Key to Help Determine Cause of Soybean Abnormality

You selected "Vegetative (V5-R1).". Now select which of the following descriptions best fits your observation.


III.A. Plants wilted or dead
III.B. Plants have damage to leaves and/or stems
III.C. Plants show discoloration or abnormal growth of leaves and/or stems; plants may appear stunted
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You have selected "III.A. Plants wilted or dead." Now select which of the following descriptions best fits your observation.


III.A.1. Leaves are discolored or wilted
 III.A.2. Stems show discoloration and/or fungal structures
 III.A.3. Plants broken off neatly at ground level
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III.A.3.Possible causes:
three-cornered alfalfa hopper text descriptionreturn to the beginning
lesser cornstalk borer text descriptionreturn to the beginning
surface applied pendimethalin text descriptionreturn to the beginning
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You have selected &III.A.1.Leaves are discolored or wilted." Now select which of the following descriptions best fits your observation.


III.A.1.a. Leaves with narrow silver to light brown areas along major veins or over the whole leaf
 III.A.1.b. Leaves yellow, may wilt; some plants may die
 III.A.1.c. Leaves wilted, dead, or dropped
 III.A.1.d. Leaves yellow, speckled; plants may be stunted with presence of webbing and/or mites underside of leaves
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III.A.1.a. Possible cause:
thrips text descriptionreturn to the beginning

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III.A.1.b. Possible causes:
grape colaspis larvae text descriptionreturn to the beginning
white grubs text descriptionreturn to the beginning
wireworms text descriptionreturn to the beginning
lesser cornstalk borer text descriptionreturn to the beginning
Dectes stem borer text descriptionreturn to the beginning
soybean aphid text descriptionreturn to the beginning
glyphosate text descriptionreturn to the beginning
Phytophthora root and stem rot text descriptionreturn to the beginning
soybean cyst nematode text descriptionreturn to the beginning
Rhizoctonia root rot text descriptionreturn to the beginning
Fusarium root rot text descriptionreturn to the beginning
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III.A.1.c. Possible causes:
lightning text descriptionreturn to the beginning
lesser cornstalk borer text descriptionreturn to the beginning
white grubs text descriptionreturn to the beginning
grape colaspis larvae text descriptionreturn to the beginning
Dectes stem borer text descriptionreturn to the beginning
soybean aphid text descriptionreturn to the beginning
wireworms text descriptionreturn to the beginning
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III.A.1.d. Possible cause:
spider mites text descriptionreturn to the beginning
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You have selected &III.A.2. Stems show discoloration and/or fungal structures." Now select which of the following descriptions best fits your observation.


III.A.2.a. White fungal growth and sclerotia (mustard seed-like structures) present
 III.A.2.b. White fungal growth and sclerotia (large, black, irregular structures) inside stem
 III.A.2.c. Discolored stems with reddish fruiting bodies present
 III.A.2.d. Lower stem discolored
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III.A.2.a. Possible cause:
southern blight text descriptionreturn to the beginning

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III.A.2.b. Possible cause:
Sclerotinia stem rot text descriptionreturn to the beginning

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III.A.2.c. Possible cause:
red crown rot text descriptionreturn to the beginning

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III.A.2.d. Possible causes:
Phytophthora root and stem rot text descriptionreturn to the beginning
Rhizoctonia root rot text descriptionreturn to the beginning
charcoal rot text descriptionreturn to the beginning

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You have selected &III.B. Plants have damage to leaves and/or stems." Now select which plant part is affected.


III.B.1. Leaf damage
III.B.2. Stem damage
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You have selected &III.B.1. Leaf damage." Now select which of the following descriptions best fits your observation.


III.B.1.a. Leaves torn
 III.B.1.b. Leaves show evidence of insect feeding
 III.B.1.c. Leaves chewed off or removed
 III.B.1.d. Leaf petioles collapsed and leaves hanging from point of collapse
 III.B.1.e. Leaves wrinkled and/or disfigured and plants may be stunted
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III.B.1.a. Possible cause:
hail damage text descriptionreturn to the beginning

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III.B.1.b. Possible causes:
grasshoppers text descriptionreturn to the beginning
soybean looper text descriptionreturn to the beginning
bean leaf beetle text descriptionreturn to the beginning
green clover worm text descriptionreturn to the beginning
blister beetles text descriptionreturn to the beginning
cutworms text descriptionreturn to the beginning
Japanese beetle text descriptionreturn to the beginning
Mexican bean beetle text descriptionreturn to the beginning
fall armyworm text descriptionreturn to the beginning

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III.B.1.c. Possible cause:
wildlife or livestock feeding text descriptionreturn to the beginning

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III.B.1.d. Possible cause:
three-cornered alfalfa hopper text descriptionreturn to the beginning

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III.B.1.e. Possible causes:
growth regulators text descriptionreturn to the beginning
cell membrane disruptors text descriptionreturn to the beginning

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You have selected &III.B.2.Stem damage." Now select which of the following descriptions best fits your observation.


III.B.2.a. Terminals of stems fed on and hanging from plant
 III.B.2.b. Stems girdled or have a dark ring at or above soil line with possible adventitious root development
 III.B.2.c. Stems fed on at or below soil line
 III.B.2.d. Stems tunneled into at or below soil line
 III.B.2.e. Stems snap off at base
 III.B.2.f. Stems hollowed and contain white, lobed beetle larva
 III.B.2.g. Small sand-covered tube attached to stem at soil line
 III.B.2.h. Stems bent and/or callus growth present
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III.B.2.a. Possible causes:
corn earworm text descriptionreturn to the beginning
cutworms text descriptionreturn to the beginning
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III.B.2.b. Possible causes:
three-cornered alfalfa hopper text descriptionreturn to the beginning
surface applied pendimethalin text descriptionreturn to the beginning
paraquat drift text descriptionreturn to the beginning
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III.B.2.c. Possible causes:
lesser cornstalk borer text descriptionreturn to the beginning
cutworms text descriptionreturn to the beginning
wireworms text descriptionreturn to the beginning
grape colaspis larvae text descriptionreturn to the beginning
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III.B.2.d. Possible cause:
lesser cornstalk borer text descriptionreturn to the beginning

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III.B.2.e. Possible causes:
three-cornered alfalfa hopper text descriptionreturn to the beginning
lesser cornstalk borer text descriptionreturn to the beginning
surface applied pendimethalin text descriptionreturn to the beginning
hail damage text descriptionreturn to the beginning
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III.B.2.f. Possible cause:
Dectes stem borer text descriptionreturn to the beginning

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III.B.2.g. Possible cause:
lesser cornstalk borer text descriptionreturn to the beginning

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III.B.2.h. Possible cause:
growth regulators text descriptionreturn to the beginning

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You have selected &III.C. Plants show discoloration or abnormal growth of leaves; plants may appear stunted." Now select which of the following descriptions best fits your observation.


III.C.1. Leaves show spots with possible later necrotic areas
 III.C.2. Leaves show spots or ragged burned appearance
 III.C.3. Leaves show yellowing; some yellowing may occur in interveinal pattern or from leaf margins
 III.C.4. Leaves crinkled and/or disfigured and plants may or may not be stunted
 III.C.5. Root show stunting or abnormal growth
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You have selected &III.C.1. Leaves show spots with possible later necrotic areas." Now select which of the following descriptions best fits your observation.


III.C.1.a. Small, yellow to brown spots with possible later necrotic area
 III.C.1.b. Leaves have lesions with light-colored centers and dark margins; when severe, leaves may have a ragged or tattered appearance
 III.C.1.c. Brown spots and/or yellowing on lower leaves
 III.C.1.d. Top and/or underside of leaves appear silvered or speckled; plants may be stunted
 III.C.1.e Yellow to brown spots on upper leaf surface and gray to purple fungal growth on underside of leaf
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III.C.1.a. Possible cause:
bacterial pustule text descriptionreturn to the beginning

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III.C.1.b. Possible cause:
frogeye leaf spot text descriptionreturn to the beginning

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III.C.1.c. Possible cause:
Septoria brown spot text descriptionreturn to the beginning

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III.C.1.d. Possible causes:
thrips (look for silver streaks) text descriptionreturn to the beginning
spider mites text descriptionreturn to the beginning

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III.C.1.e Possible cause:
downy mildew text descriptionreturn to the beginning

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You have selected &III.C.2. Leaves show spots or ragged burned appearance." Now select which of the following descriptions best fits your observation.


III.C.2.a. Leaves have dead, ragged appearance after beating wind and rain
 III.C.2.b. Leaves are speckled or burned; new growth is generally unaffected
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III.C.2.a. Possible cause:
bacterial blight text descriptionreturn to the beginning

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III.C.2.b. Possible causes:
non-mobile photosynthesis inhibitors text descriptionreturn to the beginning
cell membrane disruptors text descriptionreturn to the beginning
glufosinate text descriptionreturn to the beginning
sunburn text descriptionreturn to the beginning
air pollution text descriptionreturn to the beginning
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You have selected &III.C.3. Leaves show yellowing; some yellowing may occur in interveinal pattern or from leaf margins." Now select which of the following descriptions best fits your observation.


III.C.3.a. Yellowing along leaf margins; followed by browning and later necrosis; no leaf curl
 III.C.3.b. Narrow yellowing along leaf margins and leaf curling
 III.C.3.c. Interveinal yellowing of young leaves; veins remain green
 III.C.3.d. Interveinal yellowing
 III.C.3.e. Yellowing of old and young leaves
 III.C.3.f. Leaves yellow and some plants are stunted; there is evidence of insect damage to roots and/or stem
III.C.3.g. Possible yellowing and some distortion of young leaves; plants may be stunted with shortened internodes; may or may not have black veins on back of leaf
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III.C.3.a. Possible causes:
potassium deficiency text descriptionreturn to the beginning
boron toxicity text descriptionreturn to the beginning
zinc deficiency text descriptionreturn to the beginning
non-mobile photosynthesis inhibitors text descriptionreturn to the beginning
Rhizoctonia root rot text descriptionreturn to the beginning
soybean cyst nematode text descriptionreturn to the beginning
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III.C.3.b. Possible causes:
potato leafhopper text descriptionreturn to the beginning
growth regulators text descriptionreturn to the beginning
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III.C.3.c. Possible causes:
manganese deficiency text descriptionreturn to the beginning
iron deficiency text descriptionreturn to the beginning
magnesium deficiency text descriptionreturn to the beginning
cell membrane disruptors text descriptionreturn to the beginning
glyphosate text descriptionreturn to the beginning
ALS inhibitors text descriptionreturn to the beginning
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III.C.3.d. Possible causes:
norflurazon text descriptionreturn to the beginning
quizalofop text descriptionreturn to the beginning
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III.C.3.e. Possible causes:
sulfur deficiency text descriptionreturn to the beginning
nitrogen deficiency text descriptionreturn to the beginning
molybdenum deficiency text description
zinc deficiency text descriptionreturn to the beginning
magnesium deficiency text descriptionreturn to the beginning
saturated soil text description
lance nematode text descriptionreturn to the beginning
soybean cyst nematode text descriptionreturn to the beginning
root-knot nematode text descriptionreturn to the beginning
Phytophthora root and stem rot text descriptionreturn to the beginning
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III.C.3.f. Possible causes:
white grubs text descriptionreturn to the beginning
grape colaspis larvae text descriptionreturn to the beginning
wireworms text descriptionreturn to the beginning
lesser cornstalk borer text descriptionreturn to the beginning
soybean aphid text descriptionreturn to the beginning
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III.C.3.g. Possible causes:
ALS inhibitors text descriptionreturn to the beginning
glyphosate text descriptionreturn to the beginning
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You have selected &III.C.4. Leaves crinkled and/or disfigured and plants may or may not be stunted." Now select which of the following descriptions best fits your observation.


III.C.4.a. Leaves crinkled and/or disfigured
 III.C.4.b. Leaves crinkled and/or distorted with possible plant stunting
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III.C.4.a. Possible causes:
growth regulators text descriptionreturn to the beginning
cell membrane disruptors text descriptionreturn to the beginning
soybean mosaic text descriptionreturn to the beginning
bean pod mottle text descriptionreturn to the beginning
bean yellow mosaic text descriptionreturn to the beginning
bud blight text descriptionreturn to the beginning
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III.C.4.b. Possible causes:
growth regulators text descriptionreturn to the beginning
manganese toxicity text description
boron toxicity text descriptionreturn to the beginning
zinc deficiency text descriptionreturn to the beginning
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You have selected &III.C.5. Root show stunting or abnormal growth." Now select which of the following descriptions best fits your observation.


III.C.5.a. Little or no nodule development
 III.C.5.b Little or no secondary root development
 III.C.5.c. Proliferation of secondary roots
 III.C.5.d. Root galls formed
 III.C.5.e. Small, yellow to white, lemon-shaped females or cysts present on roots
 III.C.5.f. Irregular or L-shaped roots
 III.C.5.g. Holes in nodules
 III.C.5.h. Roots with evidence of insect feeding
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III.C.5.a. Possible causes:
lance nematode text descriptionreturn to the beginning
soybean cyst nematode text descriptionreturn to the beginning
sting nematode text descriptionreturn to the beginning
acid soil pH text description
molybdenum deficiency text description
nitrogen deficiency text descriptionreturn to the beginning
soil compaction text descriptionreturn to the beginning
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III.C.5.b Possible causes:
lance nematode text descriptionreturn to the beginning
reniform nematode text descriptionreturn to the beginning
sting nematode text descriptionreturn to the beginning
root lesion nematode text descriptionreturn to the beginning
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III.C.5.c. Possible causes:
root-knot nematode text descriptionreturn to the beginning
lance nematode text descriptionreturn to the beginning
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III.C.5.d. Possible cause:
root-knot nematode text descriptionreturn to the beginning
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III.C.5.e. Possible cause:
soybean cyst nematode text descriptionreturn to the beginning

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III.C.5.f. Possible cause:
soil compaction text descriptionreturn to the beginning

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III.C.5.g. Possible cause:
soybean nodule fly

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III.C.5.h. Possible cause of this abnormality:
wireworms text descriptionreturn to the beginning
white grubs text descriptionreturn to the beginning
grape colaspis larvae text descriptionreturn to the beginning
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