Diseases of Barley - Fungal

 
 
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 Common Root Rot | Fusarium Head Blight | Semi-loose Smut or False Loose Smut | Covered Smut | Loose Smut | Ergot | Leaf Stripe | Net Blotch | Spot Form of Net Blotch | Scald | Speckled Leaf Blotch | Spot Blotch | Stem Rust | Powdery Mildew | Browning Root Rot | Black Point

Common Root Rot.
Cochliobolus sativus, Fusarium spp.

What to look for?
When barley is grown after barley a build-up of soil-borne root rot spores occur which can seriously affect seedling establishment. Older plants show damaged crown and roots which reduce yield and quality in the diseased crop. In wet humid seasons the disease can move up into the leaves, even affecting the head and downgrading the grain quality.

Light brown discolouration of the crown and subcrown internodes.
Photo: Duczek
Picture description
Light brown discoloration of the crown and subcrown internodes.
Healthy seedling on left and root rot infested seedlings on right.
Photo: Evans
Picture description
Healthy seedling on left and root rot infested seedlings on right.

Management strategy
Cochliobolus is the main problem--crop rotation of a few years with seed treatments and balanced fertility give control.

A more complete description of common root rot in barley.

Fusarium Head Blight of Barley
Fusarium graminearum (F. poae, F. sporotrichoides, F. Avenaceum and F. culmorum)

What to look for?
In barley cultivars Fusarium Head Blight or scab is much less obvious than in infected wheat crops. Again several species of Fusarium will cause typical blight symptoms but only F. graminearum produces the toxins. Infected barley spikelets do not show up as well as in wheat, oats or rye. In malting there is a zero tolerance for this fungus. Barley like wheat is susceptible for a 2 week period around heading and anthesis.

For a more complete description look under Fusarium Head Blight of Barley and Wheat (FS110/632-1) and
Fusarium Head Blight (FHB), Scab, Pink Mold or White Heads in barley.
Alberta Fusarium graminearum Management Plan
Fusarium FAQ

Semi-loose Smut and False Loose Smut
Ustilago nigra

What to look for?
Look for black sooty heads to emerge from the boot stage before the healthy grain heads. Ustilago nigra is known as semi-loose smut and affected plants are shorter than healthy plants. Infectious spores lodge onto the surface of healthy barley grains on adjacent heads or they may germinate and grow as mycelium which stays dormant under the barley hull.

Smutted heads emerge from the boot a day or so before the healthy heads.
Photo: Thomas
Picture description
Smutted heads emerge from the boot a day or so before the healthy heads.
.
Management strategy
Use resistant cultivars or a contact or systemic fungicide seed treatment.

A more complete description of smut in barley.

Covered Smut.
Ustilago hordei

What to look for?
Covered smut does not show up very well on infected barley heads until 2 - 3 weeks after head emergence. To see infected heads you have to look closely into the barley crop. During combining the covered smut heads break-up and infectious spores infest healthy barley grains.

Infected barley heads.
Photo: Duczek
Picture description
Infected barley heads.
Infected barley heads.
Photo: Evans
Picture description
Infected barley heads.
Covered smut in barley.
Photo: Evans
Picture description
Covered smut in barley.
.
Management strategy
A contact or systemic seed treatment will give excellent control killing the infectious spores on the outside of the healthy grains.

A more complete description of smut in barley.

Loose Smut.
Ustilago nuda

What to look for?
Loose smutted heads of barley like the semi-loose smut emerges a few day before the healthy heads. The loose smut spores germinate on the flowering barley heads and grow into the embryos of the infested grains.

Loose smut fungus Mycelium grows into the barley embryo as depicted on the right.
Photo: Unknown
Picture description
The loose smut fungus Mycelium grows into the barley embryo as depicted on the right.
Spores shed easily from the loose smutted head.
Photo: Evans
Picture description
Spores shed easily from the loose smutted head.
.
Management strategy
An effective systemic fungicide must be used to control this fungal disease. Field infections of loose smut can range from trace levels to over 50% of plants.

A more complete description of smut in barley.

Ergot.
Claviceps purpurea

What to look for?
Ergots show up in mid- to late-August as obvious back bodies on the barley heads. Ergot infection in barley is a high indication of copper deficiency which results in pollen sterility--see Ergot of wheat and copper deficiency in barley.

Copper fertilizers in such instances not only get rid of the ergots but improve the crops resistance to lodging, and greatly increase yield and grain quality.

Late spring frosts and severe summer drought may occasionally be responsible for ergot infection - i.e. a kill-off of pollen forcing the barley florets to open exposing them to ergot infection. Barley, wheat and oats are normally self-pollinated and are never open-pollenated like rye. Certified cultivars of these grains may be grown side by side since cross pollination does not occur.

Severe boron deficiency in Finland and Quebec can also result in ergot infection in barley. In the absence or severe deficiency of boron the pollen tubes fail to maintain their integrity in moving down the barley stigmas and results in pollenation failure. The unfertilized flowers then open hoping for stray viable pollen again exposing the stigmas to ergot infection.

A heavily ergot infected head of barley.
Photo: Duczek
Picture description
A heavily ergot infected head of barley.
Ergots and healthy barley grain.
Photo: Evans
Picture description
Ergots and healthy barley grain.
Ergots germinate in late spring and early summer producing mushroom-like structures that release infectious ascospores.
Photo: Unknown
Picture description
Ergots germinate in late spring and early summer producing mushroom-like structures that release infectious ascospores.
.
Management strategy
Adequate copper fertility either foliar or soil applied in western Canada or adequate boron fertility in Quebec will greatly enhance yield and grain quality and reduce or prevent crop lodging. Copper is an essential enzyme component in the production of lignin and hence straw strength in cereal crops.

A more complete description of ergot in barley.

Leaf Stripe.
Pyrenophora graminea

What to look for?
Bold brown-striped leaves especially the upper leaves on scattered plants. Diseased plants are soon lost in the healthy canopy since infected plants remain stunted. Infection levels range from a trace up to 40% on some susceptible cultivars.

Dwarfed stripe infected plants.
Photo: Davidson
Picture description
Dwarfed stripe infected plants.
Distinctly striped leaves show up at the second or third leaf stage.
Photo: Evans
Picture description
Distinctly striped leaves show up at the second or third leaf stage.
Stripe fungus kills off infected plants leaving empty heads.
Photo: Evans
Picture description
Stripe fungus kills off infected plants leaving empty heads.
.
Management strategy
Systemic seed treatment should be used since in infected seed the fungus mycelium is lodged between the hull and the grain.

A more complete description of leaf stripe in barley.

Net Blotch.
Pyrenophora teres

What to look for?
Typical brown netting or just brown spots may show up on the second or third leaf of seedlings. In warm humid seasons on susceptible cultivars the fungus can infect the upper leaves and even the heads causing considerable yield and quality loss. This disease is most prevalent in the southern prairies.

Brown streaks on infected leaves.
Photo: Tekauz
Picture description
Brown streaks on infected leaves.
Early net infection on the flag leaves.
Photo: Evans
Picture description
Early net infection on the flag leaves.
Typical net-type damage.
Photo: Evans
Picture description
Typical net-type damage.
Severely netted flag leaf.
Photo: Evans
Picture description
Severely netted flag leaf.
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Management strategy
The fungus survives on crop residues and on seed. Seed treatment, resistant cultivars and crop rotation as well as timely application of foliar fungicides give good disease control.

A more complete description of net blotch in barley.

Spot Form of Net Blotch.
Pyrenophora teres

What to look for?
Distinct brown spots unlike that of the more typical brown net-type lesions.

Numerous distinct brown spots instead of the net-like infections.
Photo: Tekauz
Picture description
Numerous distinct brown spots instead of the net-like infections.
.
Management strategy
The fungus survives on crop residues and on seed. Seed treatment, resistant cultivars and crop rotation as well as timely application of foliar fungicides give good control.

A more complete description of the spot form of net blotch in barley.

Scald
Rhynchosporium secalis

What to look for?
This disease is more typical of barley in the cooler northerly areas of the prairies. Large leaf areas with water soaked lesions that rapidly turn brown generally showing up at the 5th or 6th leaf stage in wet cool seasons. In cold wet seasons scald can cause losses of up to 50% or more in yield and quality loss.

Scald lesions.
Photo: Duczek
Picture description
Scald lesions.
Scalded flag leaves.
Photo: Evans
Picture description
Scalded flag leaves.
.
Management strategy
Both scald and net blotch must be carefully watched particularly in malt barley crops. Seed treatment, crop rotation, resistant cultivars and foliar fungicides are all important in malt barley management strategies.

A more complete description of scald in barley.

Speckled Leaf Blotch.
Septoria passerinii

What to look for?
This disease usually shows up late in the season in cold wet Augusts and is often mistaken for leaf senescence. Look for the pepper-like spots on the flag leaves.

Pepper-like spots on the elongate brown lesions.
Photo: Duczek
Picture description
Pepper-like spots on the elongate brown lesions.
.
Management strategy
In areas prone to this disease follow a crop rotation and the fungicides used for the control of scald and net blotch can give control of leaf blotch.

A more complete description of speckled leaf blotch in barley.

Spot Blotch.
Cochliobolus sativus

What to look for?
This common root rot fungus is usually confined to the roots, crowns and leaves on the prairies. In wet seasons the fungus may move all the way up to the barley heads as is common in Eastern Canada. Yield and quality loss result.

Diffuse brown spots of this fungus that can occur on upper leaves and glumes.
Photo: Duczek
Picture description
Diffuse brown spots of this fungus that can occur on upper leaves and glumes.
.
Management strategy
Seed treatment and crop rotation will reduce incidences of spot blotch and foliar fungicides for control of scald or net blotch will suppress this disease.

A more complete description of spot blotch in barley.

Stem Rust.
Puccinia graminis f.sp. secalis & f.sp. tritici

What to look for?
Stem rust will show up on barley in the same years--see stem rust of wheat. A very distinct rust on the stems of barley that rarely occurs in Alberta.

Distinct red rust on the stems and leaves.
Photo: Tekauz
Picture description
Distinct red rust on the stems and leaves.
.
Management strategy
This disease just like the stem rust of oats and wheat arrives mid- to late-season to be of any consequence to Alberta and western Saskatchewan barley crops.

A more complete description of stem rust in barley.

Powdery Mildew.
Erysiphe graminis

What to look for?
Look well into the canopy of a barley crop in mid-August especially in hot, humid rather than wet conditions and powdery mildew either white or grayish will be present on the lower leaves.

On some cultivars the mildew will appear on the flag leaf. The heavy brown flecks on some barley cultivars (leaves) may be due to a mildew resistant reaction.

Characteristic fluffy white to grayish mildew usually on the surface of the lower leaves.
Photo: Tekauz
Picture description
Characteristic fluffy white to grayish mildew usually on the surface of the lower leaves.
.
Management strategy
Most barleys are resistant to this disease--where it is a problem foliar fungicides will give control. In eastern Canada powdery mildew can be a very destructive disease.

A more complete description of powdery mildew in barley.

Browning Root Rot.
Pythium spp.

What to look for?
Uneven growth of the barley crop with poor vigor and weak stems.

Patches of unthrifty plants.
Photo: Piening
Picture description
Patches of unthrifty plants.
Stunted vs healthy plants.
Photo: Piening
Picture description
Stunted vs healthy plants.
.
Management strategy
Pythium spp. are associated with this disease but adequate phosphate fertility seems to eliminate this disease as a problem.

A more complete description of browning root rot in barley.

Black Point.
Alternaria spp. Cochliobolus sativus, Fusarium spp.

What to look for?
Look for barley crops that have had dry springs and wet summers. Head of barley may be still in the sheath due to the earlier dry growing conditions. This partial enclosure holds moisture typically resulting in black point grain.

Distinct black points unacceptable for malting.
Photo: Evans
Picture description
Distinct black points unacceptable for malting.
.
Management strategy
In irrigated barley do not allow the crops to dry out at heading--so that the heads are well clear of the sheaths. Foliar fungicides may help in some years. Avoid growing barley after barley.

Photographs and information assembled and prepared for ARD by Dr. Ieaun R. Evans Agri-Trend Agrology Ltd.
 
 
 
 

Other Documents in the Series

 
  Diseases of Barley - Bacteria and Phytoplasma
Diseases of Barley - Fungal - Current Document
Diseases of Barley - Non-Infectious
Diseases of Barley - Viral
 
 
 
 
For more information about the content of this document, contact Robert Spencer.
This document is maintained by Shelley Barkley.
This information published to the web on December 1, 2003.
Last Reviewed/Revised on December 8, 2010.