Barley:Key

KEY TO BARLEY 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

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