Small Grains:Key
KEY TO WHEAT PESTS AND NUTRITIONAL DISORDERS
Contents
- 1 Seed
- 2 Seedling
- 3 Root
- 4 Crown
- 5 Stem
- 5.1 BLACK
- 5.2 BROWN
- 5.2.1 Eyespot (Strawbreaker)
- 5.2.2 Eyespot; Sharp Eyespot with Rhizoctonia Root Rot
- 5.2.3 Leaf Rust (Brown Rust); Stem Rust (Black Rust); Stripe Rust (Yellow Rust)
- 5.2.4 Seed Gall Nematode (Wheat Nematode or Ear Cockle)
- 5.2.5 Septoria Tritici Blotch; Black Chaff; Bacterial Stripe; Physiological Leaf Spot
- 5.2.6 Stem Rust (Black Rust)
- 5.2.7 Wireworms (various species)
- 5.2.8 Tan Spot (Yellow Leaf Spot or Blotch)
- 5.3 BROWN/BLACK/PURPLE
- 5.4 GRAY
- 5.5 GRAY
- 5.6 GREEN
- 5.7 ORANGE
- 5.8 SILVER
- 5.9 TAN
- 5.10 WHITE
- 5.11 YELLOW
- 5.12 YELLOW/BROWN
- 5.13 No Distinct Discoloration
- 6 Leaf
- 6.1 BLACK
- 6.2 BLUE
- 6.3 BROWN
- 6.4 BROWN/BLACK
- 6.5 BROWN/BLACK/PURPLE
- 6.6 DARK
- 6.7 GRAY
- 6.8 GREEN
- 6.9 ORANGE
- 6.9.1 Leaf Rust (Brown Rust)
- 6.9.2 Leaf Rust (Brown Rust); Stem Rust (Black Rust); Stripe Rust (Yellow Rust); Flag Smut
- 6.9.3 Leaf Rust (Brown Rust); Stem Rust (Black Rust); Stripe Rust (Yellow Rust); Powdery Mildew; Spot Blotch; Barley Yellow Dwarf; Thrips; Mites; Genetic Flecking
- 6.9.4 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
- 6.9.5 Stripe Rust (Yellow Rust)
- 6.10 PINK
- 6.11 PURPLE
- 6.12 SILVER
- 6.13 TAN
- 6.14 WHITE
- 6.15 YELLOW
- 6.15.1 Aluminum Toxicity
- 6.15.2 Aphids (various species)
- 6.15.3 Bacterial Black Chaff
- 6.15.4 Bacterial Spike Blight (Yellow Ear Rot)
- 6.15.5 Bacterial Stripe
- 6.15.6 Barley Yellow Dwarf
- 6.15.7 Downy Mildew
- 6.15.8 Flag Smut; Downy Mildew; Barley Yellow Dwarf; Mites; Seed Gall Nematode; Minor Element Deficiency; Herbicide Damage
- 6.15.9 Genetic Flecking
- 6.15.10 Leaf Rust (Brown Rust); Stem Rust (Black Rust); Stripe Rust (Yellow Rust); Flag Smut
- 6.15.11 Nitrogen Deficiency
- 6.15.12 Nutrient Deficiencies
- 6.15.13 Phosphorus Deficiency
- 6.15.14 Powdery Mildew
- 6.15.15 Stripe Rust (Yellow Rust)
- 6.16 YELLOW/BROWN
- 6.17 YELLOW/GRAY
- 6.18 No Distinct Discoloration
- 6.18.1 Armyworms, Cutworms, Stalkborers, Grasshoppers, and Crickets (various species)
- 6.18.2 Armyworms; Cutworms; Stalk Borers; Slugs; Snails; Grasshoppers; Crickets
- 6.18.3 Cereal Leaf Beetle; Slugs; Snails; Grasshoppers; Crickets
- 6.18.4 Heat Stress
- 6.18.5 Hybrid Necrosis
- 6.18.6 Hybrid Necrosis (Dwarf Clumping)
- 6.18.7 Moisture Stress
- 6.18.8 Root Knot Nematode
- 6.18.9 Slugs and Snails (various species)
- 7 Flower
- 8 Fruit
- 8.1 BLACK
- 8.1.1 Alternaria Leaf Blight; Scab; Black Point; Black Molds; Seed Gall Nematode
- 8.1.2 Barley Yellow Dwarf
- 8.1.3 Black Molds (Sooty Molds)
- 8.1.4 Black Point
- 8.1.5 Common and Dwarf Bunt (Stinking Smut)
- 8.1.6 Ergot
- 8.1.7 Leaf Rust (Brown Rust); Stem Rust (Black Rust); Stripe Rust (Yellow Rust)
- 8.1.8 Loose Smut
- 8.1.9 Loose Smut
- 8.1.10 Loose Smut
- 8.1.11 Septoria Tritici Blotch; Spot Blotch; Tan Spot (Yellow Leaf Spot or Blotch); Black Chaff; Bacterial Stripe; Melanism and Brown Necrosis
- 8.2 BROWN
- 8.3 BROWN/BLACK/PURPLE
- 8.4 DARK
- 8.5 GRAY/BLACK
- 8.6 LIGHT
- 8.7 ORANGE
- 8.8 PINK
- 8.9 PURPLE
- 8.10 SILVER
- 8.11 YELLOW
- 8.12 WHITE
- 8.12.1 Bacterial Spike Blight (Yellow Ear Rot)
- 8.12.2 Root Rot, Foot Rot, and Crown Rot
- 8.12.3 Frost Damage
- 8.12.4 Leaf Rust (Brown Rust); Black Molds; Barley Yellow Dwarf; Stink Bugs; Wheat Stem Maggot; Sawfly; Minor Element Deficiencies; Frost Damage
- 8.12.5 Mites (various species)
- 8.12.6 Powdery Mildew; Scab
- 8.12.7 Scab (Head Blight)
- 8.12.8 Take-All
- 8.12.9 Wheat Stem Maggot
- 8.13 WHITE/GRAY
- 8.14 YELLOW
- 8.14.1 Bacterial Black Chaff
- 8.14.2 Black Chaff; Bacterial Stripe; Bacterial Spike Blight
- 8.14.3 Downy Mildew
- 8.14.4 Downy Mildew; Bacterial Spike Blight; Barley Yellow Dwarf; Seed Gall Nematode; Minor Element Deficiency; Herbicide Damage; Frost Damage
- 8.14.5 Leaf Rust (Brown Rust); Stem Rust (Black Rust); Stripe Rust (Yellow Rust)
- 8.14.6 Stripe Rust (Yellow Rust)
- 8.15 YELLOW/BROWN
- 8.16 No Distinct Discoloration
- 8.1 BLACK
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