soils high in clay and organic matter content

Corn Image

CORN

Mode: Amino Acid Synthesis Inhibitor
Herbicide: Imazaquin
Injury: Stunting of Plant

Condition: Carryover of herbicide to corn due mostly to lack of moisture for adequate herbicide breakdown; secondary - very low soil pH, soils high in clay and organic matter content

Imazethapyr or Thifensulfuron

Mode of Action: Amino Acid Synthesis Inhibitor

Click on an image to display it in larger detail.

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Soybean Image

SOYBEAN

Mode: Amino Acid Synthesis Inhibitor
Herbicide: Imazethapyr, Thifensulfuron
Injury: Red Leaf Veins

Condition: Postemergence application made on days with high temperatures and humidity; misapplication

Nicosulfuron or Primisulfuron

Mode of Action: Amino Acid Synthesis Inhibitors

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Corn Image

CORN

Mode: Amino Acid Synthesis Inhibitor
Herbicide: Nicosulfuron, Primisulfuron
Injury: Yellowing of whorl, chlorotic patches across leaf, stunting of shoot; malformed leaves

Condition: Postemergence herbicide applied during high temps and humidity, during stressed conditions (drought, compaction, etc.) or following the application of an organo-phosphate soil insecticide

Corn Image

CORN

Mode: Amino Acid Synthesis Inhibitor
Herbicide: Nicosulfuron, Primisulfuron
Injury: Reduction in kernel rows from butt to tip of ear

Condition: Late postemergence herbicide applications where most of the corn leaves and whorl intercept the herbicide

Paraquat

Mode of Action: Cell Membrane Disruptor

Click on an image to display it in larger detail.

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Corn Image

CORN

Mode: Cell Membrane Disruptor
Herbicide: Paraquat
Injury: Necrotic spots

Condition: Herbicide drift from nearby field, most likely a no-till field where a burndown treatment of paraquat was applied

Pyridate

Mode of Action: Photosynthetic Inhibitor

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Corn Image

CORN

Mode: Photosynthetic Inhibitor
Herbicide: Pyridate
Injury: Burning of leaves

Condition: Herbicide applied postemergence; misapplication

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