Key to Help Determine Cause of Soybean Abnormality

You selected "Reproductive IV (R1 through harvest)". Now select which of the following descriptions best fits your observation.


IV.A. Plants wilted or dead
IV.B. Flowers not present, damaged, or eaten off
IV.C. Pod damage or loss
IV.D. Plants have physical damage to leaves and/or stems
IV.E. Plants have discoloration and/or stunting of leaves and/or stems
IV.F. Plants stunted with possible abnormal growth
IV.G. Plants in spots in field remain green past maturity of remainder of field
IV.H. Seed discolored or damaged
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You selected "IV.A. Plants wilted or dead." Now select which of the following descriptions best fits your observation.

IV.A.1. Plants are dead with stems or roots showing no evidence of disease or nematode damage
IV.A.2. Plants are dead, but stems and/or roots show evidence of disease or nematode damage
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You selected "IV.A.1. Plants are dead with stems or roots showing no evidence of disease or nematode damage." Now select which of the following descriptions best fits your observation.

IV.A.1.a. Plants broken off at ground level; callus tissue and adventitious roots present
IV.A.1.b. Scorched-looking, dead areas in field
IV.A.1.c. Circular pattern of dead plants in field
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IV.A.1.a. 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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IV.A.1.b. Possible cause:
spider mites text descriptionreturn to the beginning

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IV.A.1.c. Possible cause:
lightning text descriptionreturn to the beginning

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You selected "IV.A.2. Plants are dead, but stems and/or roots show evidence of disease or nematode damage." Now select which of the following descriptions best fits your observation.

IV.A.2.a. White fungal growth and mustard seed-like structures on lower stem
IV.A.2.b. White fungal growth and sclerotia (large, black, irregular structures inside and outside the stem)
IV.A.2.c. Discolored stem with minute, black fruiting structures present
IV.A.2.d. Discolored stem with reddish fruiting structures present
IV.A.2.e. Discolored stem without fruiting structures but with cankers present near stem nodes
IV.A.2.f. Dark brown to purple brown discoloration of stem extending from soil line upwards
IV.A.2.g. Roots with galls, cysts, root proliferation, or stubbiness
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IV.A.2.a. Possible cause:
southern blight text descriptionreturn to the beginning

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

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IV.A.2.c. Possible cause:
charcoal rot text descriptionreturn to the beginning

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IV.A.2.d. Possible cause:
red crown rot text descriptionreturn to the beginning

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IV.A.2.e. Possible cause:
stem canker text descriptionreturn to the beginning

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IV.A.2.f. Possible cause:
Phytophthora root and stem rot text descriptionreturn to the beginning

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IV.A.2.g. Possible causes:
lance nematode text descriptionreturn to the beginning
soybean cyst nematode text descriptionreturn to the beginning
root-knot nematode text descriptionreturn to the beginning
sting nematode text descriptionreturn to the beginning

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You selected "IV.B. Flowers not present, damaged, or eaten off." Now select which of the following descriptions best fits your observation.

IV.B.1. Flowers fed on or eaten off
IV.B.2. Flowers fallen off or not present
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IV.B.1. Possible causes:
corn earworm text descriptionreturn to the beginning
bean leaf beetle text descriptionreturn to the beginning

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IV.B.2. Possible causes:
drought damage text descriptionreturn to the beginning
boron deficiency text description
zinc deficiency text descriptionreturn to the beginning

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You selected "IV.C. Pod damage or loss." Now select which of the following descriptions best fits your observation.

IV.C.1. Pods show evidence of insect damage
IV.C.2. Pods are discolored, stunted, or shriveled
IV.C.3. Pods are split along midline
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IV.C.3. Possible cause:
pods too small for developing beans (can occur during season with alternating dry and wet conditions)

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You selected "IV.C.1. Pods show evidence of insect damage." Now select which of the following descriptions best fits your observation.

IV.C.1.a. Pods with evidence of feeding into seed cavity
IV.C.1.b. Pods with superficial feeding, rarely reaching seed cavity
IV.C.1.c. Pods cut off plant and lying on the ground
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IV.C.1.a. Possible causes:
corn earworm text descriptionreturn to the beginning
grasshoppers text descriptionreturn to the beginning
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IV.C.1.b. Possible causes:
bean leaf beetle text descriptionreturn to the beginning
velvetbean catepillar text descriptionreturn to the beginning
Mexican bean beetle text descriptionreturn to the beginning
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IV.C.1.c. Possible cause:
velvetbean catepillar (following heavy defoliation) text descriptionreturn to the beginning

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You selected "IV.C.2. Pods are discolored, stunted, or shriveled." Now select which of the following descriptions best fits your observation.

IV.C.2.a. Pods with fungal fruiting bodies present
IV.C.2.b. Pods not cut off, but have fallen off plant, usually young pods less than 1/2 inch long
IV.C.2.c. Pods shriveled with one or more seeds aborted
IV.C.2.d. Pods are hardened, knotty, with spots; seeds are smaller than normal and may be shriveled
IV.C.2.e. Pods abnormal, distorted, small with usually one or no seeds per pod
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IV.C.2.a. Possible causes:
pod and stem blight text descriptionreturn to the beginning
anthracnose text descriptionreturn to the beginning
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IV.C.2.b. Possible causes:
drought damage text descriptionreturn to the beginning
boron deficiency text description
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IV.C.2.c. Possible causes:
stink bugs text descriptionreturn to the beginning
pod and stem blight text descriptionreturn to the beginning
anthracnose text descriptionreturn to the beginning
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IV.C.2.d. Possible cause:
stink bugs text descriptionreturn to the beginning

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IV.C.2.e. Possible cause:
bud blight text descriptionreturn to the beginning

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You selected "IV.D. Plants have physical damage to leaves and/or stems." Now select which of the following descriptions best fits your observation.

IV.D.1. Leaves show evidence of insect feeding
IV.D.2. Leaves hanging down due to shriveled, collapsed petioles or stems
IV.D.3. Terminal of stems hang from plant due to insect feeding injury
IV.D.4. Plants snap off or lodge when physically touched or blown over during wind and/or heavy rains
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IV.D.2. Possible cause:
three-cornered alfalfa hopper text descriptionreturn to the beginning

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IV.D.3. Possible cause:
corn earworm text descriptionreturn to the beginning

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IV.D.4. 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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You selected "IV.D.1. Leaves show evidence of insect feeding.>" Now select which of the following descriptions best fits your observation.

IV.D.1.a. Leaves skeletonized or lacy in appearance
IV.D.1.b. Holes eaten in leaves or feeding occurs from leaf margins

IV.D.1.c. Leaves with mottled yellow appearance; some leaves may appear scorched

IV.D.1.d. Leaf tips and upper leaf margins yellow; sometimes with cupping of leaf margins

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IV.D.1.a. Possible causes:
Mexican bean beetle text descriptionreturn to the beginning
Japanese beetle text descriptionreturn to the beginning
green cloverworm text descriptionreturn to the beginning
soybean looper text descriptionreturn to the beginning
velvetbean catepillar text descriptionreturn to the beginning
yellow wooly-bear text description
blister beetle text descriptionreturn to the beginning
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IV.D.1.b Possible causes:
grasshoppers text descriptionreturn to the beginning
green cloverworm text descriptionreturn to the beginning
soybean looper text descriptionreturn to the beginning
velvetbean catepillar text descriptionreturn to the beginning
yellow wooly-bear text description
blister beetle text descriptionreturn to the beginning
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IV.D.1.c Possible causes:
spider mites text descriptionreturn to the beginning
glyphosate text descriptionreturn to the beginning
ALS inhibitors text descriptionreturn to the beginning
glufosinate text descriptionreturn to the beginning
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IV.D.1.d Possible causes:
potato leafhopper text descriptionreturn to the beginning
soybean aphid text descriptionreturn to the beginning
growth regulators text descriptionreturn to the beginning
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You selected "IV.E. Plants have discoloration and/or stunting of leaves and/or stems." Now select which of the following descriptions best fits your observation.

IV.E.1. Upper leaves with interveinal chlorosis
IV.E.2. Stems blighted with fungal structures present; observed more prominently near maturity
IV.E.3. Cankers from lower to mid sections of main stem, mostly near the axils of branches
IV.E.4. Leaves discolored, spotted and/or blighted
IV.E.5. Leaves and/or stems covered with white powdery mold
IV.E.6. Premature leaf yellowing with silver-gray discoloration of lower stem
IV.E.7. Holes in nodules
IV.E.8. Plants may be wilting or dying with stems tunneled
IV.E.9 Roots fed on or cut off
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IV.E.1. Possible causes:
red crown rot text descriptionreturn to the beginning
stem canker text descriptionreturn to the beginning
brown stem rot text descriptionreturn to the beginning
Phytophthora root and stem rot text descriptionreturn to the beginning
sudden death syndrome text descriptionreturn to the beginning
glyphosate text descriptionreturn to the beginning
ALS inhibitors text descriptionreturn to the beginning

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IV.E.2. Possible causes:
pod and stem blight text descriptionreturn to the beginning
anthracnose text descriptionreturn to the beginning
red crown rot text descriptionreturn to the beginning
southern blight text descriptionreturn to the beginning
Sclerotinia stem rot text descriptionreturn to the beginning
charcoal rot text descriptionreturn to the beginning

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IV.E.3. Possible cause:
stem canker text descriptionreturn to the beginning

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IV.E.4. Possible causes:
frogeye leaf spot text descriptionreturn to the beginning
bacterial blight text descriptionreturn to the beginning
aerial blight text descriptionreturn to the beginning
downy mildew text descriptionreturn to the beginning
Septoria brown spot text descriptionreturn to the beginning
Cercospora leaf blight text descriptionreturn to the beginning
brown stem rot text descriptionreturn to the beginning
charcoal rot text descriptionreturn to the beginning
sunburn text descriptionreturn to the beginning
air pollution text descriptionreturn to the beginning

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IV.E.5. Possible cause:
powdery mildew text descriptionreturn to the beginning

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IV.E.6. Possible cause:
charcoal rot text descriptionreturn to the beginning

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IV.E.7. Possible cause:
soybean nodule fly

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IV.E.8. Possible cause of this abnormality:
Dectes stem borer text descriptionreturn to the beginning

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IV.E.9. Possible cause of this abnormality:
grape colaspis larvae text descriptionreturn to the beginning
white grubs text descriptionreturn to the beginning
wireworms text descriptionreturn to the beginning

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You selected "IV.F. Plants stunted with possible abnormal growth." Now select which of the following descriptions best fits your observation.

VI.F.1. Leaves crinkled, mottled, or distorted
VI.F.2. Leaves yellowed; roots with galls, cysts, root proliferation, or stubbiness
VI.F.3. Leaves yellowed; some plants stunted (roots and/or stems may also be damaged)
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VI.F.1. Possible causes:
growth regulators text descriptionreturn to the beginning
cell membrane disruptors text descriptionreturn to the beginning
ALS inhibitors text descriptionreturn to the beginning
soybean mosaic text descriptionreturn to the beginning
bean pod mottle text descriptionreturn to the beginning
peanut mottle text descriptionreturn to the beginning
bean yellow mosaic text descriptionreturn to the beginning
bud blight text descriptionreturn to the beginning
zinc deficiency text descriptionreturn to the beginning
manganese toxicity text description
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VI.F.2. Possible causes:
root-knot nematode text descriptionreturn to the beginning
soybean cyst nematode text descriptionreturn to the beginning
lance nematode text descriptionreturn to the beginning
sting nematode text descriptionreturn to the beginning
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VI.F.3. Possible causes:
white grubs text descriptionreturn to the beginning
Dectes stem borer text descriptionreturn to the beginning
grape colaspis larvae text descriptionreturn to the beginning
glyphosate text descriptionreturn to the beginning
ALS inhibitors text descriptionreturn to the beginning
growth regulators text descriptionreturn to the beginning
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You selected "IV.G. Plants in spots in field remain green past maturity of remainder of field." Now select which of the following descriptions best fits your observation.

IV.G.1. Few if any pods are present; otherwise affected plant has normal green appearance
IV.G.2. Some leaves are crinkled
IV.G.3. Normal pods with mature color present but stems and petioles remain green after maturity
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IV.G.1. Possible causes:
stink bugs text descriptionreturn to the beginning
bud blight text descriptionreturn to the beginning
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IV.G.2. Possible cause:
growth regulators text descriptionreturn to the beginning
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IV.G.3. Possible causes:
bean pod mottle text descriptionreturn to the beginning
soybean mosaic text descriptionreturn to the beginning
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You selected "IV.H. Seed discolored or damaged." Now select which of the following descriptions best fits your observation.

IV.H.1. Brown or black streaks coming from hilum
IV.H.2. Seeds show purple color patterns at maturity
IV.H.3. Seeds are moldy, dark, or deformed
IV.H.4. Seed coats are split
IV.H.5. Seeds are abnormally small and shriveled
IV.H.6. Seeds are orange to brick red or light to dark brown; as damage increases, seeds are shriveled
IV.H.7. Green seeds, some often small and shriveled
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IV.H.1. Possible causes:
soybean mosaic text descriptionreturn to the beginning
bean pod mottle text descriptionreturn to the beginning
genetic

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IV.H.2. Possible causes:
purple seed stain text descriptionreturn to the beginning
stain from juices of black nightshade berries

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IV.H.3. Possible causes:
pod and stem blight text descriptionreturn to the beginning
Cercospora leaf blight text descriptionreturn to the beginning
anthracnose text descriptionreturn to the beginning
downy mildew text descriptionreturn to the beginning

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IV.H.4. Possible cause:
excessive rainfall during pod-fill following a drought

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IV.H.5. Possible causes:
stink bugs text descriptionreturn to the beginning
soybean aphid text descriptionreturn to the beginning
charcoal rot text descriptionreturn to the beginning
brown stem rot text descriptionreturn to the beginning
stem canker text descriptionreturn to the beginning
sudden death syndrome text descriptionreturn to the beginning
bud blight text descriptionreturn to the beginning
soybean mosaic text descriptionreturn to the beginning
bean pod mottle text descriptionreturn to the beginning
drought damage text descriptionreturn to the beginning

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IV.H.6. Possible cause:
stink bugs text descriptionreturn to the beginning

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IV.H.7. Possible causes:
frost damage text descriptionreturn to the beginning
heat and/or droght damage text descriptionreturn to the beginning

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