Barley

Description

Barley, Hordeum vulgare, is an edible annual grass in the family Poaceae grown as a cereal grain crop. It is a tall grass with a hairy stem which stands erect and produces spikelets at the head. The stem is made up of nodes and internodes. The internodes are solid, whereas the internodes are hollow. The stem supports the inflorescence, or spike, where the grain is produced. Barley seeds heads are cylindrical spikes composed of rachis each with 3 spikelets. Each spike produces 20–60 grains. Barley plants are freely tillering and typically possesses 1–6 stems. The tillers do not produce seed heads. Barley is an annual plant which is harvested each year and it can range in height from 80 to 100 cm (31.5–39.4 in). Barley may be referred to as spring barley or winter barley and it was first domesticated in the Fertile Crescent of the Middle East.


Uses

Barley is cultivated as a food cereal in the tropics and subtropics in India, Nepal, Tibet, Afghanistan, Russia, Ethiopia, North Africa and the Andean region of South America. The straw produced is used as an animal feed, bedding and to cover roofs of houses. In temperate regions, barley is used in malt production to brew beer and make other distilled alcoholic beverages, particularly whisky.


Propagation

Barley varieties
Like wheat, barley can be grown in Spring or Fall. Barley can be classed as either six-rox or two-row. Two-row barley has two rows of seeds on each spike whereas six-row barley has six rows of seeds on each spike. Two-row barley varieties tend to be spring grown whereas six-row barley varieties include both spring and winter grown types.

Planting
Winter barley varieties should be planted in the Fall approximately 6 to 8 weeks before the first frost date. Spring varieties should be planted as soon as the soil can be worked in the Spring. Barley requires temperatures to have reached a minimum of 1–2°C (34–36°F) for successful germination. Seeds should be sown in prepared seed bed in rows or by broadcasting. Commercially grown barley is usually mechanically drilled using a machine that creates a furrow and drops the seed in before covering it back up. Seeds are usually sown to depths ranging from 2 to 12 cm (0.8–4.7 in) depending on soil conditions (seed must be sown deeper in drier soil) and the soil should be raked lightly after planting. Spring barley varieties usually reach maturity in 60 to 80 days and winter barley in 60 days.

Harvesting
Barley is ready to harvest when the stalks and heads have turned from green to yellow and the seed heads are drooping towards the ground. Check the seeds for ripeness before harvest. The should be firm and crunchy and not doughy in texture. Commercially produced wheat is usually harvested using a combine. Smaller plots can be harvested by hand using a scythe or sickle. Small plots can be harvested by snipping off the heads with a pair of scissors.


References

Anderson, P. M., Oelke, E. A. & Simmons, S. R. (2013). Growth and development guide for spring barley. University of Minnesota Extension. Available at: http://www.extension.umn.edu/agricult.... [Accessed 06 November 14]. Free to access.

CABI Crop Protection Compendium. (2011). Hordeum vulgare datasheet. Available at: http://www.cabi.org/cpc/datasheet/27662. [Accessed 06 November 14]. Paid subscription required.

Mathre, D. E. (Ed.) (1997). Compendium of barley diseases. Available at: http://www.apsnet.org/apsstore/shopap.... Available for purchase from APS Press.

McVay, K., Burrows, M., Jones, C., Wanner, K. & Menalled, F. Montana barley production guide. Montana State University Extension. Available at: http://store.msuextension.org/publica.... [Accessed 06 November 14]. Free to access.


Common Pests and Diseases

Bacterial blight (Bacterial leaf blight, Black chaff)
Xanthomonas translucens also known as Xanthomonas campestris

Symptoms
Water soaked spots on foliage; shriveling dead leaves; glossy yellow or brown streaks; plant appears stunted, slow plant growth.
Cause
Bacteria
Comments
Occurs wherever barley is grown.
Management
Use only certified, disease-free seed; treat seeds with a fungicide prior to planting to prevent diseases which allow bacteria to enter easily; practice crop rotation to reduce disease build-up in soil.

Basal glume rot
Pseudomonas syringae

Symptoms
Brown discoloration at base of the glume (bract covering the kernel); dark line where glume attaches to spike; water soaked spots on leaves; yellow and necrotic spots on leaves.
Cause
Bacterium
Comments
Occurs wherever barley is grown; spread by seed.
Management
Treat seeds with a fungicide prior to planting to prevent diseases which allow bacteria to enter easily; practice crop rotation to reduce disease build-up in soil; plow crop residue into soil.

Common root rot
Bipolaris sorokiniana
Cochliobolus sativus
Fusarium culmorum
Fusarium graminearum

Symptoms
Brown lesions on leaves nearest soil extending to stem; resembles drought; death of lower leaves; rotting roots.
Cause
Fungi
Comments
Generally occurs wherever barley is grown but is more common in water stressed plants.
Management
No chemical treatments for this disease; plant crop in late fall to avoid warm soils which favor emergence of disease; do not fertilize crop excessively; use irrigation to reduce water stress.

Barley stripe
Pyrenophora graminea

Symptoms
Small yellow spots on seedling leaves; yellow to tan stripes along leaf blade before heading; red margins on stripes; death of diseased tissue; heads not emerging; plants stunted.
Cause
Fungus
Comments
Occurs wherever winter barley is grown.
Management
Use only certified seed.

Downy mildew
Sclerophthora rayssiae

Symptoms
Dwarfed and/or deformed plants; flag leaves yellow; leathery leaves; heads distorted; seed not formed.
Cause
Fungus
Comments
Occurs wherever winter barley is grown, usually after excessive rainfall.
Management
Plant crop in well-draining soils; control weeds in field which can act as reservoirs for the disease; sow seed only from disease free plants.

Ergot
Claviceps purpurea

Symptoms
Only head affected; flowers oozing sticky substance (honeydew); head appears dirty due to dust sticking to honeydew; diseased kernels turn to black mass of fungal mycelia.
Cause
Fungus
Comments
Not usually severe.
Management
Till crop residue deep into soil to prevent spores being released into the air; control weeds, especially grasses, in field which act as a secondary host for disease.

Eyespot (foot rot)
Pseodocercosporella herpotrichoides

Symptoms
Eye shaped lesions on basal leaf sheaths and stem; stems shriveled and/or collapsing; plants chlorotic; heads white and undersized.
Cause
Fungus
Comments
Widespread wherever barley is grown.
Management
Rotate barley with leguminous plants; sow spring barley which is more tolerant of spring frosts.

Covered smut
Ustilago hordei

Symptoms
Stunted growth; late emergence of heads; kernels replaced with grey fungal masses.
Cause
Fungus
Comments
Smut masses burst during harvest and further transmit disease; crushed spore masses have an odor similar to rotting fish.
Management
Use only certified smut-free seed; treat seeds with hot water prior to planting to kill fungi; treat seeds with contact fungicide; grow resistant varieties.

Loose smut
Ustilago nuda
Ustilago tritici

Symptoms
Early emergence of heads; dark green or black masses in place of kernels.
Cause
Fungus
Comments
Spores rupture out from protective membrane on heads; fungus can survive in infected seed.
Management
Use only certified smut-free seed; treat seeds with hot water prior to planting to kill fungi; treat seeds with systemic fungicide (fungi inside seed) fungicide; grow resistant varieties.

Net blotch
Pyrenophora teres

Symptoms
Dark green water soaked spots; narrow brown blotches with netted appearance, surrounding tissue yellow; stripes running the length of leaf.
Cause
Fungus
Comments
High humidity promotes spread of the disease.
Management
Rotate barley with resistant crops; grow resistant varieties; remove and crop residue from soil surface; destroy volunteer barley plants.

Fusarium head blight (FHB or scab)
Fusarium graminearum

Symptoms
Initial symptoms show bleaching of some of the florets in the spike. Under favorable conditions, premature blight or bleaching of whole spike may occur. As the disease progress head turns tan to brown discoloration. Also, we can see pink or orange color mold appears at the base of the florets. The kernels become shriveled, white, and chalky.
Cause
Fungus
Comments
Since the pathogen infects kernel, the disease causes high yield loss, low test weights and low seed germination. Another major problem is pathogen produces mycotoxin, deoxynivalenol (DON) which is an vomitoxin.
Management
Grow available resistant varieties. If the disease is severe, spray suitable fungicide.

Powder mildew
Blumeria graminis

Symptoms
Initially the lower leaf surface shows white, cottony patches of fungal growth. The upper surface of these patches exhibit chlorotic spots. As the disease progress, this white cottony patches become dull gray- brown color due to development of fruiting bodies (cleistothecia). The infected plants show slow growth.
Cause
Fungus
Comments
The pathogen is common in fields with high plant density, application of high nitrogen fertilizers, high relative humidity, and cool weather.
Management
Grow available resistant varieties. Follow crop rotation. Keep the field free from weeds and other unwanted plants. Remove and destroy the infected crop residue.

Leaf Scald
Rhynchosporium secalis

Symptoms
Appearance of dark, pale or bluish gray lesions on leaves. As the disease progress, these spots enlarge into oval lesions with bluish gray centers and dark brown margins. The spots may join together and appear like rapid scalding.
Cause
Fungus
Comments
Disease is transmitted by water splash and infected seeds.
Management
Use disease free seeds. Grow available resistant varieties. Follow crop rotation. Remove and destroy the infected crop residue. Keep filed free from weeds and other crop plants.

Armyworms (Armyworm, Western striped armyworm)
Mythimna unipunctata
Spodoptera praefica

Symptoms
Entire leaves consumed; notches eaten in leaves; egg clusters of 50-150 eggs may be present on the leaves; egg clusters are covered in a whitish scale which gives the cluster a cottony or fuzzy appearance; young larvae are pale green to yellow in color while older larvae are generally darker green with a dark and light line running along the side of their body and a pink or yellow underside.
Cause
Insect
Comments
Insect can go through 3–5 generations a year.
Management
Organic methods of controlling armyworms include biological control by natural enemies which parasitize the larvae and the application of Bacillus thuringiensis; there are chemicals available for commercial control but many that are available for the home garden do not provide adequate control of the larvae.

Stinkbugs
Euschistus spp.

Symptoms
Damage to head during milk or soft dough stage; stink bugs often carry pathogens in their mouthparts which can cause secondary infections; adult insect is shield-shaped and brown or green in color; may have pink, red or yellow markings; eggs are drum shaped and laid in clusters on the leaves; larvae resemble the adults but are smaller.
Cause
Insect
Comments
Adult insects overwinter under leaves, on legumes, blackberries or on certain weeds such as mustard or Russian thistle.
Management
Remove weeds around crop which may act as overwintering sites for stink bugs and practice good weed management throughout the year; organically accepted control methods include the use of insecticidal soaps, kaolin clay and preservation of natural enemies.

Wireworms
Aeolus spp.
Anchastus spp.
Melanotus spp.
Limonius spp

Symptoms
Death of seedlings; reduced stand; girdled stems and white heads; wireworm larvae can be found in soil when dug round the stem; larvae are yellow-brown, thin worms with shiny skin.
Cause
Insect
Comments
Larval stage can last between 1 and 5 years depending on species.
Management
Chemical control impossible in a standing crop, must be applied at preplanting or as a seed treatment; if wireworms are known to be present in soil fallow field during summer and till frequently to reduce numbers; rotate to non-host crop where possible; avoid planting susceptible crops after a wireworm infestation on cereals without either fallowing of applying appropriate pesticide.

Aphids (Bird cherry-oat aphid, Russian wheat aphid, Corn leaf aphid, etc.)
Rhopalosuphum padi
Diuraphis noxia
Sitobion avenae

Symptoms
Yellow or white streaked leaves; flag leaves may be curled up; plants may be stunted and tillers may lie parallel to the ground; plants may turn a purple color in cold weather; insects are small and soft-bodied and may be yellow, green, black or pink in color depending on species; insects secrete a sugary substance called "honeydew" which promotes the growth of sooty mold on the plants.
Cause
Insect
Comments
Fields should be checked for aphid populations periodically after emergence.
Management
Sturdy plants can be sprayed with a strong jet of water to knock aphids from leaves; insecticides are generally only required to treat aphids if the infestation is very high - plants generally tolerate low and medium level infestation; insecticidal soaps or oils such as neem or canola oil are usually the best method of control; always check the labels of the products for specific usage guidelines prior to use; in commercial plantations aphid numbers are usually kept in check by predators and natural enemies; beneficial insect populations should be assessed before chemical control is considered; if no beneficial insect populations are present and aphids are damaging then apply appropriate insecticides.

Barley mealybug (Haanchen mealybug)
Trionymus haancheni

Symptoms
Both nymphs and adults suck the sap from leaves and stem resulting in yellowing and browning. Heavy infestation leads to a reduction in growth. Mealybug secrets honey dew which results in sooty mold development.
Cause
Insect
Comments
Appearance of white cottony mass near the base barley stem indicates mealybug infestation.
Management
Encourage natural enemies. If infestation is severe spray suitable insecticide.

Barley yellow dwarf
Barley yellow dwarf virus (BYDV)

Symptoms
Stunted growth of plants; yellow green blotches at leaf tip, leaf margin or leaf blade; leaves turning bright yellow, red or purple.
Cause
Virus
Comments
Transmitted by aphids; symptoms more apparent in colder temperatures.
Management
Grow resistant or tolerant varieties; avoid planting crop very early or very late when aphid populations are high.