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Crop Profile forBarley

in Washington

Production Facts

❖ Washington ranked fourth during 1999 in the US in barley produc-tion with 10.3% of the US crop (1).

❖ 500,000 acres were planted and 490,000 were harvested in 1999yielding 28,910,000 bushels with an estimated value of $51 million (1).

❖ Crop value per harvested acre was $104 in 1998 (1).

❖ While production costs vary considerably with rainfall and otherfactors, a ten-year study shows a per acre average of $187 ($116 variable,$71 fixed); this study showed a value per acre of $113 (3).

❖ Barley’s value to Washington growers is primarily in its function asa useful rotation tool between more profitable crops. The economics ofgrowing barley make affordable pest control extremely important.

❖ 92% of the 1999 planting was made up of feed barley varieties and8% were malting varieties (1).

❖ End use for Washington barley is primarily feed (beef and dairycattle, swine and poultry production) at 92% and malting (food, beer,beverages) at 8% (4).

ProductionRegionsBarley is grownin every countyin Washington,but concentratedproduction islocated in five

LincolnAdams

SpokaneGarfield

Whitman

eastern Washingtoncounties.

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General Information

Barley is a cool-weather cereal grainprimarily produced on dryland farms inWashington (a small portion—less than 5%—isgrown under irrigation). Over 95% of the barleygrown in Washington is spring barley, which isplanted in early spring (generally April) andharvested in late July or August of the same year.Washington’s winter barley is seeded in Septemberor October and harvested in late July or August ofthe following year.

The preponderance of spring barleycan be attributed to two factors: it is a lessrisky crop than winter barley and it primaryfunctions as a rotation crop with winterwheat. None of the barley varieties grown inWashington are extremely winter-hardy; aharsh winter can dramatically reduce or evenobliterate yield. Traditionally, winter barleyhad higher yields (due in large part to alonger growing period), but the newervarieties of spring barley introduced in theearly 1990s yield just as well. Because barleyfunctions as a rotation crop with winterwheat, the spring barley cycle is a good fit.Barley matures early, uses less water thanwheat, and has a short life cycle, allowingrotation to the more profitable winter wheator even, in high rainfall areas, a triplerotation following wheat and preceding alegume (pea/lentil) crop.

Both two-row and six-row barleyvarieties are grown in Washington (seeFigure 1). A six-row variety called Steptoe,developed in the 1970s , was the statestandard for years, but has been largelyreplaced by a high-performing, two-rowimported variety called Baronesse. A grower’schoice of two-row or six-row depends uponenvironment, climate, and available varieties;either can be used for the three primarymarkets: animal feed, malting, or humanfood.

Animal feed is by far the dominantmarket for Washington barley. Two-rowbarley varieties tend to result in higher “test

weight,” an important factor in the feed market.Malting, a market with very specific productstandards and specifications, comprises about 12%of Washington barley sales. Less than one percentof Washington’s barley is grown for humanconsumption. A number of different types, such ashulless, awnless, and waxy allow growers differentniche markets.

FIGURE 1

Two-row and six-row barley.

Figures courtesy of Washington Barley Commission (4).

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Cultural Practices

Washington barley is generally grown inrotation with wheat, with the typical rotation be-ing (more profitable) winter wheat followed by(less profitable) spring barley. In higher rainfallareas, a legume crop may follow spring barley.Other crops including potatoes may be part ofsome rotations.

Seedbed preparation for barley is minimal.Residues of the previous crop are usually partiallyincorporated but not totally plowed under; a pris-tine seedbed is not necessary. Direct seeding ispracticed on some acreages, in which case there isno seedbed preparation. Barley’s own residuebreaks down very well compared to other cerealcrops; it is very rarely burned but may be disked orotherwise plowed under.

Barley has low moisture requirements. It canbe grown in as few as 11 to 12 inches of annualrainfall and can tolerate less moisture under “no-till” (direct seeding) systems. A summer fallowsystem (land left idle during a growing season)conserves enough moisture in the soil to enableproduction in some situations where rainfall is aslow as 6 to 7 inches annually.

Washington barley growers use registered,certified seed, some of which is grown in the state.Most barley is produced for the open market.Malting barley is the exception, it is grown undercontract.

Because of narrow profit margins and lowreturns on barley, chemicals are not used exten-sively for pest control. In some cases, chemical usecould be effective, but is precluded by simple eco-nomics. New, cost-effective pest control optionsare needed for barley.

Pests are listed in the order of importance,with weeds being the most important followed bydiseases, then insects.

Weeds

Weeds are the most important class of barleypests in Washington State. Costs of control andlosses due to weeds are greater than with any otherpests. Herbicides represent the greatest amount ofpesticides applied to Washington barley in terms ofamount of active ingredient applied and percent-age of treated acres.

Generally, herbicide application timings canbe categorized as pre-plant, pre-emergence, post-emergence, or harvest aid.

Pre-plant applications often include the useof nonselective herbicides designed to controlweeds or volunteer grains present prior to plantingbarley. Pre-plant applications of nonselective herbi-cides may replace the use of a tillage operation tokill vegetation, thereby reducing moisture lossfrom the soil and soil erosion due to tillage opera-tions. Other types of pre-plant herbicides will se-lectively control weeds as they emerge. Usuallythese herbicides will require mechanical incorpora-tion with a disk, cultivator, or some other tillagetool to activate the herbicide.

Pre-emergence herbicides are applied afterthe crop is planted, but prior to emergence ofcrops and weeds. Usually, the herbicides are ap-plied to the soil surface, but may be incorporatedinto the soil above the seeded crop using a lightharrow.

Post-emergence herbicides are applied fol-lowing emergence of the crop and weeds. Mostselective herbicide applications in barley are madeat this timing. The products that are most effectivefor weed management and cause the least amountof injury to the crop will vary depending upon thedevelopment stage of the barley crop.

Harvest aid herbicide applications are madeapproximately two weeks prior to harvest. Theseapplications have two purposes. They are designedto kill weeds so that by the time of harvest theweeds have dried out and will not interfere withthe harvest operation and to ensure that weed partsdo not affect the quality of harvested grain. Whilea harvest aid application will not increase yield ofthat year’s barley crop, it can reduce or preventseed production of the target weed, resulting in a

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net decrease of the soil weed seed bank. Ulti-mately, most of the annual weeds in a field origi-nate from seed that was produced in that fieldrather than immigrating from outside the field.

Generally, weed management strategies aredevised for specific annual grasses and annualbroadleaf weeds. The annual grass weed causingthe greatest problem in Washington barley is wildoat (Avena fatua). The particular annual broadleafspecies of importance vary greatly throughout thestate, determined by the local climate and produc-tion practices, such as tillage systems and croprotations. Problems besides wild oat may includeRussian thistle (Salsola spp.), mayweed chamomile(Matricaria spp.), common lambsquarters (Che-nopodium album), dog fennel (var. Matricaria andAnthemis spp.), Italian ryegrass (Loliummultiflorum), and prickly lettuce (Lactuca serriola).Green and yellow foxtails (Setaria viridis and Se-taria glauca) are common barley pests in the GreatPlains, but, while present in Washington, have notposed a pest problem to date.

Perennial weeds, considered a long-termproblem, are managed throughout the crop rota-tion by combinations of tillage and herbicide treat-ments. Those most pestiferous in barley are fieldbindweed (Convolvulus arvensis), Canada thistle(Cirsium arvense), and quackgrass (Elymus repens).Barley is considered the greatest competitive cropof most rotations and is included in rotations forthis reason.

Controls

BiologicalBiological control has not effectively and

consistently controlled any of the species of weedsknown to be chronic problems in barley.

Integrated Weed ManagementBarley is used as a rotational weed manage-

ment tool in eastern Washington. Integrating thecompetitive abilities of barley along with mechani-cal and chemical control effectively reduces theoverall chemical use in barley and in the otherrotational crops. Specifically, barley in the rotationtends to reduce populations of annual grasses suchas wild oat and Italian ryegrass in a subsequent

rotation to wheat (or another cereal). Culturalcontrols such as crop rotation are widely practicedamong growers to reduce the amount of weeds.Mechanical weed control such as tilling the fieldsto control weeds prior to planting controls nearlyall annual weeds present and greatly reduces thegrowth of perennial weeds. Growers balance thisbenefit against the detriment of excessive tillagethat results in soil erosion.

Chemical

Triallate (Far-Go, Buckle) is used on 26%of barley acreage in eastern Washington for pre-emergence control of wild oat. The emulsifiableconcentrate (EC) must be mechanically incor-porated into the soil, therefore is not effective in“no-till” (direct-seeded) cropping systems. Resis-tant populations of weeds may develop. Far-Go isgenerally used at 1.25 lbs. a.i./A. The granularformulation is applied at 1.0-1.5 lbs. a.i./A. Buck-le, which combines triallate with trifluralin, is usedat a rate of 10 to 12.5 lbs. product/A.

Thifensulfuron (Harmony) is an amino-acid-synthesis inhibitor effective on broadleafweeds. It is used on 24% of barley acreage in east-ern Washington. It may be applied when barley isin the two-leaf stage of growth until the flag leaf isvisible. Harmony GT (75% thifensulfuron) isapplied at 0.225-0.375 oz. a.i./A. Due to potentialfor resistance development, growers applythifensulfuron in combination with broadleaf her-bicides with different modes of action. Optimalperformance requires adequate soil moistures andtemperatures of 60°F or greater before, during, andimmediately following application. When tank-mixed with thifensulfuron, most graminicide activ-ity is not reduced. (Graminicides are herbicidesactive on graminoid, or grass-like vascular plants.)Thifensulfuron is packaged in formulation withmany other ingredients (e.g., Canvas when incombination with both metsulfuron andtribenuron methyl, Harmony Extra when in com-bination with tribenuron), so rate of applicationcan vary significantly, but never exceeds theequivalent of 0.45 oz. a.i./A.

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2,4-D and MCPA (amine and ester formu-lations) are effective for post-emergence control ofmany species of broadleaf weeds; they do not con-trol grass weeds. They also may be used as a pre-harvest aid to desiccate broadleaf weeds that couldinterfere with the harvest operation or as a spottreatment for perennial weeds. Fifteen percent ofbarley acreage in eastern Washington received ap-plications of 2,4-D and 22% received applicationsof MCPA. Application rate varies from 0.125 to1.0 lbs. a.i./A.There is no information available onthe usage of specific formulations (amine or ester).MCPA and 2,4-D are often mixed with herbicideswith other modes of action in an attempt to pre-vent or slow development of resistance. Applica-tions of 2,4-D or MCPA must be delayed untilthe crop is well developed to avoid damaging thecrop. This delay can increase infestations of weedscausing reduced barley stand and ultimately yield.Tank mixing 2,4-D or MCPA with certaingraminicides may reduce the activity of thegraminicide.

Bromoxynil (Buctril or Bronate), a photo-synthetic disrupter used on approximately 16% ofbarley acreage in eastern Washington, is effectivefor post-emergence control of many broadleafweeds. It may be applied to barley from emergenceto the boot stage of the crop. Bromoxynil is veryeffective on small weeds, but larger weeds mayescape control. Weeds emerging after abromoxynil application will not be controlled bythe herbicide. Bromoxynil is most commonly usedas the Bronate formulation (premixed withMCPA) or tank-mixed with other broadleaf herbi-cides. Bronate is typically applied at 0.25 to 0.375lbs. a.i./A for both bromoxynil and MCPA, whileBuctril is typically applied at 0.5 lbs. a.i./A. Whentank-mixed with bromoxynil, graminicide activityis not reduced.

Tribenuron (Express, Harmony Extra) is anamino-acid-synthesis inhibitor effective on broad-leaf weeds. Used on 12% of barley acreage in east-ern Washington, it may be applied when barley isin the two-leaf stage of growth until the flag leaf isvisible. Due to potential for resistance develop-ment, growers apply tribenuron in combination

with broadleaf herbicides with different modes ofaction. Optimal performance requires adequatesoil moisture and temperatures of 60°F or greaterbefore, during, and immediately following applica-tion. Express is applied at 0.125 to 0.25 lbs. a.i./A.More often, Harmony Extra is used, which ispremixed with thifensulfuron and results in lessa.i./A.

Clopyralid (Stinger) is effective on certainbroadleaf weeds in the Asteraceae family includingthistles, prickly lettuce, and mayweed chamomile;particularly effective as a spot treatment forCanada thistle. Used on less than 1% of the barleyacreage in eastern Washington. Use of this prod-uct may prevent planting susceptible crops such ascanola or mustard for a period of twelve months.Other clopyralid products that may be used in-clude Curtail (premixed with 2,4-D amine) andCurtail M (premixed with MCPA).

Dicamba (Banvel, Clarity) is effective onmany broadleaf weeds. Percentage use pattern notestablished on barley in eastern Washington. Po-tential for injury to barley is relatively great withthis product, therefore rate and application timingis restricted. Applications are generally 2 to 4 oz.product/A or 0.0625 lbs. a.i./A from emergence upto the four-leaf stage of the crop. Dicamba is typi-cally used in combination with other broadleafherbicides such as MCPA to increase the controlspectrum or as a potential herbicide-resistancemanagement tool.

Picloram (Tordon 22K) is effective on manybroadleaf weeds and may be applied from thethree-leaf until the jointing stage of the crop, but isused very little in Washington as it restricts rota-tion crop options. Tordon 22K is restricted to 1.5oz./A annually, but applications using 0.5 to 1.0oz. product or 0.023 lbs. a.i./A would be morelikely. It is most commonly used as a spot treat-ment on perennial weeds either pre- or post-har-vest.

Diuron (Karmex DF) is effective for grassand broadleaf control when applied preemergenceat 1.2 to 1.6 lbs. a.i./A. This photosynthetic dis-

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rupter may only be used on winter barley in west-ern Washington.

Metribuzin (Lexone, Sencor) is a photosyn-thetic disrupter used infrequently for broadleaf andgrassy weed control in Washington barley. Applica-tion would be limited 3 to 3.75 oz. a.i./A. May beapplied to barley from the two-leaf to jointingstage of growth. May injure certain varieties ofbarley.

Paraquat (Gramoxone Extra) is a nonselec-tive, restricted-use herbicide applied at about 0.5to 0.75 lbs. a.i./A as a preplant or preemergenceherbicide for control of weeds in no-tillage or re-duced tillage production systems. It is a photosyn-thetic disrupter.

Chlorsulfuron (Glean) is an amino-acid-synthesis inhibitor used infrequently for broadleafweed control on winter or spring barley. Glean islimited to 0.23 lbs. a.i./A, and Finesse, which ispremixed with metsulfuron, is applied at 0.15-0.3lbs. a.i./A . May be applied from the two-leafthrough the second-joint stage of barley growth.Due to potential for resistance development,growers apply chlorsulfuron in combination withbroadleaf herbicides with different modes ofaction. Persistance of chlorsulfuron in the soil,particularly with increasing pH, may restrict croprotation options, including rotating back to barley.

Metsulfuron (Ally) is an amino-acid-synthe-sis inhibitor effective primarily for broadleaf weedcontrol. Percentage use pattern not established inthe state. May be applied from the two-leafthrough the boot stage of barley growth. Due topotential for resistance development, growers applymetsulfuron in combination with broadleaf herbi-cides with different modes of action. Persistance ofmetsulfuron in the soil, particularly with increas-ing pH, may restrict crop rotation options. Ratesrange from 0.06 to 0.18 lbs. a.i./A. Sold as Finessewhen premixed with chlorsulfuron and Canvaswhen premixed with thifensulfuron.

Prosulfuron (Peak) Used at 0.22 to 0.29 lbs.a.i./A, this amino-acid-synthesis inhibitor is effec-

tive primarily for broadleaf weed control. Percent-age use pattern not established in the state. Maybe applied from the three-leaf through the second-joint stage of barley growth. Due to potential forresistance development, growers apply prosulfuronin combination with broadleaf herbicides withdifferent modes of action. Persistance ofprosulfuron in the soil, particularly with increasingpH, may restrict crop rotation options.

Triasulfuron (Amber) Used at standard ratesof 0.21 to 0.35 lbs. a.i./A, this amino-acid-synthe-sis inhibitor is effective primarily for broadleafweed control. Percentage use pattern not estab-lished in the state. May be applied when barley isin the two-leaf through the preboot stage ofgrowth. Due to potential for resistance develop-ment, growers apply triasulfuron in combinationwith broadleaf herbicides with different modes ofaction. Persistance of triasulfuron in the soil, par-ticularly with increasing pH, may restrict croprotation options, including rotating back to barley.

Glyphosate (Roundup Ultra) is a non-selec-tive systemic herbicide used at 0.375 to 0.5625 oz.a.i./A for control of annual and perennial weeds.An amino-acid-synthesis inhibitor, it may be usedas a preplant or preemergence herbicide for controlof weeds in no-tillage or reduced tillage productionsystems. Also may be used as a preharvest aid todesiccate weeds that could interfere with the har-vest operation or as a spot treatment for perennialweeds.

Diclofop (Hoelon) this restricted-use herbi-cide is used at 0.75 lbs. a.i./A for post-emergencecontrol of several species of annual grasses. Per-centage use pattern not established in the state.May be applied to barley at the one- to four-leafstage of growth. Resistant populations of weedsmay develop. Applying diclofop within five daysof the application of certain broadleaf herbicidesmay reduce grass control.

Difenzoquat (Avenge) Used at rates of 0.625to 1 lb. a.i./A. Post-emergence control of wild oat.Percentage use pattern not established in the state.May be applied to wild oat at the three- to five-leaf

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stage of growth. Some loss of barley yield may havealready occurred by waiting until weeds are in theproper stage for application. Resistant populationsof weeds may develop.

Imazamethabenz (Assert) Used at a rate of0.41-0.47 lbs. a.i./A. Post-emergence control ofwild oat. Percentage use pattern not established inthe state. May be applied to wild oat at the one-to four-leaf stage of growth. Subsequent emergenceof weeds may result in reinfestation. Resistantpopulations of weeds may develop. Soil persistancemay restrict crop rotation options.

Trifluralin (Treflan) Used at 0.5 to 0.75 lbs.a.i./A. Post-plant incorporation control of certainannual grass and broadleaf weeds in barley. Per-centage use pattern not established in the state.Required mechanical incorporation precludes usein no-tillage and direct seeding systems. Not effec-tive against wild oat.

Metam-Sodium (Vapam or Soil-Prep) is asoil fumigant sometimes used as a preplant treat-ment for crops in rotation with barley. Besidescontrolling weeds, it manages certain nematodesand diseases. With Washington barley being a lowor negative cash crop, no fumigation takes placesolely for barley (or for its primary rotation crop,wheat), but it might be used for a higher valuecrop in the rotation such as potato.

Diseases

STRIPE RUST

Puccinia striiformis hordei

Stripe rust is primarily a disease of cool cli-mates. It has caused widespread, devastating lossesin each region where it has occurred. Barley striperust, which was first detected in the United Statesin 1991, has become the most widely destructivedisease of barley in the West. It is known to re-duce yields by 30 to 100% and to reduce grainquality. Damage to barley depends on its stage ofgrowth relative to rust development. Rust devel-opment at an early stage of growth causes the mostdamage.

Controls

CulturalStripe rust can be controlled by resistant

cultivars; some newly released barley cultivars inthe West are resistant to stripe rust.

ChemicalSeed treatment with Baytan (Triadimenol)

at 1.5 oz. product/cwt. or 0.031 lbs. a.i./cwt canprotect barley seedlings from infections in theevent of early onset of disease, and thus delay dis-

ease development. Foliarapplication of Tilt(Propiconazole) or Folicur(Tebuconazole) at 4 fl. oz.product/A or 1.8 oz. a.i./Awill control stripe rust.Tilt is currently registeredfor use. Folicur has had anemergency exemptionfrom registration from1996 to 2000 (Section 18numbers for 1998 through2000 are 98-WA-18, 99-WA-16, and 00-WA-19).

Barley heavily infected with stripe rust. Photo courtesy of University of Oregon and Jay Pscheidt.

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BARLEY YELLOW DWARF (BYDV)

Barley yellow dwarf, caused by barley yellowdwarf virus (BYDV), is the most important andwidespread virus disease of barley in the world. InWashington, vectors that transmit BYDV includecorn leaf aphid, bird-cherry oat aphid, Englishgrain aphid, and, to a lesser extent, other aphidssuch as rose-grass aphid. Losses from barley yel-low dwarf can approach 100% when plants areinfected early. Losses of 40% are not uncommonin commercial fields and are usually highest withearly infections. Losses vary among cultivars, iso-lates of BYDV, and environmental conditions.Yield losses result from fewer heads per plant,fewer seeds per head, partial sterility, and reducedkernel size and weight.

Controls

CulturalAvoidance of early fall and late spring plant-

ing allows the plants to develop at a time whenaphid populations are lowest. Resistant or tolerantcultivars have potential for control. The aphidvectors have a wide variety of alternate hosts.Corn leaf aphid favors wild grasses, oat, millet,timothy, fescue, and, occasionally, corn, while thebird-cherry oat aphid favors almost any grass, in-cluding bluegrass lawn types as well as corn. Prox-imity to alternate hosts could enhance vectors’ability to spread barley yellow dwarf.

ChemicalUse of systemic insecticides such as Gaucho

(Imidacloprid) at 2 oz. product/cwt. or 0.0625 lbs.a.i./cwt. will prevent transmission of BYDV byaphids. Use of foliar insecticide Di-Syston (Disul-foton) will reduce aphid population and thereforereduce the spread of BYDV.

SCALD

Rhyncosporium secalis

Scald is a common disease of barley in cool,semi-humid growing regions. Yield losses as highas 35-40% have been reported. However, losses of1-10% are common.

Controls

CulturalBarley scald is reduced by destruction of the

sources of primary inoculum (infected seed orresidue). Some cultivars are resistant to scald.

ChemicalSeed treatment has not been established for

disease control. Foliar spray with Tilt at the rateof 4 fl. oz. product/A has been shown to controlthe disease.

NET BLOTCH

Pyrenophora teres

Net blotch is most important in areas ofhigh humidity and high rainfall. The severity of

Scald can be recognized by oval to elongate spots withlight centers and dark brown to black edges.

Photo courtesy of OSU Extension Plant Pathology.

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net blotch is also related to the susceptibility ofcultivars. There has been an increase in the inci-dence of net blotch in recent years, particularlybecause of growing continuous barley, minimumtillage, and irrigation. Yield losses can approach100% in severely affected fields of highly suscep-tible cultivars, but more typical losses range from10 to 40%.

Controls

Cultural/ChemicalDestruction of primary inoculum is the first

step for control of net blotch. Use of pathogen-free seed or seed treated with fungicides likeVitavax will prevent introduction of the pathogeninto clean fields. Rotation with non-susceptiblecrops for at least two growing seasons reduces netblotch. Resistant cultivars are an effective meansof control.

STEM RUST

Puccinia graminis

Like stripe rust and leaf rust, specializedstrains of stem rust fungus are adapted to specificcrops (wheat, rye, oats, and certain grasses). How-ever, the strains that infect barley may come from

wheat, rye, or other grasses. Damage to barleydepends on its stage of growth relative to rust de-velopment. Epidemics that occur before thedough stage of plant growth are most damaging.Losses caused by stem rust depend upon type ofresistance and/or conditions favorable for rust de-velopment. Warm and wet late spring conditionsare extremely favorable for stem rust development.

Controls

Cultural/ChemicalStem rust is best controlled by resistant cul-

tivars and application of foliar fungicides. Foliarapplication of Tilt or Folicur (4 fl. oz. product/Aor 1.8 oz. a.i./A) will control stem rust. Sprayshould be timed between boot to milk stage. Tiltwill control stem rust but cannot be used past flagleaf emergence.

LEAF RUST

Puccinia hordei

Leaf rust is important in some regions wherethe crop matures late. In Washington, it is more ofa problem west of the Cascade Mountains thaneast of the mountains. Damage to barley dependson the stage of growth relative to when rust beginsto develop. Severe early infection causes shriveledkernels and a decrease in grain number. Epidemicsthat occur before or during flowering are mostdamaging.

Controls

Cultural/ChemicalLeaf rust can be controlled through resis-

tance and cultivars that are slower to express rustand through foliar applications of systemic fungi-cides. Seed treatment with Baytan (Triadimenol)at 1.5 fl. oz. product/cwt. or 0.03 lbs. a.i./cwt. willcontrol early development of leaf rust on springbarley. Foliar application of Tilt (Propiconazole)or Folicur (Tebuconazole) at 4 fl. oz. product/A or

Net blotch symptoms: note the narrow, dark brownstripes extending across and down the leaf.

Photo courtesy of University of Oregon and Paul Koepsell.

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1.8 oz. a.i./A will control leaf rust. Because leafrust is not a big problem in most barley produc-tion areas in the State of Washington, there havebeen almost no fungicide applications that arespecifically for control of barley leaf rust.

BARE PATCH

Rhizoctonia spp.

Bare patch is a disease of barley in manyparts of the world. The disease is a problem inWashington State, but seldom causes serious losses.The disease has been associated with minimumtillage and planting too soon after use of herbicidesto kill previous cereal crops.

Controls

CulturalTillage to break the continuous crop is

highly effective in controlling the disease. Vigor-ous plants growing in well-fertilized soil are lesslikely to become severely diseased. Resistant culti-vars are not available.

ChemicalSeed treatment with PCNB at the rate of 3

fl. oz. product /cwt. or 0.05 lbs. a.i./cwt. may pro-vide some control. Chemical fallow or mechanicaltillage can significantly reduce the disease severity.

SEEDLING BLIGHT AND COMMON ROOT ROT

Fusarium culmorum, F. graminearum

Several fungi cause seedling blight and com-mon root rot or dryland root rot, but the two spe-cies listed above are the most common pathogensin the Pacific Northwest. These fungi can attackseedlings, foliage, heads, and grain. Losses fromcommon root rot are severe in years of below nor-mal soil moisture when plants are drought stressed.

Controls

CulturalUsing clean seed may reduce seedling infec-

tion. Planting in cool soil can reduce seedlinginfection. Root rot is usually less severe on barleythat has been optimally fertilized. Over-fertiliza-tion, especially with nitrogen, can make root rotmore severe by promoting excessive use of water.Using resistant or tolerant cultivars may reducecommon root rot.

ChemicalSeed treatment with broad-spectrum fungi-

cides can control seedborne infections. Imazalilused as seed treatment at. 0.25 to 0.5 fl. oz. prod-uct/cwt. may reduce Fusarium root rot (drylandroot rot), but it has seldom been used in Washing-ton for this purpose.

POWDERY MILDEW

Erysiphe graminis hordei

Powdery mildew is most damaging in highhumidity climates. Powdery mildew of barley isrestricted to wild and cultivated barley and doesnot attack other cereals. Yield losses are greatestwhen plants are infected as seedlings and diseasedevelopment continue through flowering.

Controls

CulturalResistant cultivars are effective until the

virulent races of the fungus become prevalent,which usually occurs about three to four years afterthe release of the resistant cultivars. The pathogenthrives on lush, nitrogen-rich plants and is lessdamaging when correct proportions of nitrogen,potassium, and phosphorus are used.

ChemicalFoliar application of Tilt or Folicur at 4 fl.

oz. product/A or 1.8 oz. a.i./A will control pow-

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dery mildew. In the Northwest, spraying for con-trol of powdery mildew is usually not necessarybecause it seldom causes severe yield losses in thisregion, but if the fungicides are used for rust con-trol, they will also control powdery mildew.

COVERED SMUT

Ustilago hordei

Covered smut occurs in the state of Wash-ington, but losses from the disease are rare becausethe environments are not conducive and majorbarley production areas do not have a history ofthe disease. In addition, seed treatments have re-duced incidence of the disease. However, becauseheads infected with covered smut are harvestedwith healthy grain, losses can arise from loweredgrade due to smutty grain.

Controls

Cultural/ChemicalCovered smut is controlled effectively in

Washington State by using seeds treated withBaytan at 0.75-1.5 fl. oz. product/cwt.;Vitavax atthe rate of 9-12 fl. oz. product/cwt.; or DividendXL at 1-2 fl. oz. product/cwt. Resistant cultivarswould likely work, but because of the success ofseed treatment, little effort has been placed ondeveloping resistant cultivars.

LOOSE SMUT

Ustilago nuda

Loose smut is most common in areas of highhumidity and rainfall at anthesis (open-flowerperiod). In most regions, losses from loose smutare minor. Occasionally, highly susceptible culti-vars sustain some loss. Quality of harvested grainis not affected, because the smut spores are dis-persed long before harvest. In Washington State,the disease is generally not a problem because ofunfavorable weather conditions. Infection occursonly during flowering and is favored by wet andcloudy weather and moderate temperatures.

Controls

CulturalResistant cultivars control loose smut, but

resistance to loose smut is not a priority in barleybreeding programs in Washington State becausethe disease is not economically important.

Chemical Seed treated with Vitavax or Baytan at the

rate of 9-12 fl. oz. product/cwt. or Dividend XL at1-2 fl. oz. product/cwt. will control loose smut.

BLACK CHAFF AND BACTERIAL LEAF STREAK

Xanthomonas translucens pv. translucens

These diseases almost disappeared duringthe use of organic mercury seed treatments. Withelimination of the organic mercury seed treat-ments, the diseases have again become wide-spread, especially where sprinkler irrigation is used.Yield losses can be 10-15%. The diseases maypersist from one season to the next on barley seed,barley straw, winter barley, or grass hosts. It doesnot survive in soil for very long. The fungus can

Covered smut symptoms.Photo courtesy of OSU Extension Plant Pathology.

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spread from plant to plant by wind and rain, in-sects, or mechanical contact. The seed may be-come infected when heads are infected, but effec-tive transmission to seedlings is usually 5% or less.Major spread occurs under sprinkler irrigation.

Controls

CulturalUse of pathogen-free seed produced under

dry conditions, coupled with crop rotation to de-stroy infested plant debris, is the best control mea-sure. No resistant cultivars are known.

ChemicalSeed treatments containing copper reduce

seedborne inoculum but do not prevent spreadfrom infested plant debris.

SNOW MOLDS

Fusarium and Typhula spp.

Snow molds are diseases of the plant tissuenear the soil surface under the snow. Snow coverprovides an insulating blanket that keeps soil tem-perature near 0ºC even though air temperaturesmay be much lower. Beneath deep snow, barleyplants slowly deplete their carbohydrate and thentheir protein reserves. In this weakened state, theyare predisposed to snow mold. Since this is a po-tential problem only for winter barley, which rep-resents a very small portion of Washington barley,and since winters severe enough to cause snowmold (deep, long-standing snow) would produceconditions too risky for winter barley anyway,snow mold is not a concern at this time in Wash-ington.

Controls

CulturalGrowers avoid planting in areas of long,

persistent snow cover. No barley cultivars areknown to have high resistance to snow mold.

ChemicalBaytan (Triadimenol) used as seed treatment

at the rate of 9-12 fl. oz. per 100 lbs. will controlspeckled snow mold caused by Typhula spp.

PYTHIUM ROOT ROT

Pythium spp.

Phythium root rot is most common wheresoils remain wet for long periods.

Pythium species can attack a broad range ofhosts, including barley. Pythium root rot is associ-ated with direct-seeded (no-till) barley in the Pa-cific Northwest.

Controls

CulturalThe standard management practices includ-

ing tillage used by most barley producers are effec-tive for preventing Pythium root rot. Draininglow spots to prevent excessive soil moisture reducesthe disease.

ChemicalApron (mefenoxam) is used as a seed treat-

ment at a rate of 0.32 to 0.64 fl. oz. product/cwt.

SCAB (HEAD BLIGHT)Fusarium spp.

Scab on barley, also called Fusarium headblight, is caused by the same Fusarium spp. thatcause scab on wheat and other small grains andcause stalk rot on corn. It can also cause seedlingblight and root rot. Since 1993, the disease hasbeen very destructive in many regions where barleyis grown in rotation with corn and in acreage withreduced tillage. Scab has not been a big concernhistorically in Washington because the weatherconditions and cropping systems are generally

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unfavorable for scab development. Absence ofheavy rain at heading to anthesis and post-anthesisand dry late-spring conditions are not conducivefor scab development. Scab causes losses by reduc-ing yield and quality and by producing toxins thataffect animals and humans. The toxins also affectthe taste qualities of beer.

Controls

CulturalCrop rotation with at least a one-year break

in cereal and grass cultivation is practiced for con-trol of scab. Barley is generally not planted follow-ing corn, or crop residues of corn (particularlyirrigated corn) may be plowed under. Becausespores of the scab fungus can be airborne for somedistance, barley growing is also avoided near fieldswith abundant corn residue. In irrigated barley,growers reduce irrigation during heading to matu-rity to reduce scab. Resistant cultivars are beingdeveloped for regions where scab is an importantdisease of barley.

ChemicalTreatment of seed with an effective fungicide

like Imazalil and Dividend XL (mefenoxam anddifenoconazole) may protect seedlings fromseedborne inoculum. Dividend XL (24c, WA-990014) is used at a rate of 2 fl. oz. product/cwt.on spring barley only. Foliar fungicides like Folicurhave potential for reducing head blight.

SPOT BLOTCH

Cochliobolus sativus

Spot blotch causes losses only in regionswith a warm, humid climate and is rarely a prob-lem in barley grown under semiarid conditions.The severity of spot blotch varies greatly from yearto year. Spot blotch has reduced yields by 36% inhighly susceptible cultivars. In Washington State,it is a minor disease.

Controls

CulturalThe use of pathogen-free or fungicide-

treated seed is suggested for control of the disease.Rotation with non-susceptible crops aids in thedestruction of infested residue, which reduces thelevel of primary inoculum. However, soilborneinoculum may negate the value of residue destruc-tion. Cultivars with an acceptable level of resis-tance to spot blotch have not been developed.

ChemicalFoliar applications of fungicides, such as Tilt

at 4 fl. oz. product/A or 1.8 oz. a.i./A will controlspot blotch.

Spot blotch symptoms: dark, circular brown spotsforming blotches over large areas of the leaf.

Photo courtesy of University of Oregon and Paul Koepsell.

Insects

At least thirty insect species attack, or havethe potential to attack, barley grown in Washing-ton. Most are considered insignificant or minorpests. Their importance is often local and may varydepending upon season and other conditions. Themost commonly encountered pests include cerealaphids, grasshoppers, wireworms, cutworms andarmyworms, and Hessian fly. A pest new to Wash-ington wheat, the cereal leaf beetle, has the poten-tial to be a pest for Washington barley.

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Because of the low economic return on bar-ley, chemicals are not used extensively for insectcontrol. Simple economics precludes many grow-ers’ use of seed or foliar treatments. Insecticideapplications are often limited to outbreak condi-tions or in response to threats of insect-vectoreddiseases like barley yellow dwarf virus (see Diseasesection). New, cost-effective pest control optionsare needed for barley.

No statistics on chemical use in barley areavailable in Washington. Insecticides used in barleyproduction can be grouped into three categories:1) pre-planting; 2) pre-emergence; and 3) post-emergence materials. Pre-planting chemicals in-volve seed treatments prior to planting (e.g.,imidacloprid, lindane). Pre-emergence chemicalsare primarily soil treatment substances injected orapplied at time of planting (e.g., disulfoton). Post-emergence chemicals are used as foliar sprays ap-plied after the plants have emerged; these includedisulfoton, and malathion. Although barley andwheat share many insect pests and diseases, thechemicals used to control these insects may differ.For example, compounds recommended for use onwheat such as Lorsban, Phorate, Thimet, andDimethoate are not registered on barley.

Washington entomologists are working withbarley growers and the Washington Barley Com-mission to develop and institute stable, long-last-ing biological control programs for barley.

CEREAL APHID

Various spp. includingCorn Leaf Aphid, Rhopalosiphum maidis (Fitch);

Bird Cherry-Oat Aphid,Rhopalosiphum padi (Linnaeus);

English Grain Aphid, Sitobion avenae (Fabricius);Rose-Grass Aphid,

Metopolophium dirhodum (Walker);Russian Wheat Aphid, Diuraphis noxia

Aphids are the most important insect pestsof barley in Washington. Occasionally, aphids aresufficiently abundant to cause localized direct

damage by feeding on the plants, generating toxinsthat stunt or deform the barley, but for the mostpart they are a concern in barley for the indirectdamage they bring about by vectoring barley yel-low dwarf virus (BYDV, see Disease section). Rus-sian wheat aphid is not known to vector BYDV,but is a potential direct pest of barley in Washing-ton.

Aphids may occur in colonies of 300 to500+ individuals. Colonies develop in protectedareas near the bases of leaves, in leaf whorls, or onstems inside leaf bases. Some occur within tightlyrolled leaves or in trapped seed heads caused bytoxic secretions produced during feeding. Cerealaphids often occur in mixed colonies of differentspecies. They are often held in check by naturalenemies.

Aphids are cyclic pests and can becomeproblematic when conditions favor overwinteringsurvival or rapid buildup during spring. Whenwinters are warm, aphids overwinter on grasses andfall-seeded small grains, then re-invade fields fromadjacent or distant overwintering sites insouthcentral Washington during the spring.Aphids reproduce quickly and populations canincrease dramatically once colonies are established,if environmental constraints are limited. Earlydetection is difficult as aphids occur initially in lownumbers and hide in protected areas on plants.Late-planted barley is especially susceptible toaphid attack. Under normal conditions, plants canusually withstand late season infestations and pro-duce seed without significant reductions.

Controls

CulturalThe timing of barley planting does a great

deal to discourage aphids’ developing to problemlevels. The majority of Washington barley is springbarley; that which is planted relatively early (Feb-ruary through April) is less at-risk for aphid infes-tation. Barley planted in May, especially mid- tolate-May, is at great risk for aphid infestation.(Such late plantings tend to perform poorly agro-nomically anyway.) The barley planted earlier inthe spring tends to be well enough established to

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withstand the impacts of the later arrival and de-velopment of the aphid populations.

Winter barley comprises a very small part ofWashington’s barley crop; it would be much moresusceptible to BYDV and timing the plantings forlate in the season might help diminish the impactof aphids.

Plants that harbor non-economic aphidsmay serve as hosts for natural enemies or providenectar and pollen resources for predatorybeneficials. When located adjacent to croppingsystems, a diversity of plant types may offer refugeand/or food for overwintering agents. Tillagemethods that leave undisturbed marginal stripsalong fence rows and at field edges may also en-hance conservation of overwintering sites for natu-ral enemies.

BiologicalCereal aphids are attacked and usually

checked by an array of natural and introducedenemies. Most of these agents are established in thefield, but there is a need in some cases (e.g. birdcherry-oat aphid) to strengthen and enhance thepool of natural enemies. Among beneficial preda-tors found in eastern Washington are parasitoidwasps, predatory ladybird beetles, lacewings, andaphid-attacking flies. Selected pathogenic fungiare also known to control aphid populations.Many of these natural enemies are adapted to enterrolled leaves or confined areas to attack aphids inall life stages. Several of the natural enemies re-spond quickly to match increasing aphid numbers.This is an interactive complex of enemies that hasbeen responsible for maintaining most cerealaphids in low numbers and reducing the impact ofthe Russian wheat aphid (RWA) since its arrival inthe Pacific Northwest in 1989.

ChemicalPost-emergence insecticide treatments to

control aphids may become necessary when post-emergence infestation levels average 10% per tiller,stem, or head. Some scouting is practiced to deter-mine actionable levels.

Disulfoton (Di-Syston 8E) is recommendedfor use as either a soil treatment at 1 lb. a.i./A or apost-emergence foliar spray at 0.5 to 1 lb. a.i./A forcontrol of Russian wheat aphid. It has a 30-daypre-harvest restriction. Russian wheat aphid hasnot caused problems in Washington in more thanfour years due to the success of biocontrol. Iftrends hold, chemical pest management will sel-dom be needed.

Methyl Parathion (Penncap-M at 0.25 to0.75 lb. a.i./A) is a foliar spray for use against Rus-sian wheat aphid and is effective against aphids ingeneral.

Malathion (Malathion at 1 lb. a.i./A) isanother post-emergence foliar spray. It has notproven very effective at aphid control, but worksagainst grasshopper.

Methomyl (Lannate at 0.23 to 0.45 lb. a.i./A) is a foliar spray.

Endosulfan (Thiodan 3EC at 0.5 lb. a.i./A)is a foliar spray.

Carbofuran (Furadan 4F at 0.125 to 0.25lb. a.i./A) is a foliar spray used for grasshoppers onbarley which also seems to be effective againstaphids, but would be cost-prohibitive to use forthe chief purpose of aphid protection.

GRASSHOPPERS

various spp.

Adults and nymphs of several species are notusually considered pests unless their populationsreach outbreak numbers. High populations incertain years can be devastating to all availableforage, including heads, stems and foliage of bar-ley. Typically residents of non-crop, rangelandareas, grasshoppers will move into adjacent crops,including cereal grains.

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Controls

BiologicalThe microsporidian protozoan Nosema

locustae, labeled for use on croplands, is a slow-acting pathogen effective when used as a grasshop-per bait around areas of infestation. Label suggestsno less than 1 lb. product/A per application.

Chemical

Disulfoton (Di-Syston 15G at 1 lb. a.i./A,24c WA-850036) is a granular systemic registeredfor use in Washington against aphids, grasshop-pers, and Hessian fly. It is used at planting timeand has a 30-day preharvest restriction. There arereports of phytotoxic activity on barley with thiscompound. Limited to one application per season.

Malathion at 1 lb. a.i./A is a post-emergencefoliar spray effective against grasshoppers.

Carbofuran (Furadan 4F at 0.125-0.25 lb.a.i./A) is applied as a foliar spray prior to heading.This compound is limited to two applications peryear.

WIREWORMS

various spp.

These minor barley pests have multiple-yearlife cycles. Sporadic, localized outbreaks can causeeconomic damage. Damage occurs when larvaeburrow into kernels and leaf whorls above seed(fall-planted) or kernels and underground parts ofplants after sprouting (spring-sown). Damage ismost severe during cool, wet spring weather.

Controls

CulturalWireworms may not be a problem if land is

treated with a soil fumigant or chemicals beforegrains are planted. Soil fumigants are not likely tobe used for barley alone because of cost.

Chemical

Imidacloprid (Gaucho 480 at 3 fl. oz. prod-uct/100 lbs. seed) is used as pre-planting seedtreatment. It has a 45-day pre-harvest restriction.

Lindane (Lindane at 0.135 fl. oz. product /100 lbs. seed) is another seed treatment. Certifiedseed may be already treated with this material. It ismoderately effective against low populations ofwireworms.

Telone II or C17 can be used as pre-plant-ing soil fumigant, but is not cost-effective to usesolely for reducing wireworm in barley.

CUTWORMS AND ARMYWORMS

various spp. includingVariegated Cutworm, Peridroma saucia;

Armyworm, Podoptera frugiperdaor Pseudaletia unipuncta;

Bertha Armyworm, Mamestra configurata; andZebra Caterpillar, Ceramica picta

These and other species of larval moths areconsidered minor pests that may damage youngbarley plants early in spring. Caterpillar forms livein the soil or near the base of plants.

ControlsCertain controls are available for cutworms

and armyworms, but are rarely used due to costand margins.

Chemical

Endosulfan (Thiodan 3EC at 0.5 lb. a.i./A)is a foliar spray that can be applied before headsform. Not widely used.

Methomyl (Lannate at 0.23-0.45 lb. a.i./A)is a foliar spray registered on armyworms but notcutworms. Works best when applied when wormsare smaller and younger.

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HESSIAN FLY

Mayetiola destructor

Traditionally a pest on wheat, Hessian flyhas caused some damage in southeastern Washing-ton barley, notably in Asotin, Garfield, and Co-lumbia counties. Larvae feed at or near the plantcrown, or at the leaf bases. There are two to threegenerations per year. Feeding damage stuntsplants, kills upper portions, and reduces yield.Stems are weakened and tillers break off at harvest.

Controls

CulturalTillage helps control Hessian fly. It is more

of a problem in direct-seeded (“no-till”) situations.Studies suggest that certain varieties, includingBaronesse, may be resistant to Hessian fly. Breed-ing programs are underway to develop greater re-sistance.

BiologicalAt least six species of parasitoid wasps attack

Hessian fly. Unfortunately, these parasites destroylater developmental stages, which comes too late inthe life cycle to affect the damaging larval popula-tion.

Chemical

Imidacloprid (Gaucho 480 at 1-3 fl. oz.product/100 lb. seed) is a seed treatment effectiveagainst first generation fly, and possibly some sec-ond generation. Also used as an aphid control.

Disulfoton (Di-Syston 15G at 1 lb. a.i./A,24c WA-850036) is a granular systemic registeredfor use in Washington for grasshoppers, and Hes-sian fly. It is used at planting time and has a 30-day pre-harvest restriction. There are reports ofphytotoxic activity on barley with this compound.Limited to one application per season.

CEREAL LEAF BEETLE

Oulema melanopus

This pest has recently been seen on wheat inthe Spokane area. While it is not yet a pest toWashington barley, it has the potential to becomeone. Carbofuran is proven to be effective againstcereal leaf beetle; lambda-cyhalothrin should alsobe effective but at present is not registered for useon barley. Based on other states’ experience,biocontrol (both disease- and insect-based) holdspromise in managing this pest.

Pest Control Issues

Additional, cost-effective chemical controlsare needed in barley, especially for wireworms.

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AuthorsDr. William J. TurnerWashington State UniversityP.O. Box 646420Pullman, WA 99164-6420Phone (509) 335-3720Fax (509) 335-1009E-mail turnerwj@wsu.edu

Dr. Joseph YenishWashington State UniversityP.O. Box 646420Pullman, WA 99164-6420Phone (509) 335-2961Fax (509) 335-1758E-mail yenish@wsu.edu

Dr. Roland F. Line, emeritusWashington State UniversityP.O. Box 646430Pullman, WA 99164-6430Phone (509) 335-3755FAX (509) 335-7674E-mail rline@wsu.edu

Dr. Xianming ChenUSDA-ARS/Washington State UniversityP.O. Box 646430Pullman, WA 99164-6430Phone (509) 335-8086FAX (509) 335-9581E-mail xianming@mail.wsu.edu

Technical and Industry ContactsExtension Weed ScientistDr. Joseph YenishWashington State UniversityP.O. Box 646420Pullman, WA 99164-6420Phone (509) 335-2961Fax (509) 335-1758E-mail yenish@wsu.edu

EntomologistDr. Keith S. PikeWashington State UniversityIrrigated Agriculture Research

and Extension Center24106 N. Bunn RoadProsser, WA 99350-9687Phone (509) 786-9269Fax (509) 786-9370E-mail kpike@tricity.wsu.edu

Plant PathologistDr. Timothy MurrayWashington State UniversityP.O. Box 646420Pullman, WA 99164-6430Phone (509) 335-9541Fax (509) 335-9581E-mail: tim_murray@wsu.edu

AgronomistDr. Steven E. UllrichWashington State UniversityP.O. Box 646420Pullman, WA 99164-6430Phone (509) 335-4936Fax (509) 335-8674E-mail ullrich@wsu.edu

IndustryMary Palmer-Sullivan, AdministratorWashington Barley Commission905 W. Riverside Suite 501Spokane, Washington 99201Phone (509) 456-4400Fax (509) 456-2807Email mpsulli@foxinternet.comURL www.washingtonbarley.org

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References

(1) 1999 Washington Agricultural Statistics. Washington Agricultural Statistics Service.

(2) 1996 Crop Year Marketing Survey Results, in 1998-1999 Washington Barley Resource Guide.Washington Barley Commission.

(3) Willett, G. S., and A. T. Jessup. 1997. An Economic Analysis of Alternative Crop Rotations inthe Intermediate Rainfall Area of Eastern Washington: The Wilke Farm Experience. WashingtonState University College of Agriculture and Home Economics, Cooperative Extension. Availableon-line at http://farm.mngt.wsu.edu/EB1869.pdf.

(4) Washington Barley Commission website, http://www.washingtonbarley.org.

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College of Agriculture and Home Economics

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Copyright 2001 Washington State University

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Issued by Washington State University Cooperative Extension and the U.S. Department of Agriculturein furtherance of the Acts of May 8 and June 30, 1914. Cooperative Extension programs and policies areconsistent with federal and state laws and regulations on nondiscrimination regarding race, sex, religion,age, color, creed, national or ethnic origin; physical, mental or sensory disability; marital status, sexualorientation, and status as a Vietnam-era or disabled veteran. Evidence of noncompliance may be re-ported through your local Cooperative Extension office. Trade names have been used to simplify infor-mation; no endorsement is intended. Published April 2001. (Publication number MISC0367E.)