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Revision as of 02:08, 7 February 2016
KEY TO BARLEY PESTS AND NUTRITIONAL DISORDERS
Contents
- 1 Seed=
- 2 Seedling=
- 3 Root
- 4 Crown=
- 5 Stem
- 6 Leaf
- 6.1 BLACK
- 6.2 BLUE/GRAY
- 6.3 BROWN
- 6.3.1 Bacterial leaf streak
- 6.3.2 Bacterial stripe blight
- 6.3.3 Barley stripe mosaic
- 6.3.4 Boron toxicity
- 6.3.5 Bromoxynil
- 6.3.6 Cephalosporium stripe
- 6.3.7 Chlorine
- 6.3.8 Common root rot
- 6.3.9 Eyespot
- 6.3.10 Glume blotch
- 6.3.11 Halo spot
- 6.3.12 Leaf rust
- 6.3.13 Manganese deficiency
- 6.3.14 Manganese deficiency
- 6.3.15 Net blotch
- 6.3.16 Phosphorus deficiency
- 6.3.17 Physiologic leaf spots
- 6.3.18 Scald
- 6.3.19 Semiloose smut
- 6.3.20 Septoria leaf blotch (S. avenae f. sp. triticea)
- 6.3.21 Spot blotch
- 6.3.22 Spot blotch
- 6.3.23 True loose smut
- 6.3.24 Yellow leaf spot
- 6.4 DARK
- 6.5 GREEN
- 6.6 LIGHT
- 6.7 OLIVE
- 6.8 PALE GREEN
- 6.9 PINK/PURPLE
- 6.10 PURPLE
- 6.11 RED
- 6.12 TAN
- 6.13 WHITE
- 6.14 YELLOW
- 6.14.1 Aster yellows
- 6.14.2 Barley mosaic
- 6.14.3 Barley mosaic
- 6.14.4 Barley stripe
- 6.14.5 Barley yellow dwarf
- 6.14.6 Barley yellow mosaic
- 6.14.7 Cephalosporium stripe
- 6.14.8 Cereal root-knot nematode
- 6.14.9 Chlorine
- 6.14.10 Copper deficiency
- 6.14.11 Diclofop methyl
- 6.14.12 Downy mildew
- 6.14.13 Glume blotch
- 6.14.14 Iron deficiency
- 6.14.15 Leptosphaeria leaf spot
- 6.14.16 Manganese deficiency
- 6.14.17 Metribuzin
- 6.14.18 Nitrogen deficiency
- 6.14.19 Ozone
- 6.14.20 Root-gall nematode
- 6.14.21 Stripe rust
- 6.14.22 Stunt nematode
- 6.14.23 Sulfur deficiency
- 6.14.24 Temperature stress
- 6.14.25 Yellow leaf spot
- 6.15 No Distinct Discoloration
- 7 Flower
- 8 Fruit
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
Sharp eyespot
Small, sharply delineated lesions on seedlings; center of lesion may rot, leaving a small hole surrounded by dark brown tissue
DARK
Sharp eyespot
Small, sharply delineated lesions on seedlings; center of lesion may rot, leaving a small hole surrounded by dark brown tissue
WHITE
Propanil
Yellowing, whitening of seedling leaves
Temperature stress
Yellow-white transverse bands on seedling leaves
YELLOW
Barley stripe
Longitudinal yellow stripes on seedling leaves, extending to all leaves; leaves eventually become necrotic and tend to shred and fray at the ends; infected plants are stunted, and spikes fail to emerge or become twisted, blighted, or compressed
Propanil
Yellowing, whitening of seedling leaves
Temperature stress
Yellow-white transverse bands on seedling leaves
No Distinct Discoloration
Barban
Distorted growth of second and subsequent seedling leaves
Browning root rot
Roots soft and tan to light brown; brown lesions on larger roots; oospores develop within root tissue; infected plants are stunted, with a few short, stubby roots
Calcium deficiency
Dead leaf tips on seedlings and stunted growth
Cereal root-knot nematode
Small curved galls on roots, especially near root tips; plants are stunted and yellowed
Seedling blight
Seedlings stunted or killed; roots and coleoptile brown
Snow molds
Mycelial growth on plants after snow melts, usually accompanied by small, dark sclerotia or pinkish red conidial masses; dead leaves quickly dry up
Root
BLACK
Take-all
Plants are stunted, often with white heads; roots break off when plants are pulled from the ground; roots are brittle and black, with black runner hyphae on root surface; base of culm is often covered with black mass of mycelium
BROWN
Browning root rot
Roots soft and tan to light brown; brown lesions on larger roots; oospores develop within root tissue; infected plants are stunted, with a few short, stubby roots
Cereal cyst nematode
Stunted plants with knotted, forked, and stunted root system; white cysts, later turning brown, on roots
Seedling blight
Seedlings stunted or killed; roots and coleoptile brown
TAN
Browning root rot
Roots soft and tan to light brown; brown lesions on larger roots; oospores develop within root tissue; infected plants are stunted, with a few short, stubby roots
WHITE
Cereal cyst nematode
Stunted plants with knotted, forked, and stunted root system; white cysts, later turning brown, on roots
YELLOW
Stunt nematode
Plants are stunted and yellowed, with short, stubby roots
No Distinct Discoloration
Cereal root-knot nematode
Small curved galls on roots, especially near root tips; plants are stunted and yellowed
Dicamba
Tillers grow flat on the ground, then bend up as plant matures; heads and awns are severely kinked
Root-gall nematode
Tips of outer leaves are chlorotic; roots are highly branched, with numerous galls
Root-lesion nematode
Oblong necrotic lesions on roots; plants are stunted
TCA, dalapon
Increased tillering
Crown=
BLACK
Take-all
Plants are stunted, often with white heads; roots break off when plants are pulled from the ground; roots are brittle and black, with black runner hyphae on root surface; base of culm is often covered with black mass of mycelium
BLUE/GRAY
Eyespot
Elliptical, eye-shaped, tan to brown lesions on leaf sheaths within 15-20 cm of the soil line; lesions are oriented longitudinally with the stem; weft of gray mycelium often within the lumen of the culm
BROWN
Common root rot
Small, oval to linear, brown lesions on subcrown internode and on lower leaf sheaths in the crown area; if fusaria are involved, a pink or purplish red cast may appear on the lower leaf sheath, particularly inside the leaf sheath
Net blotch
Lesions form a necrotic, netlike pattern on leaves; spot form of new blotch (dark-brown, elliptical lesions surrounded by a chlorotic zone) also occurs in some areas
DARK
Anthracnose
Lesions above the below ground on the lower portions of the culm, at first water-soaked then bleached and necrotic; dark acervuli with dark microscopic spines in lesions; severe infection causes lodging and head blight
PURPLE
Phosphorus deficiency
Bluish green leaves, often with brown of dead tips; purple pigment in leaves and culms
No Distinct Discoloration
Browning root rot
Roots soft and tan to light brown; brown lesions on larger roots; oospores develop within root tissue; infected plants are stunted, with a few short, stubby roots
Dicamba
Tillers grow flat on the ground, then bend up as plant matures; heads and awns are severely kinked
Potassium deficiency
Dwarfed shoots with short internodes; excessive tillering with few heads
Snow molds
Mycelial growth on plants after snow melts, usually accompanied by small, dark sclerotia or pinkish red conidial masses; dead leaves quickly dry up
Stem
BROWN
Eyespot
Elliptical, eye-shaped, tan to brown lesions on leaf sheaths within 15-20 cm of the soil line; lesions are oriented longitudinally with the stem; weft of gray mycelium often within the lumen of the culm
Halo spot
Elliptical, rectangular lesions on leaves and occasionally on culms; new lesions have purple-brown margins (halos) that fade with age; usually many pycnidia within lesions
DARK
Anthracnose
Lesions above the ground on the lower portions of the culm, at first water-soaked then bleached and necrotic; dark acervuli with dark microscopic spines in lesions; severe infection causes lodging and head blight
PURPLE
Halo spot
Elliptical, rectangular lesions on leaves and occasionally on culms; new lesions have purple-brown margins (halos) that fade with age; usually many pycnidia within lesions
RED
Stem rust
Brick red pustules with ragged edges on stems and leaf sheaths, sometimes on leaves, glumes and awns
TAN
Eyespot
Elliptical, eye-shaped, tan to brown lesions on leaf sheaths within 15-20 cm of the soil line; lesions are oriented longitudinally with the stem; weft of gray mycelium often within the lumen of the culm
WHITE
Bacterial leaf blight
Small, water-soaked lesions coalesce, turning gray-green, then tan or white; leaf eventually become necrotic
YELLOW
Stripe rust
Yellow pustules in long linear stripes primarily on leaves but sometimes on stems, glumes, and awns
Stunt nematode
Plants are stunted and yellowed, with short, stubby roots
No Distinct Discoloration
Barley yellow mosaic
Leaves show yellow spots and short streaks that later become yellow, beginning at the leaf tip; plants are stunted; older leaves may show necrotic spots, and leaves may die prematurely
Calcium deficiency
Dead leaf tips on seedlings and stunted growth
Cephalosporium stripe
Yellow leaf stripes with dark brown vascular bundles within the yellow stripe; plant is often stunted with white heads
Cereal cyst nematode
Stunted plants with knotted, forked, and stunted root system; white cysts, later turning brown, on roots
Cereal root-knot nematode
Small curved galls on roots, especially near root tips; plants are stunted and yellowed
Picloram
Twisted heads; prostrate, reduced growth
Root-lesion nematode
Oblong necrotic lesions on roots; plants are stunted
Snow molds
Mycelial growth on plants after snow melts, usually accompanied by small, dark sclerotia or pinkish red conidial masses; dead leaves quickly dry up
Zinc deficiency
Young plants with purple color, while older leaves die
Leaf
BLACK
Covered smut
Persistent membrane surrounds powdery black spores; in many cases, smutted heads become trapped in the flag leaf sheath
Septoria leaf blotch (Septoria passerinii)
Long linear lesions parallel to veins on leaves with definite margins; distinct, prominent, dark to black pycnidia in linear rows within the lesions
BLUE/GRAY
Bacterial leaf blight
Small, water-soaked lesions coalesce, turning gray-green, then tan or white; leaf eventually become necrotic
Glume blotch
Brown to gray spots on leaf blades and sheaths, later becoming oval or lens-shaped, red-brown spots with chlorotic tissue along the leaf veins; pycnidia often found in the lesions; later, spots develop on glumes and awns
Phosphorus deficiency
Bluish green leaves, often with brown of dead tips; purple pigment in leaves and culms
Scald
Irregular oval to oblong lesions, initially pale gray to blue-green and water-soaked, becoming bleached with dark brown border
Septoria leaf blotch (S. avenae f. sp. triticea)
Gray-green lesions turn tan and are highly variable in size, with indefinite margins; pycnidia usually appear as tan to brown specks scattered within the lesion
BROWN
Bacterial leaf streak
Brown, water-soaked lesions or, glumes
Bacterial stripe blight
Small, water-soaked lesions coalesce into stripes or blotches extending the length of the leaf, eventually turning translucent rusty brown; exudate may form, producing white scales on leaf surface
Barley stripe mosaic
Brown, necrotic stripes in leaves, often in V-shaped fashion; mosaic pattern in young leaves
Boron toxicity
Small brown spots on leaves
Bromoxynil
General wilting and leaf tip browning
Cephalosporium stripe
Yellow leaf stripes with dark brown vascular bundles within the yellow stripe; plant is often stunted with white heads
Chlorine
Tip and marginal leaf chlorosis, becoming tan to red-brown and necrotic
Common root rot
Small, oval to linear, brown lesions on subcrown internode and on lower leaf sheaths in the crown area; if fusaria are involved, a pink or purplish red cast may appear on the lower leaf sheath, particularly inside the leaf sheath
Eyespot
Elliptical, eye-shaped, tan to brown lesions on leaf sheaths within 15-20 cm of the soil line; lesions are oriented longitudinally with the stem; weft of gray mycelium often within the lumen of the culm
Glume blotch
Brown to gray spots on leaf blades and sheaths, later becoming oval or lens-shaped, red-brown spots with chlorotic tissue along the leaf veins; pycnidia often found in the lesions; later, spots develop on glumes and awns
Halo spot
Elliptical, rectangular lesions on leaves and occasionally on culms; new lesions have purple-brown margins (halos) that fade with age; usually many pycnidia within lesions
Leaf rust
Small, round, brown pustules on leaves and leaf sheaths, rarely in the heads
Manganese deficiency
Chlorotic leaves with mottled brown spots and stripes
Manganese deficiency
Chlorotic leaves with mottled brown spots and stripes
Net blotch
Lesions form a necrotic, netlike pattern on leaves; spot form of new blotch (dark-brown, elliptical lesions surrounded by a chlorotic zone) also occurs in some areas
Phosphorus deficiency
Bluish green leaves, often with brown of dead tips; purple pigment in leaves and culms
Physiologic leaf spots
Irregular clusters of small necrotic spots surrounding a brown spot
Scald
Irregular oval to oblong lesions, initially pale gray to blue-green and water-soaked, becoming bleached with dark brown border
Semiloose smut
Delicate membrane surround powdery, chocolate-brown spores and eventually fragments, releasing the spores; the naked rachis of the head remains
Septoria leaf blotch (S. avenae f. sp. triticea)
Gray-green lesions turn tan and are highly variable in size, with indefinite margins; pycnidia usually appear as tan to brown specks scattered within the lesion
Spot blotch
Round to oblong lesions of a uniform brown color, with a definite margin; spots may coalesce to form large blotches; heads and kernels may also be attacked
Spot blotch
Dark brown, necrotic lesions on glumes and rachis
True loose smut
Delicate membrane surrounds powdery, olive-brown spores and eventually fragments, releasing the spores; the naked rachis of the head remains
Yellow leaf spot
Tan flecks first seen on both sides of lower leaves, later on upper leaves; eventually, these flecks become tan, diamond-shaped lesions with a yellow border and dark brown spot in the center
DARK
Net blotch
Lesions form a necrotic, netlike pattern on leaves; spot form of new blotch (dark-brown, elliptical lesions surrounded by a chlorotic zone) also occurs in some areas
Scald
Irregular oval to oblong lesions, initially pale gray to blue-green and water-soaked, becoming bleached with dark brown border
Septoria leaf blotch (Septoria passerinii)
Long linear lesions parallel to veins on leaves with definite margins; distinct, prominent, dark to black pycnidia in linear rows within the lesions
Snow molds
Mycelial growth on plants after snow melts, usually accompanied by small, dark sclerotia or pinkish red conidial masses; dead leaves quickly dry up
Spot blotch
Dark brown, necrotic lesions on glumes and rachis
Yellow leaf spot
Tan flecks first seen on both sides of lower leaves, later on upper leaves; eventually, these flecks become tan, diamond-shaped lesions with a yellow border and dark brown spot in the center
GREEN
Scald
Irregular oval to oblong lesions, initially pale gray to blue-green and water-soaked, becoming bleached with dark brown border
Septoria leaf blotch (S. avenae f. sp. triticea)
Gray-green lesions turn tan and are highly variable in size, with indefinite margins; pycnidia usually appear as tan to brown specks scattered within the lesion
LIGHT
Anthracnose
Lesions above the ground on the lower portions of the culm, at first water-soaked then bleached and necrotic; dark acervuli with dark microscopic spines in lesions; severe infection causes lodging and head blight
Magnesium deficiency
Pale green leaves with necrotic areas near leaf margins
Sulfur deficiency
Pale yellow leaves, particularly younger leaves
OLIVE
True loose smut
Delicate membrane surrounds powdery, olive-brown spores and eventually fragments, releasing the spores; the naked rachis of the head remains
PALE GREEN
Magnesium deficiency
Pale green leaves with necrotic areas near leaf margins
PINK/PURPLE
Common root rot
Small, oval to linear, brown lesions on subcrown internode and on lower leaf sheaths in the crown area; if fusaria are involved, a pink or purplish red cast may appear on the lower leaf sheath, particularly inside the leaf sheath
PURPLE
Halo spot
Elliptical, rectangular lesions on leaves and occasionally on culms; new lesions have purple-brown margins (halos) that fade with age; usually many pycnidia within lesions
Phosphorus deficiency
Bluish green leaves, often with brown of dead tips; purple pigment in leaves and culms
Zinc deficiency
Young plants with purple color, while older leaves die
RED
Chlorine
Tip and marginal leaf chlorosis, becoming tan to red-brown and necrotic
Common root rot
Small, oval to linear, brown lesions on subcrown internode and on lower leaf sheaths in the crown area; if fusaria are involved, a pink or purplish red cast may appear on the lower leaf sheath, particularly inside the leaf sheath
Glume blotch
Brown to gray spots on leaf blades and sheaths, later becoming oval or lens-shaped, red-brown spots with chlorotic tissue along the leaf veins; pycnidia often found in the lesions; later, spots develop on glumes and awns
Snow molds
Mycelial growth on plants after snow melts, usually accompanied by small, dark sclerotia or pinkish red conidial masses; dead leaves quickly dry up
Stem rust
Brick red pustules with ragged edges on stems and leaf sheaths, sometimes on leaves, glumes and awns
TAN
Bacterial leaf blight
Small, water-soaked lesions coalesce, turning gray-green, then tan or white; leaf eventually become necrotic
Chlorine
Tip and marginal leaf chlorosis, becoming tan to red-brown and necrotic
Eyespot
Elliptical, eye-shaped, tan to brown lesions on leaf sheaths within 15-20 cm of the soil line; lesions are oriented longitudinally with the stem; weft of gray mycelium often within the lumen of the culm
Leptosphaeria leaf spot
Irregular, diffuse, yellow-tan leaf spots
Septoria leaf blotch (S. avenae f. sp. triticea)
Gray-green lesions turn tan and are highly variable in size, with indefinite margins; pycnidia usually appear as tan to brown specks scattered within the lesion
Sulfur dioxide
Leaves turn tan-white and appear scalded, often with dead spots or blotches
Yellow leaf spot
Tan flecks first seen on both sides of lower leaves, later on upper leaves; eventually, these flecks become tan, diamond-shaped lesions with a yellow border and dark brown spot in the center
WHITE
Bacterial stripe blight
Small, water-soaked lesions coalesce into stripes or blotches extending the length of the leaf, eventually turning translucent rusty brown; exudate may form, producing white scales on leaf surface
Sulfur dioxide
Leaves turn tan-white and appear scalded, often with dead spots or blotches
Temperature stress
Yellow-white transverse bands on seedling leaves
YELLOW
Aster yellows
Chlorotic blotches coalesce to cause general yellowing; leaves tend to roll inward; plant is severely stunted, often without heading; phyllody often results (if heads or produced), with twisted awns
Barley mosaic
Leaves are chlorotic and later show mosaic; plants are stunted
Barley mosaic
Leaves are chlorotic and later show mosaic; plants are stunted
Barley stripe
Longitudinal yellow stripes on seedling leaves, extending to all leaves; leaves eventually become necrotic and tend to shred and fray at the ends; infected plants are stunted, and spikes fail to emerge or become twisted, blighted, or compressed
Barley yellow dwarf
Discoloration beginning unevenly along leaf margins, at leaf tips, or within the leaf blade in blotches; eventually, brilliant yellowing of older leaves
Barley yellow mosaic
Leaves show yellow spots and short streaks that later become yellow, beginning at the leaf tip; plants are stunted; older leaves may show necrotic spots, and leaves may die prematurely
Cephalosporium stripe
Yellow leaf stripes with dark brown vascular bundles within the yellow stripe; plant is often stunted with white heads
Cereal root-knot nematode
Small curved galls on roots, especially near root tips; plants are stunted and yellowed
Chlorine
Tip and marginal leaf chlorosis, becoming tan to red-brown and necrotic
Copper deficiency
Tips of leaves with marginal chlorosis
Diclofop methyl
Interveinal yellowing
Downy mildew
Yellowed, thickened leaves on stunted plants; heads are often twisted and malformed; oospores are formed with infected tissue
Glume blotch
Brown to gray spots on leaf blades and sheaths, later becoming oval or lens-shaped, red-brown spots with chlorotic tissue along the leaf veins; pycnidia often found in the lesions; later, spots develop on glumes and awns
Iron deficiency
Chlorosis, particularly of young plant parts
Leptosphaeria leaf spot
Irregular, diffuse, yellow-tan leaf spots
Manganese deficiency
Chlorotic leaves with mottled brown spots and stripes
Metribuzin
Leaf yellowing after low temperatures
Nitrogen deficiency
Yellow leaves, first appearing on older basal leaves
Ozone
Slight chlorosis, usually on oldest leaves first
Root-gall nematode
Tips of outer leaves are chlorotic; roots are highly branched, with numerous galls
Stripe rust
Yellow pustules in long linear stripes primarily on leaves but sometimes on stems, glumes, and awns
Stunt nematode
Plants are stunted and yellowed, with short, stubby roots
Sulfur deficiency
Pale yellow leaves, particularly younger leaves
Temperature stress
Yellow-white transverse bands on seedling leaves
Yellow leaf spot
Tan flecks first seen on both sides of lower leaves, later on upper leaves; eventually, these flecks become tan, diamond-shaped lesions with a yellow border and dark brown spot in the center
No Distinct Discoloration
Bacterial leaf blight
Small, water-soaked lesions coalesce, turning gray-green, then tan or white; leaf eventually become necrotic
Barban
Distorted growth of second and subsequent seedling leaves
Dicamba
Tillers grow flat on the ground, then bend up as plant matures; heads and awns are severely kinked
Downy mildew
Yellowed, thickened leaves on stunted plants; heads are often twisted and malformed; oospores are formed with infected tissue
Fluoride
Necrosis at leaf margins and tips, delineated by a distinct margin
Frost
Sterile florets in head; water-soaking at base of peduncle
Potassium deficiency
Dwarfed shoots with short internodes; excessive tillering with few heads
Powdery mildew
Superficial cottony mycelial growth on leaves and sometimes heads; dark fruiting bodies develop within mycelium with age; colonies develop a powdery appearance as conidia develop on the mycelium
Flower
DARK
Anthracnose
Lesions above the below ground on the lower portions of the culm, at first water-soaked then bleached and necrotic; dark acervuli with dark microscopic spines in lesions; severe infection causes lodging and head blight
GRAY/POWDERY
Covered smut
Persistent membrane surrounds powdery black spores; in many cases, smutted heads become trapped in the flag leaf sheath
PURPLE/BLACK
Ergot
Purple-black, hornlike growth in the heads, replacing the seed
No Distinct Discoloration
Dicamba
Tillers grow flat on the ground, then bend up as plant matures; heads and awns are severely kinked
Downy mildew
Yellowed, thickened leaves on stunted plants; heads are often twisted and malformed; oospores are formed with infected tissue
Semiloose smut
Delicate membrane surround powdery, chocolate-brown spores and eventually fragments, releasing the spores; the naked rachis of the head remains
Fruit
BLACK
Black point
Embryo end of kernels dark brown to black
Ergot
Purple-black, hornlike growth in the heads, replacing the seed
Scab
Water-soaked spots on glumes followed by pink to reddish fluffy mycelial growth along edge of glumes; spikelets are prematurely bleached; blue-black perithecia may develop on glumes and kernels near harvest
BLUE/GRAY
Scab
Water-soaked spots on glumes followed by pink to reddish fluffy mycelial growth along edge of glumes; spikelets are prematurely bleached; blue-black perithecia may develop on glumes and kernels near harvest
BROWN
Bacterial leaf blight
Tan to dark brown necrotic spots on side of kernels
Bacterial leaf streak
Brown, water-soaked lesions or, glumes
Basal glume rot
Brown discolored area near base of glumes
Black point
Embryo end of kernels dark brown to black
Spot blotch
Round to oblong lesions of a uniform brown color, with a definite margin; spots may coalesce to form large blotches; heads and kernels may also be attacked
DARK
Anthracnose
Lesions above the below ground on the lower portions of the culm, at first water-soaked then bleached and necrotic; dark acervuli with dark microscopic spines in lesions; severe infection causes lodging and head blight
Black point
Embryo end of kernels dark brown to black
Powdery mildew
Superficial cottony mycelial growth on leaves and sometimes heads; dark fruiting bodies develop within mycelium with age; colonies develop a powdery appearance as conidia develop on the mycelium
PINK
Scab
Water-soaked spots on glumes followed by pink to reddish fluffy mycelial growth along edge of glumes; spikelets are prematurely bleached; blue-black perithecia may develop on glumes and kernels near harvest
PURPLE
Ergot
Purple-black, hornlike growth in the heads, replacing the seed
RED
Scab
Water-soaked spots on glumes followed by pink to reddish fluffy mycelial growth along edge of glumes; spikelets are prematurely bleached; blue-black perithecia may develop on glumes and kernels near harvest
Stem rust
Brick red pustules with ragged edges on stems and leaf sheaths, sometimes on leaves, glumes and awns
TAN
Bacterial leaf blight
Tan to dark brown necrotic spots on side of kernels
WHITE
Cephalosporium stripe
Yellow leaf stripes with dark brown vascular bundles within the yellow stripe; plant is often stunted with white heads
Semiloose smut
Delicate membrane surround powdery, chocolate-brown spores and eventually fragments, releasing the spores; the naked rachis of the head remains
Take-all
Plants are stunted, often with white heads; roots break off when plants are pulled from the ground; roots are brittle and black, with black runner hyphae on root surface; base of culm is often covered with black mass of mycelium
YELLOW
Aster yellows
Chlorotic blotches coalesce to cause general yellowing; leaves tend to roll inward; plant is severely stunted, often without heading; phyllody often results (if heads or produced), with twisted awns
Stripe rust
Yellow pustules in long linear stripes primarily on leaves but sometimes on stems, glumes, and awns
No Distinct Discoloration
2,4-D; MCPA
Twisted spikes, double heads
Barley stripe
Longitudinal yellow stripes on seedling leaves, extending to all leaves; leaves eventually become necrotic and tend to shred and fray at the ends; infected plants are stunted, and spikes fail to emerge or become twisted, blighted, or compressed
Dwarf bunt
Plants are severely stunted, with bunt balls replacing the seed; characteristic fishy odor when bunt balls are broken open
Frost
Sterile florets in head; water-soaking at base of peduncle
Glume blotch
Brown to gray spots on leaf blades and sheaths, later becoming oval or lens-shaped, red-brown spots with chlorotic tissue along the leaf veins; pycnidia often found in the lesions; later, spots develop on glumes and awns
Picloram
Twisted heads; prostrate, reduced growth
Potassium deficiency
Dwarfed shoots with short internodes; excessive tillering with few heads
Powdery mildew
Superficial cottony mycelial growth on leaves and sometimes heads; dark fruiting bodies develop within mycelium with age; colonies develop a powdery appearance as conidia develop on the mycelium
True loose smut
Delicate membrane surrounds powdery, olive-brown spores and eventually fragments, releasing the spores; the naked rachis of the head remains