Small Grains:Key

KEY TO WHEAT PESTS AND NUTRITIONAL DISORDERS

Seed

Seed disorders are limited to disorders while in the ground and not to potential disorders inherent in the seed.

BLUE/GRAY

Storage molds

Embryo of seed darkened; musty odor; green, blue, or yellow mycelial growth on seeds incubated under moist conditions

BROWN/BLACK

Black point

Embryo end of kernels dark brown to black

DARK

Storage molds

Embryo of seed darkened; musty odor; green, blue, or yellow mycelial growth on seeds incubated under moist conditions

GREEN

Storage molds

Embryo of seed darkened; musty odor; green, blue, or yellow mycelial growth on seeds incubated under moist conditions

YELLOW

Storage molds

Embryo of seed darkened; musty odor; green, blue, or yellow mycelial growth on seeds incubated under moist conditions

No Distinct Discoloration

Dwarf bunt

Plants are severely stunted, with bunt balls replacing the seed; characteristic fishy odor when bunt balls are broken open

Seedling

BROWN

Sclerotium Wilt (Southern Blight)

Damping off of seedlings; white, fluffy fungal mycelia on tissue surfaces; later the plant may have rotted culms, crowns, and roots and eventually die; white sclerotia can be found on the crown tissues, culms, or near the soil surface and later turn brown

Wireworms (various species)

Wireworms are long, smooth and vary from shades of cream to brown; larvae may attack wheat soon after planting; common sign of attack is the wilting and/or dying of a number of adjacent plants; stems of affected seedlings will be chewed above the seed

TAN/YELLOW/BROWN

Tan Spot (Yellow Leaf Spot or Blotch)

Lesions develop on plant parts that begin as tan to brown flecks and develop into large tan blotches with a yellow or chlorotic margin and a dark brown to black spot in the center; heavy infestation will cause the death of the entire plant or plant parts

WHITE

Cereal Cyst Nematode

Roots develop frequent branches and cysts; cysts are off-white when young, turning dark brown as they age; seedlings are most affected and are often invaded by soil-borne pathogens, especially root and crown rots

Sclerotium Wilt (Southern Blight)

Damping off of seedlings; white, fluffy fungal mycelia on tissue surfaces; later the plant may have rotted culms, crowns, and roots and eventually die; white sclerotia can be found on the crown tissues, culms, or near the soil surface and later turn brown

YELLOW/BROWN

Alternaria Leaf Blight

Small, chlorotic, oval- or elliptical- lesions appear on all plant parts, becoming large irregular blotches; chlorotic borders may turn light to dark brown in color infection usually start on the lower leaves

No Distinct Discoloration

Hybrid Necrosis

Dwarf clumping

Moisture Stress

Young plants will be stunted and have reduced tillering and root development; leaves may curl and roll during the hottest part of the day; development of spikelets and florets may be reduced; grain may shrivel; death may occur in plants needing water

Slugs and Snails (various species)

Slugs and snails can feed on the endosperm of germinating seed, bite seedlings off at ground level, and graze older plants, chewing longitudinal stripes on the leaves causing them to become frayed

Root

BROWN

Aluminum Toxicity

High concentration of aluminum give roots a stubby appearance and brown color; leaves are small and internodes are shortened and thickened; leaf tips may die and old leaves may become yellow and brittle

Common Root Rot, Foot Rot, and Crown Rot

Darkening or browning of the root, crown and basal culm tissues; individual plants or groups of plants may lodge; white spikes often are visible just prior to normal physiological maturity

Sharp Eyespot and Rhizoctonia Root Rot

Dark brown lesions with pale, straw-colored centers develop on basal leaf sheaths; mycelia often are present in the centers of lesions and are easily removed by rubbing; roots can become brown and reduced in number; disease can cause stunting

White Grubs (various species)

Roots may be partially or completely severed causing wilting and dying; when fully grown, the largest of these larvae may be several centimeters long and nearly one centimeter thick; the larvae have three pairs of legs on their thorax

DARK

Take-all; Common Root Rot; Foot Rot; Crown Rot

Darkish rots and lesions on the roots or crown

WHITE

Cereal Cyst Nematode

Roots develop frequent branches and cysts; cysts are off-white when young, turning dark brown as they age; seedlings are most affected and are often invaded by soil-borne pathogens, especially root and crown rots

Common Root Rot; Foot Rot; Crown Rot; Sclerotium Wilt

White mycelium on the roots or crown

Take-All

This fungus causes rotting of the roots and lower stems causing them to turn shiny black; coarse, black runner hyphae are conspicuous on roots; severe infestation is indicated by stunted plants with whitened stems and spikes

WHITE/BROWN

Armyworms; Cutworms; Stalk Borers; White Grubs; Wireworms

Attached white or brown galls, cysts or nodules on roots

No Distinct Discoloration

Armyworms; Cutworms; Stalk Borers; White Grubs; Wireworms

Severed or chewed roots

Barley Yellow Dwarf

Affected plants show a yellowing or reddening of leaves, stunting, and upright posture of thickened stiff leaves, reduced root growth, delayed (or no) heading, and a reduction of yield; head affected tend to remain erect and become black and discolored

Cereal Cyst Nematode; Root Knot Nematode; Aluminum Toxicity

Deformed, knotted or stubby roots

Moisture Stress

Young plants will be stunted and have reduced tillering and root development; leaves may curl and roll during the hottest part of the day; development of spikelets and florets may be reduced; grain may shrivel; death may occur in plants needing water

Root Knot Nematode

Small knots or galls grow near the tips of the roots; infested plants are stunted and chlorotic; roots may excessively branch

Root Knot Nematode

Small knots or galls grow near the tips of the roots; infested plants are stunted and chlorotic; roots may excessively branch

Crown

BLACK

Sclerotium Wilt

White to black fruiting bodies on the crown

Take-all

Shiny black crown node

BROWN

Sclerotium Wilt (Southern Blight)

Damping off of seedlings; white, fluffy fungal mycelia on tissue surfaces; later the plant may have rotted culms, crowns, and roots and eventually die; white sclerotia can be found on the crown tissues, culms, or near the soil surface and later turn brown

Cereal Cyst Nematode

Roots develop frequent branches and cysts; cysts are off-white when young, turning dark brown as they age; seedlings are most affected and are often invaded by soil-borne pathogens, especially root and crown rots

DARK

Take-all; Common Root Rot; Foot Rot; Crown Rot

Darkish rots and lesions on roots or crown

WHITE

Common Root Rot, Foot Rot, and Crown Rot

Darkening or browning of the root, crown and basal culm tissues; individual plants or groups of plants may lodge; white spikes often are visible just prior to normal physiological maturity

Common Root Rot; Foot Rot; Crown Rot; Sclerotium Wilt

White mycelium on the roots or crown

Sclerotium Wilt

White to black fruiting bodies on the crown

YELLOW/BROWN

Alternaria Leaf Blight

Small, chlorotic, oval- or elliptical- lesions appear on all plant parts, becoming large irregular blotches; chlorotic borders may turn light to dark brown in color infection usually start on the lower leaves

Stem

BLACK

Leaf Rust (Brown Rust); Stem Rust (Black Rust); Stripe Rust (Yellow Rust)

Raised pustules with yellow, orange, brown or black spores on the stems

Septoria Diseases; Septoria tritici, Septoria nodorum, Septoria avanae f.sp. triticea

Oval to elongated spots or lesions can appear on all aboveground plant parts; centers of lesions are pale to straw-colored, necrotic, and contain numerous small black dots; heavy infestations can cause death; identification is difficult

Septoria Tritici Blotch; Black Chaff; Bacterial Stripe; Physiological Leaf Spot

Brown to black spots or stripes on stems

Take-all

Black, shiny fungal tissue beneath leaf sheath on the stem

BROWN

Eyespot (Strawbreaker)

Eye-shaped, elliptical lesions develop on the internodes of the lower stem and are bordered by dark brown to greenish brown rings with straw-colored centers, frequently developing on the leaf sheath at soil level

Eyespot; Sharp Eyespot with Rhizoctonia Root Rot

Brown, elongated distinct eye-shaped lesions on stems

Leaf Rust (Brown Rust); Stem Rust (Black Rust); Stripe Rust (Yellow Rust)

Raised pustules with yellow, orange, brown or black spores on the stems

Seed Gall Nematode (Wheat Nematode or Ear Cockle)

Distorted leaves and stems appear prior to heading; dark brown galls are formed in the florets upon maturity, replacing the kernels; masses of motile larvae are present within the galls and become active after the galls have been moistened

Septoria Tritici Blotch; Black Chaff; Bacterial Stripe; Physiological Leaf Spot

Brown to black spots or stripes on stems

Stem Rust (Black Rust)

Dark reddish brown pustules on the leaves, stems and spikes; pustules may be separate or coalesce together with heavy infestations; before the spore masses break through the epidermis the infection sites may feel rough and take on a ragged appearance

Wireworms (various species)

Wireworms are long, smooth and vary from shades of cream to brown; larvae may attack wheat soon after planting; common sign of attack is the wilting and/or dying of a number of adjacent plants; stems of affected seedlings will be chewed above the seed

Tan Spot (Yellow Leaf Spot or Blotch)

Lesions develop on plant parts that begin as tan to brown flecks and develop into large tan blotches with a yellow or chlorotic margin and a dark brown to black spot in the center; heavy infestation will cause the death of the entire plant or plant parts

BROWN/BLACK/PURPLE

Melanism and Brown Necrosis (False Black Chaff)

Brownish black to dark purple spots, streaks, or blotches appear on the leaf sheaths, stems, and/or glumes; dark brown pigmentation usually develops on the glumes and peduncles

GRAY

Powdery Mildew

Superficial white, pinkish, or gray fungal tissue on the stem

GRAY

Powdery Mildew; Scab

Superficial white, pinkish or gray fungal tissue on the head

GREEN

Eyespot (Strawbreaker)

Eye-shaped, elliptical lesions develop on the internodes of the lower stem and are bordered by dark brown to greenish brown rings with straw-colored centers, frequently developing on the leaf sheath at soil level

ORANGE

Leaf Rust (Brown Rust)

Circular or slightly elliptical pustules containing masses of orange to orange-brown urediospores; most noticeable on the upper surfaces of leaves and leaf sheaths and occasionally on the neck and awns

Leaf Rust (Brown Rust); Stem Rust (Black Rust); Stripe Rust (Yellow Rust)

Raised pustules with yellow, orange, brown or black spores on the stems

SILVER

Thrips (various species)

Thrips generally feed on the flag leaf but may also be found on the leaves, stems, and heads; infested tissue takes on a silver discoloration; thrips are brown or black insects 1 mm long with a tapered, segmented abdomen

TAN

Common Root Rot; Foot Rot; Crown Rot

Uniform tan-brown discoloration on stems

WHITE

Frost Damage

Chlorosis of affected tissues is the common symptom; severe frost will result in death of the tissues and take on a bleached appearance; light frost will result in a band or stripe on the leaves or spikes; plants may become sterile

Powdery Mildew

Superficial white, pinkish, or gray fungal tissue on the stem

Take-All

This fungus causes rotting of the roots and lower stems causing them to turn shiny black; coarse, black runner hyphae are conspicuous on roots; severe infestation is indicated by stunted plants with whitened stems and spikes

YELLOW

Eyespot (Strawbreaker)

Eye-shaped, elliptical lesions develop on the internodes of the lower stem and are bordered by dark brown to greenish brown rings with straw-colored centers, frequently developing on the leaf sheath at soil level

Leaf Rust (Brown Rust); Stem Rust (Black Rust); Stripe Rust (Yellow Rust)

Raised pustules with yellow, orange, brown or black spores on the stems

Sawfly

Damage includes premature yellowing of the head and shriveling of the grain; the larvae girdle the stem and later cause lodging

YELLOW/BROWN

Alternaria Leaf Blight

Small, chlorotic, oval- or elliptical- lesions appear on all plant parts, becoming large irregular blotches; chlorotic borders may turn light to dark brown in color infection usually start on the lower leaves

No Distinct Discoloration

Armyworms, Cutworms, Stalkborers, Grasshoppers, and Crickets (various species)

Primary symptom is defoliation; larvae feed on leaves, chewing from the edges to the midrib, or on the heads of cereal plants but may move into the plant and sever the neck

Hybrid Necrosis

Dwarf clumping

Hybrid Necrosis (Dwarf Clumping)

Affected plants show differing degrees of necrosis and spotting often associated with stunting or dwarf clumping

Slugs and Snails (various species)

Slugs and snails can feed on the endosperm of germinating seed, bite seedlings off at ground level, and graze older plants, chewing longitudinal stripes on the leaves causing them to become frayed

Spot blotch; Eyespot; Rhizoctonia Root Rot; Hessian Fly; Sawfly; Frost Damage

Lodging, broken stems

Leaf

BLACK

Cereal Leaf Beetle

Adult beetles are 4-5 mm long with a black head, light brown thorax, shiny blue-green wing cover with parallel lines of small dots; larvae are a dull to bright yellow color becoming a slimy, globular, black mass; longitudinal stripes develop on the leaves

Flag Smut

Masses of black teliospores develop in narrow strips beneath the epidermis of leaves, leaf sheaths and sometimes the culms; diseases plants are stunted, tiller profusely, and spikes may not emerge; leaves may roll and the epidermis may shred

Leaf Rust (Brown Rust); Stem Rust (Black Rust); Stripe Rust (Yellow Rust); Flag Smut

Raised pustules on leaves with yellow, orange or black spores

Septoria Diseases; Septoria tritici, Septoria nodorum, Septoria avanae f.sp. triticea

Oval to elongated spots or lesions can appear on all aboveground plant parts; centers of lesions are pale to straw-colored, necrotic, and contain numerous small black dots; heavy infestations can cause death; identification is difficult

BLUE

Phosphorus Deficiency

Deficiency ranges from stunted plants with fewer shoots to pale to yellowish red leaves, starting with the lower leaves and moving from the leaf tips inward; affected tissue may turn brown and die; green portions of the leaves may be bluish-green

Salt Stress

Crop growth is inconsistent within the field; plants are stunted and blue-green in color with tip burn and firing on leaf margins

BROWN

Copper Deficiency

Discoloration of young leaf tips, followed by breaking and curling of the leaves; plant may also produce bleached and sterile spikes or the spike may never emerge

Helminthosporium Leaf Blotch (Spot Blotch)

Dark brown, oval lesions develop on all plant parts; older lesions may turn light brown to tan in color and develop an irregular dark brown ring

Phosphorus Deficiency

Deficiency ranges from stunted plants with fewer shoots to pale to yellowish red leaves, starting with the lower leaves and moving from the leaf tips inward; affected tissue may turn brown and die; green portions of the leaves may be bluish-green

Potassium Deficiency

Severe deficiency will cause the shortening of internodes, and the tips of margins of the lower leaves will become dry and scorched

Seed Gall Nematode (Wheat Nematode or Ear Cockle)

Distorted leaves and stems appear prior to heading; dark brown galls are formed in the florets upon maturity, replacing the kernels; masses of motile larvae are present within the galls and become active after the galls have been moistened

Septoria Tritici Blotch

Dark fungal fruiting bodies within brownish gray lesions on leaves

Sharp Eyespot and Rhizoctonia Root Rot

Dark brown lesions with pale, straw-colored centers develop on basal leaf sheaths; mycelia often are present in the centers of lesions and are easily removed by rubbing; roots can become brown and reduced in number; disease can cause stunting

BROWN/BLACK

Basal Glume Rot and Bacterial Leaf Blight

Lesions start small, green, water-soaked lesions that turn dark brown to blackish; lesions start at the base of the glume and extend over the whole glume eventually turning brown; lesions may develop on kernels; white-gray ooze may be present when moist

BROWN/BLACK/PURPLE

Melanism and Brown Necrosis (False Black Chaff)

Brownish black to dark purple spots, streaks, or blotches appear on the leaf sheaths, stems, and/or glumes; dark brown pigmentation usually develops on the glumes and peduncles

DARK

Spot Blotch; Black Point; Black Molds

Superficial dark fungal tissue on leaves

GRAY

Fusarium Leaf Blotch

Young lesions usually develop where the leaf bends and are oval to elliptical, resembling a gray-green mottle; lesions develop quickly with light gray centers; leaves tend to split or shred at centers of the lesions

Manganese Deficiency

Grayish necrotic spots of streaks appear on the basal portion of the newest leaves and the necrotic spots may extend across the blade causing the upper portion of the leaf to kink or twist

Powdery Mildew; Scab (Head Blight)

Superficial white, pinkish or gray fungal tissue on leaves

Septoria Tritici Blotch

Dark fungal fruiting bodies within brownish gray lesions on leaves

GREEN

Genetic Flecking

Numerous diseases cause chlorotic flecking but self-inflicted or genetically controlled flecking is common in small grain cereals; flecks vary from small pinpoints to large blotches; leaves may be a pale green color

Nitrogen Deficiency

Nitrogen deficient wheat appears pale green and lower leaves become yellow, usually from the tip to the sheath, followed necrosis if the deficiency persists

Phosphorus Deficiency

Deficiency ranges from stunted plants with fewer shoots to pale to yellowish red leaves, starting with the lower leaves and moving from the leaf tips inward; affected tissue may turn brown and die; green portions of the leaves may be bluish-green

Salt Stress

Crop growth is inconsistent within the field; plants are stunted and blue-green in color with tip burn and firing on leaf margins

ORANGE

Leaf Rust (Brown Rust)

Circular or slightly elliptical pustules containing masses of orange to orange-brown urediospores; most noticeable on the upper surfaces of leaves and leaf sheaths and occasionally on the neck and awns

Leaf Rust (Brown Rust); Stem Rust (Black Rust); Stripe Rust (Yellow Rust); Flag Smut

Raised pustules on leaves with yellow, orange or black spores

Leaf Rust (Brown Rust); Stem Rust (Black Rust); Stripe Rust (Yellow Rust); Powdery Mildew; Spot Blotch; Barley Yellow Dwarf; Thrips; Mites; Genetic Flecking

Flecks on the leaves

Leaf Rust (Brown Rust); Stem Rust (Black Rust); Stripe Rust (Yellow Rust); Tan Spot (Yellow Leaf Spot or Blotch); Physiological Leaf Spot; Minor Element Deficiencies

Lesions or blotches resembling halos with contrasting colored borders

Stripe Rust (Yellow Rust)

Yellow to orange yellow pustules form in narrow stripes on the leaves, leaf sheaths, necks and glumes

PINK

Powdery Mildew; Scab (Head Blight)

Superficial white, pinkish or gray fungal tissue on leaves

PURPLE

Aphids (various species)

Aphids are transparent, soft-bodied insects causing yellowing and premature death of leaves; infestations cause development of necrotic areas, purpling and rolling of the leaves; some species produce long white stripes on the leaves and prostrate growth

Barley Yellow Dwarf; Nitrogen, Phosphorus, Potassium Deficiency; Aluminum Toxicity

Reddening leaves and stunted growth

Phosphorus Deficiency

Deficiency ranges from stunted plants with fewer shoots to pale to yellowish red leaves, starting with the lower leaves and moving from the leaf tips inward; affected tissue may turn brown and die; green portions of the leaves may be bluish-green

Stem Rust (Black Rust)

Dark reddish brown pustules on the leaves, stems and spikes; pustules may be separate or coalesce together with heavy infestations; before the spore masses break through the epidermis the infection sites may feel rough and take on a ragged appearance

SILVER

Mites (various species)

Most mites have 4 legs and are in large numbers causing a silvery flecking on leaves; some species may produce webs and/or may cause infested plants to be severely stunted, to head poorly, and to turn white

Thrips (various species)

Thrips generally feed on the flag leaf but may also be found on the leaves, stems, and heads; infested tissue takes on a silver discoloration; thrips are brown or black insects 1 mm long with a tapered, segmented abdomen

TAN

Tan Spot (Yellow Leaf Spot or Blotch); Physiological Leaf Spot; Melanism and Brown Necrosis; Genetic Flecking; Herbicide Damage

Spots on the leaves

WHITE

Aphids (various species)

Aphids are transparent, soft-bodied insects causing yellowing and premature death of leaves; infestations cause development of necrotic areas, purpling and rolling of the leaves; some species produce long white stripes on the leaves and prostrate growth

Frost Damage

Chlorosis of affected tissues is the common symptom; severe frost will result in death of the tissues and take on a bleached appearance; light frost will result in a band or stripe on the leaves or spikes; plants may become sterile

Herbicide Damage

Broadleaf herbicides applied too early cause leaf curling and deformed spikes and possible sterility; bleached leaves followed by necrosis are the result of residues of triazines in the soil

Powdery Mildew; Scab (Head Blight)

Superficial white, pinkish or gray fungal tissue on leaves

YELLOW

Aluminum Toxicity

High concentration of aluminum give roots a stubby appearance and brown color; leaves are small and internodes are shortened and thickened; leaf tips may die and old leaves may become yellow and brittle

Aphids (various species)

Aphids are transparent, soft-bodied insects causing yellowing and premature death of leaves; infestations cause development of necrotic areas, purpling and rolling of the leaves; some species produce long white stripes on the leaves and prostrate growth

Bacterial Black Chaff

Narrow chlorotic lesions or stripes on the glumes that have a water-soaked appearance; droplets of sticky yellow exudate may appear with rain or dew and form crusty droplets when dry; entire leaves and spikes may die with infection; spikes may be sterile

Bacterial Spike Blight (Yellow Ear Rot)

A yellow exudate develops on the spikes becoming white, when dry; spikes and necks may emerge as a distorted, sticky mass; early leaves may also be wrinkled or twisted

Bacterial Stripe

Narrow chlorotic lesions or stripes on the leaves that have a water-soaked appearance; droplets of sticky yellow exudate may appear with rain or dew and form crusty droplets when dry; entire leaves and spikes may die with infection; spikes may be sterile

Barley Yellow Dwarf

Affected plants show a yellowing or reddening of leaves, stunting, and upright posture of thickened stiff leaves, reduced root growth, delayed (or no) heading, and a reduction of yield; head affected tend to remain erect and become black and discolored

Downy Mildew

Plants tiller profusely with short, erect, crooked yellowish-green culms; leaves are thick, erect with whorls; tillers die prematurely or never head, if formed, the heads may be branched and some of the floral tissues grow into leaflike structures

Flag Smut; Downy Mildew; Barley Yellow Dwarf; Mites; Seed Gall Nematode; Minor Element Deficiency; Herbicide Damage

Deformed, curled, rolled, twisted or thickened leaves and/or leaf sheaths

Genetic Flecking

Numerous diseases cause chlorotic flecking but self-inflicted or genetically controlled flecking is common in small grain cereals; flecks vary from small pinpoints to large blotches; leaves may be a pale green color

Leaf Rust (Brown Rust); Stem Rust (Black Rust); Stripe Rust (Yellow Rust); Flag Smut

Raised pustules on leaves with yellow, orange or black spores

Nitrogen Deficiency

Nitrogen deficient wheat appears pale green and lower leaves become yellow, usually from the tip to the sheath, followed necrosis if the deficiency persists

Nutrient Deficiencies

Yellowing, chlorosis, necrosis on the leaves and stunted growth

Phosphorus Deficiency

Deficiency ranges from stunted plants with fewer shoots to pale to yellowish red leaves, starting with the lower leaves and moving from the leaf tips inward; affected tissue may turn brown and die; green portions of the leaves may be bluish-green

Powdery Mildew

Patches of white to pale gray, fuzzy or powdery mycelia develop on the upper surfaces of leaves, leaf sheaths or spikes; older fungal tissue may be yellowish gray and easily rubbed off; the underlying tissue may be chlorotic or necrotic causing leaf death

Stripe Rust (Yellow Rust)

Yellow to orange yellow pustules form in narrow stripes on the leaves, leaf sheaths, necks and glumes

YELLOW/BROWN

Alternaria Leaf Blight

Small, chlorotic, oval- or elliptical- lesions appear on all plant parts, becoming large irregular blotches; chlorotic borders may turn light to dark brown in color infection usually start on the lower leaves

YELLOW/GRAY

Black Chaff; Bacterial Stripe; Basal Glume Rot; Bacterial Leaf Blight

Yellow to gray-white exudate on the leaves

No Distinct Discoloration

Armyworms, Cutworms, Stalkborers, Grasshoppers, and Crickets (various species)

Primary symptom is defoliation; larvae feed on leaves, chewing from the edges to the midrib, or on the heads of cereal plants but may move into the plant and sever the neck

Armyworms; Cutworms; Stalk Borers; Slugs; Snails; Grasshoppers; Crickets

Chewed, tattered, eaten or missing leaves

Cereal Leaf Beetle; Slugs; Snails; Grasshoppers; Crickets

Chewed longitudinal stripe

Heat Stress

High temperature cause plants to mature early and the number of spikelets and florets are reduced; grains may not fill adequately or completely if subjected to extreme temperatures; very high temperatures may result in the death of the plant

Hybrid Necrosis

Dwarf clumping

Hybrid Necrosis (Dwarf Clumping)

Affected plants show differing degrees of necrosis and spotting often associated with stunting or dwarf clumping

Moisture Stress

Young plants will be stunted and have reduced tillering and root development; leaves may curl and roll during the hottest part of the day; development of spikelets and florets may be reduced; grain may shrivel; death may occur in plants needing water

Root Knot Nematode

Small knots or galls grow near the tips of the roots; infested plants are stunted and chlorotic; roots may excessively branch

Slugs and Snails (various species)

Slugs and snails can feed on the endosperm of germinating seed, bite seedlings off at ground level, and graze older plants, chewing longitudinal stripes on the leaves causing them to become frayed

Flower

YELLOW

Downy Mildew

Plants tiller profusely with short, erect, crooked yellowish-green culms; leaves are thick, erect with whorls; tillers die prematurely or never head, if formed, the heads may be branched and some of the floral tissues grow into leaflike structures

YELLOW/BROWN

Alternaria Leaf Blight

Small, chlorotic, oval- or elliptical- lesions appear on all plant parts, becoming large irregular blotches; chlorotic borders may turn light to dark brown in color infection usually start on the lower leaves

Fruit

BLACK

Alternaria Leaf Blight; Scab; Black Point; Black Molds; Seed Gall Nematode

Seed discolored

Barley Yellow Dwarf

Affected plants show a yellowing or reddening of leaves, stunting, and upright posture of thickened stiff leaves, reduced root growth, delayed (or no) heading, and a reduction of yield; head affected tend to remain erect and become black and discolored

Black Molds (Sooty Molds)

Mature or dead spikes become blackened from the accumulation of mycelia and sporulating fungal tissue

Black Point

Pericarps of kernels turn dark brown to black on the germ end of the kernel

Common and Dwarf Bunt (Stinking Smut)

Bunt balls, fungal structures resembling kernels, develop and are completely filled with black teliospores and have a fishy odor when crushed; infected spikes may be bluish in color and the glumes may spread apart; plant may be slightly dwarfed

Ergot

Infected flowering florets produce a yellow, sticky sweet exudate on the glumes; these infected areas become brown to purplish black structures as the spike matures

Leaf Rust (Brown Rust); Stem Rust (Black Rust); Stripe Rust (Yellow Rust)

Raised pustules with yellow, orange, brown, or black spores on the head

Loose Smut

Entire spike black, transformed into a powdery mass

Loose Smut

Seeds have a black color; transformed into a powdery mass

Loose Smut

Black teliospores develop on the entire inflorescence and can be easily blown away leaving only the bare rachis and remnants of other floral structures

Septoria Tritici Blotch; Spot Blotch; Tan Spot (Yellow Leaf Spot or Blotch); Black Chaff; Bacterial Stripe; Melanism and Brown Necrosis

Brown, black, or purple blotches or streaks on the glumes

BROWN

Bacterial Stripe

Narrow chlorotic lesions or stripes on the leaves that have a water-soaked appearance; droplets of sticky yellow exudate may appear with rain or dew and form crusty droplets when dry; entire leaves and spikes may die with infection; spikes may be sterile

Ergot

Seed is hard; brown to black in color

Leaf Rust (Brown Rust); Stem Rust (Black Rust); Stripe Rust (Yellow Rust)

Raised pustules with yellow, orange, brown, or black spores on the head

Septoria Tritici Blotch; Spot Blotch; Tan Spot (Yellow Leaf Spot or Blotch); Black Chaff; Bacterial Stripe; Melanism and Brown Necrosis

Brown, black, or purple blotches or streaks on the glumes

BROWN/BLACK/PURPLE

Melanism and Brown Necrosis (False Black Chaff)

Brownish black to dark purple spots, streaks, or blotches appear on the leaf sheaths, stems, and/or glumes; dark brown pigmentation usually develops on the glumes and peduncles

DARK

Black Molds

Superficial dark fungal tissue on the head

GRAY/BLACK

Common and Dwarf Bunt (Stinking Smut); Kernel Bunt (Partial Bunt) (Partial Bunt)

Seed easily crushable and has a strong odor; color is gray to black

LIGHT

Copper Deficiency

Discoloration of young leaf tips, followed by breaking and curling of the leaves; plant may also produce bleached and sterile spikes or the spike may never emerge

ORANGE

Leaf Rust (Brown Rust); Stem Rust (Black Rust); Stripe Rust (Yellow Rust)

Raised pustules with yellow, orange, brown, or black spores on the head

Stripe Rust (Yellow Rust)

Yellow to orange yellow pustules form in narrow stripes on the leaves, leaf sheaths, necks and glumes

PINK

Powdery Mildew; Scab

Superficial white, pinkish or gray fungal tissue on the head

Scab (Head Blight)

Infected florets become slightly darkened and oily and conidiospores develop giving the spike a bright pinkish color; infected kernels and surface of the florets may be covered with white mycelia

PURPLE

Ergot

Infected flowering florets produce a yellow, sticky sweet exudate on the glumes; these infected areas become brown to purplish black structures as the spike matures

Septoria Tritici Blotch; Spot Blotch; Tan Spot (Yellow Leaf Spot or Blotch); Black Chaff; Bacterial Stripe; Melanism and Brown Necrosis

Brown, black, or purple blotches or streaks on the glumes

SILVER

Thrips (various species)

Thrips generally feed on the flag leaf but may also be found on the leaves, stems, and heads; infested tissue takes on a silver discoloration; thrips are brown or black insects 1 mm long with a tapered, segmented abdomen

YELLOW

Bacterial Spike Blight (Yellow Ear Rot)

A yellow exudate develops on the spikes becoming white, when dry; spikes and necks may emerge as a distorted, sticky mass; early leaves may also be wrinkled or twisted

WHITE

Bacterial Spike Blight (Yellow Ear Rot)

A yellow exudate develops on the spikes becoming white, when dry; spikes and necks may emerge as a distorted, sticky mass; early leaves may also be wrinkled or twisted

Root Rot, Foot Rot, and Crown Rot

Darkening or browning of the root, crown and basal culm tissues; individual plants or groups of plants may lodge; white spikes often are visible just prior to normal physiological maturity

Frost Damage

Chlorosis of affected tissues is the common symptom; severe frost will result in death of the tissues and take on a bleached appearance; light frost will result in a band or stripe on the leaves or spikes; plants may become sterile

Leaf Rust (Brown Rust); Black Molds; Barley Yellow Dwarf; Stink Bugs; Wheat Stem Maggot; Sawfly; Minor Element Deficiencies; Frost Damage

Entire head white, forced ripening, seeds shriveled or absent

Mites (various species)

Most mites have 4 legs and are in large numbers causing a silvery flecking on leaves; some species may produce webs and/or may cause infested plants to be severely stunted, to head poorly, and to turn white

Powdery Mildew; Scab

Superficial white, pinkish or gray fungal tissue on the head

Scab (Head Blight)

Infected florets become slightly darkened and oily and conidiospores develop giving the spike a bright pinkish color; infected kernels and surface of the florets may be covered with white mycelia

Take-All

This fungus causes rotting of the roots and lower stems causing them to turn shiny black; coarse, black runner hyphae are conspicuous on roots; severe infestation is indicated by stunted plants with whitened stems and spikes

Wheat Stem Maggot

Young tillers attacked usually die; infested plants show the white head; the adult flies are about 6 mm in length, pale green to yellow with dark stripes

WHITE/GRAY

Basal Glume Rot and Bacterial Leaf Blight

Lesions start small, green, water-soaked lesions that turn dark brown to blackish; lesions start at the base of the glume and extend over the whole glume eventually turning brown; lesions may develop on kernels; white-gray ooze may be present when moist

YELLOW

Bacterial Black Chaff

Narrow chlorotic lesions or stripes on the glumes that have a water-soaked appearance; droplets of sticky yellow exudate may appear with rain or dew and form crusty droplets when dry; entire leaves and spikes may die with infection; spikes may be sterile

Black Chaff; Bacterial Stripe; Bacterial Spike Blight

Yellow exudate on the head

Downy Mildew

Plants tiller profusely with short, erect, crooked yellowish-green culms; leaves are thick, erect with whorls; tillers die prematurely or never head, if formed, the heads may be branched and some of the floral tissues grow into leaflike structures

Downy Mildew; Bacterial Spike Blight; Barley Yellow Dwarf; Seed Gall Nematode; Minor Element Deficiency; Herbicide Damage; Frost Damage

Head is twisted or otherwise distorted, may not emerge from leaf sheath

Leaf Rust (Brown Rust); Stem Rust (Black Rust); Stripe Rust (Yellow Rust)

Raised pustules with yellow, orange, brown, or black spores on the head

Stripe Rust (Yellow Rust)

Yellow to orange yellow pustules form in narrow stripes on the leaves, leaf sheaths, necks and glumes

YELLOW/BROWN

Alternaria Leaf Blight

Small, chlorotic, oval- or elliptical- lesions appear on all plant parts, becoming large irregular blotches; chlorotic borders may turn light to dark brown in color infection usually start on the lower leaves

No Distinct Discoloration

Karnal Bunt (Partial Bunt)

Diseased kernels develop a black mass of teliospores that replaces much of the endosperm; a fishy odor is present when the kernels are crushed

Moisture Stress

Young plants will be stunted and have reduced tillering and root development; leaves may curl and roll during the hottest part of the day; development of spikelets and florets may be reduced; grain may shrivel; death may occur in plants needing water

Heat Stress

High temperature cause plants to mature early and the number of spikelets and florets are reduced; grains may not fill adequately or completely if subjected to extreme temperatures; very high temperatures may result in the death of the plant