Plant Pathology Department, University of Kentucky

Diagnostic Training Images

Herbicide Injury

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Last Modified: 07-Jun-2012
Copyright © 2004, University of Kentucky, College of Agriculture, Department of Plant Pathology

glyphosate ("Roundup") on Pepper, Cantaloupe, Potato Tomato, Blackberry, Corn (scroll down)

Plant: Pepper (Capsicum annum) (Solanaceae) Back to List
Disease/Disorder: herbicide injury
Causal agent: "Roundup" 'glyphosate'
Signs:
Symptoms: Yellowing of youngest leaves from the base.
Total image number: 2

Plant: Cantaloupe (Cucumis melo spp.) Back to List
Disease/Disorder: herbicide injury
Causal agent: "Roundup" 'glyphosate'
Signs:
Symptoms: Yellowing of youngest leaves from the base.
Total image number: 4

Plant: Potato (Solanum tuberosum) (Solanaceae) Back to List
Disease/Disorder: herbicide injury
Causal agent: "Roundup" 'glyphosate'
Signs:
Symptoms: Yellowing of youngest leaves from the base.
Total image number: 4

Plant: Tomato (Lycopersicon esculentum) (Solanaceae) Back to List
Disease/Disorder: herbicide injury
Causal agent: 'glyphosate' ("RoundUp")
Signs: none
Symptoms: Plant foliage, especially new growth, will yellow first and then turn brown and die.
Total image number: 8
1st and 2nd row images are of initial leaf symptoms.
Last row (4 images) are leaf symptoms in later stages of development.

Plant: Tomato (Lycopersicon esculentum) (Solanaceae) Back to List
Disease/Disorder: Tomato spotted wilt (TSWV)
Causal agent: Tomato Spotted Wilt Virus (virus)
Signs:
Symptoms: Plants may be stunted and younger tissue will usually show leaf/petiole symptoms.
TSWV leaf symptoms could be similar to the later stages of 'glyphosate' injury to leaves.
Total image number: 3

Blackberry (Rubus subg. Eubatus) (Rosaceae) Back to List
Disease/Disorder: herbicide injury
Causal agent: 'glyphosate' ("RoundUp")
Signs: none
Symptoms: new leaf growth is long, narrow with a lack of green color.
Total image number: 4

Plant: Corn (Zea mays) (Poaceae) Back to List
Disease/Disorder: herbicide injury
Causal agent: 'glyphosate' ("RoundUp")
Signs: none
Symptoms: newly emerging corn with . Seedlings were just poking through the soil when herbicide was sprayed, several days after planting.
Total image number: 4

Growth regulator on Grape, Tomato (leaves and fruit), Pepper, Sunflower, Oak, Petunia, Soybean, Burning bush, Corn? (scroll down)

Grape (Vitus sp.) (Vitaceae) Back to List
Disease/Disorder: herbicide injury
Causal agent: growth regulator (e.g. 2,4-D)
Signs: none
Symptoms: leaves are disorted with veins becoming parallel. Leaf tips are elongated.
Total image number: 3

Plant: Tomato (Lycopersicon esculentum) (Solanaceae) Back to List
Disease/Disorder: herbicide injury
Causal agent: growth regulator (e.g. 2,4-D)
Signs: none
Symptoms: leaves narrow with wavy margins and elongated tips.
Total image number: 4

Plant: Tomato (Lycopersicon esculentum) (Solanaceae) Back to List
Disease/Disorder: catfacing
Causal agent: cold or growth regulator (e.g. 2,4-D)
Signs: none
Symptoms: This is an extreme case of "Catfacing". Catfacing symptoms are associated with adverse growing
conditions during blossoming; the adverse conditions result in poor pollination, which leads to irregularly shaped fruit. Catface symptoms are most often seen in large-fruited fresh market varieties (although other varieties can also be affected) and are associated with disturbances in flower production such as low temperature injury 3 weeks before flowers are mature, especially in early plantings, but also with injury from growth regulators such as 2,4-d. Pruning and high nitrogen can also aggravate the problem.
Total image number: 3

Plant: Pepper (Capsicum annuum) (Solanaceae) Back to List
Disease/Disorder: herbicide injury
Causal agent: growth regulator (e.g. 2,4-D)
Signs: none
Symptoms: leaves narrow with parallel main veins, wavy margins and elongated tips.
Total image number: 4

Sunflower (Helianthus sp.) (Asteraceae) Back to List
Disease/Disorder: herbicide injury, growth regulator injury
Causal agent: phenoxy herbicide
Signs: none
Symptoms: All the younger leaves in the sample showed symptoms of severe growth regulator
(i.e. phenoxy herbicides, e.g. 2,4-d) injury; curling, cupping, elongated tips or margins, and scalloped margins.
Total image number: 3

Plant: Oak, Pin (Quercus palustris) (Fagaceae) Back to List
Disease/Disorder: Herbicide, possible growth regulator injury
Causal agent: unknown
Signs:
Symptoms: cupping, curling, elongated tips, scalloped and/or necrotic margins of leaves; new leaves necrotic
Total image number: 4

Plant: Top Row, Petunia (Petunia hybrida) (Solanaceae) Back to List
Bottom Row, Marigold (Tagetes erecta) (Asteraceae)
Disease/Disorder: herbicide injury, growth regulator injury
Causal agent: phenoxy herbicide.
Signs: none
Symptoms: Petunia (Top Row) shows root proliferation. Marigold (Bottom Row) shows galling (this is not Crown gall).
Total image number: 8

Plant: Soybean (Glycine max) (Fabaceae) Back to List
Disease/Disorder: herbicide injury, growth regulator injury
Causal agent: phenoxy herbicide.
Signs: none
Symptoms: Actively growing leaves can cup upward along the margins.

Plant: Burning Bush, (Euonymus alatus) (Celastraceae) Back to List
Disease/Disorder: herbicide injury, growth regulator injury
Causal agent: phenoxy herbicide.
Signs: none
Symptoms: Actively growing leaves can cup upward along the margins.

Plant: Corn (Zea mays) (Poaceae) Back to List
Disease/Disorder: Crazy top
Causal agent: Sclerophthora macrospora (fungus)
Signs: none shown
Symptoms: The left-most image is of a plant that had its tassel replaced by a mass of leafy tissue.
As for the image of the very tall plant, this plant had no ears but that would not account for the plant's height; it is likely just a genetic mutation. The last two images on the right show a wrapping of the terminal leaves, which can be caused by a growth regulator.
Total image number: 4

Triazine on Tomato, Pear (Bradford)

Plant: Tomato (Lycopersicon esculentum) (Solanaceae) Back to List
Disease/Disorder: herbicide injury
Causal agent: triazine herbicide (e.g. metribuzin)
Signs: none
Symptoms: leaves narrow with wavy margins and elongated tip.
Total image number: 4

Plant: Pear 'Bradford' (Pyrus calleryana 'Bradford') (Rosaseae) Back to List
Disease/Disorder: Herbicide injury
Causal agent: Triazine herbicide (likely)
Signs:
Symptoms: A yellow/light green coloration followed by browning and death of the tissue along the margins of the leaves. This distribution of symptoms is indicative of a chemical injury absorbed by the roots. Triazine herbicides and diphenylether herbicides cause these types of symptoms. “Pramitol" (`prometon'), which is commonly used under asphalt, can cause these symptoms and is a type of triazine herbicide.
Total image number: 4

"Assure II" on Soybean

Soybean - The progression of symptoms from bleaching, reddening, then browning in blotchy to broad areas on the leaves is consistent with injury from something, possibly a solvent, in the herbicide
“Assure II”. See information from the University of Missouri at
http://www.psu.missouri.edu/soydoc/files/weed/lipidsyn.htm
and Purdue University at
http://www.btny.purdue.edu/Extension/Weeds/HerbInj/InjuryHerb2.html

Some other Mimics - problems with similar symptoms to some herbicides (scroll down).
3 examples shown below

Plant: Soybean (Glycine max) (Fabaceae) Back to List
Disease/Disorder: mutation
Causal agent: genetic
Signs:
Symptoms: This is a genetically abnormal plant. The various shades of green and yellow blotches on the leaves are variegations in the leaf chlorophyll. The general term for this phenomenon is called "Chimera".
Total image number: 2

Plant: Tobacco (Nicotiana tabacum) Back to List
Disease/Disorder: Frenching
Causal agent: metabolite of Bacillus cereus (bacterium)
Signs:
Symptoms: The image on the left is burley. The image in the middle shows an affected burley plant on the left and
an affected dark plant on the right. The image on the right shows the dark plant from the middle image, a little closer.
Total image number: 3

Plant: Chrysanthemum (cultivar 'Lisa') (Chrysanthemum sp.) (Asteraceae) Back to List
Disease/Disorder: Leaf spot
Causal agent: unknown
Signs: none
Symptoms:Leaves showed white tissue in areas on the margins and areas of white flecking located symmetrically on the leaves. A representative from Yoder Bros. said they call this the "Lisa problem". Yoder has done extensive virus/viroid testing over time and we have never been able to associate a virus or viroid. Likewise, they have done foliar and soil analyses and not been able to associate anything consistently. Also, they have never been able to associate spray injury, etc. Yoder sees this on 'Lisa' usually in the heat of the summer. The sunken white flecks are not apparent in cooler temperatures. Usually the crop grows out of it. After several years, this flecking symptom has not been considered a major problem for the chrysanthemum crop.
Total image number: 4

Plant: Tobacco (Nicotiana tabacum) Back to List
Disease/Disorder: herbicide injury
Causal agent: acetamide herbicide containing 'alachlor’, ‘metolachlor’, ‘acetochlor’, or‘dimethenamid’).
Signs:
Symptoms: The main symptom is the producion of heart-shaped leaves. In this case we believed this was a sprayer contamination issue. The injury was diagnosed by symptomatology alone.
Total image number: 4

Plant: Tobacco (Nicotiana tabacum) Back to List
Disease/Disorder: herbicide injury
Causal agent: 'picloram'
Signs:
Symptoms: Tobacco is extremely sensitive to `picloram' and small amounts from drift, contaminated equipment,
or residue in the soil will cause serious injury. Symptoms appear first on young growing leaves, but due to the
persistence of the compound, it will continue to affect the new bud leaves. `Picloram' residues may persist in the soil
and cause damage to tobacco for periods of three or more years after application.
In this case there is a question of possible contamination of the well water used to fill the floatbeds.
Total image number: 4

Plant: Tobacco (Nicotiana tabacum) Back to List
Disease/Disorder: herbicide injury
Causal agent: 'sulfentrazone' ("Spartan")
Signs:
Symptoms: The leaves show two primary symptoms:
1- areas or blotches of necrotic tissue that is due to splashing of “Spartan” up onto the leaf. It is associated with high rates of the herbicide (or overlapping), wet prone soils, and/or a heavy rain preceding the onset of symptoms by a few days. The "Spartan" label reads, under the heading "precautions": splashing of treated soil onto tobacco leaves may cause some localized burning. Use sound transplanting practices that insure treated soil will not wash or crust over tobacco plants."
2- a death (whitening) of the finer veins and a little puckering. This can be associated with the herbicide "Spartan" when taken up through the roots. The injury is associated with movement of the herbicide into the root zone due to incorporation and/or a heavy rain preceding the onset of symptoms by a few days. These symptoms are usually seen on the older leaves and little or no symptoms on the younger ones. The plants will usually grow out of the injury sustained earlier in the season. Plants taking up enough herbicide to cause injury later in the season will be stunted and the leaves that are injured are not marketable.
Total image number: 9

Plant: Tobacco (Nicotiana tabacum) Back to List
Disease/Disorder: fungicide injury
Causal agent: 'azoxystrobin' ("Quadris")
Signs:
Symptoms: Burley tobacco leaves with large spots with a water-soaked margin seen more clearly
on the bottom side of the leaves.
Image on the left is the top side of the leaves; Image on the right is the bottom side of leaves.
Total image number: 2

Plant: Squash, Zucchini (Nicotiana tabacum) Back to List
Disease/Disorder: fungicide injury
Causal agent: 'clomazone' ("Command")
Signs: none
Symptoms: 'Clomazone' is a pigment inhibitor which is primarily translocated in the xylem tissue. It is one of the most soil-persistent herbicides used on crops. Leaf tissue usually recovers but if there is high heat an intense sunshine the white tissue may sustain some injury and become brown and necrotic.