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.
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.
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.
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.
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.
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.
Fields should be checked for aphid populations periodically after emergence.
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.
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.
Insect can go through 3–5 generations a year.
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.
Water soaked spots on foliage; shriveling dead leaves; glossy yellow or brown streaks; plant appears stunted, slow plant growth.
Occurs wherever barley is grown.
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.
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.
Appearance of white cottony mass near the base barley stem indicates mealybug infestation.
Encourage natural enemies. If infestation is severe spray suitable insecticide.
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.
Occurs wherever winter barley is grown.
Use only certified seed.
Stunted growth of plants; yellow green blotches at leaf tip, leaf margin or leaf blade; leaves turning bright yellow, red or purple.
Transmitted by aphids; symptoms more apparent in colder temperatures.
Grow resistant or tolerant varieties; avoid planting crop very early or very late when aphid populations are high.
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.
Occurs wherever barley is grown; spread by 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; plow crop residue into soil.
Brown lesions on leaves nearest soil extending to stem; resembles drought; death of lower leaves; rotting roots.
Generally occurs wherever barley is grown but is more common in water stressed plants.
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.
Stunted growth; late emergence of heads; kernels replaced with grey fungal masses.
Smut masses burst during harvest and further transmit disease; crushed spore masses have an odor similar to rotting fish.
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.
Dwarfed and/or deformed plants; flag leaves yellow; leathery leaves; heads distorted; seed not formed.
Occurs wherever winter barley is grown, usually after excessive rainfall.
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.
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.
Not usually severe.
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.
Eye shaped lesions on basal leaf sheaths and stem; stems shriveled and/or collapsing; plants chlorotic; heads white and undersized.
Widespread wherever barley is grown.
Rotate barley with leguminous plants; sow spring barley which is more tolerant of spring frosts.
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.
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.
Grow available resistant varieties. If the disease is severe, spray suitable fungicide.
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.
Disease is transmitted by water splash and infected seeds.
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.
Early emergence of heads; dark green or black masses in place of kernels.
Spores rupture out from protective membrane on heads; fungus can survive in infected seed.
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.
Dark green water soaked spots; narrow brown blotches with netted appearance, surrounding tissue yellow; stripes running the length of leaf.
High humidity promotes spread of the disease.
Rotate barley with resistant crops; grow resistant varieties; remove and crop residue from soil surface; destroy volunteer barley plants.
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.
The pathogen is common in fields with high plant density, application of high nitrogen fertilizers, high relative humidity, and cool weather.
Grow available resistant varieties. Follow crop rotation. Keep the field free from weeds and other unwanted plants. Remove and destroy the infected crop residue.
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.
Adult insects overwinter under leaves, on legumes, blackberries or on certain weeds such as mustard or Russian thistle.
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.
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.
Larval stage can last between 1 and 5 years depending on species.
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.
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.