Conard, Susan G.

Emmingham, William H.

Oregon State University. Forest Research Laboratory

Undetermined

ScholarsArchive@OSU

AOflOfl3O43OI77SPECIAL PUBLICATION 7 JANUARY 1984HERBICIDES FOR GRASS ANDHERBACEDUS WEED CONTROL INOREGON AND WASHINGTONCURHEO/F76/2SUSAN G. CONAIRDW. H. EMMINGHAMFIGURE 1.AREAS (DIAGONAL LINES) DISCUSSED IN THIS PUBLICATION. SHADED AREAS INDICATEMOUNTAI NS.FOREJI REIEARCH LABORATORYOREGON STATE UNIVERSITY, COLLEGE OF FORESTRYCORVALLIS. OR 97331-5704 503-753-9166INTRODUCTIONThe purpose of this publication is to providea supplement to existing information on theeffects of herbicides used in forest vegeta-tion management on grasses and herbaceousweeds common in Oregon and Washington. It isintended to assist foresters in selectingappropriate herbicides. A glossary of termsused in the publication is included.This is one of a series of five publicationsconcerned with efficacy and selectivity ofmajor forestry herbicides in the PacificNorthwest. The other four publications dealwith: (1) brush and fern control on forestsites in western Oregon and Washington,(2) forest brush control in southwesternOregon, (3) shrub control in northeasternOregon and northern Idaho, and (4) clump andstem treatments for weed trees and shrubs inOregon and Washington. The five publicationscompile operational and experimental obser-vations obtained from researchers andforesters who use herbicides. Some responsesreported are based on only a small number ofobservations; therefore, injury ratings maybe revised as more information becomesavailable.GEOGRAPHIC AREA AND VEGETATION COMPLEXESThe herbicide treatments covered in thispublication are appropriate for aerial orground application on forest sites in Oregonand Washington (Fig. 1). Three of the mostimportant competitive herbaceous-vegetationcomplexes that commonly invade cutover areaswithin this region are listed below. Thesecomplexes are characterized by species thatfrequently become dominant on forest sitesfollowing silvicultural disturbance. 1Himalayan blackberry/grass complex.Major associated species include poisonoak, annual and perennial grasses,evergreen and trailing blackberry, andherbs and forbs common in the WillametteValley of Oregon. This complex occursin and around the Willamette Valley.1Common names follow Franklin and Dyrness (1973), pp.352-376, with the exceptions of evergreen blackberry (Rubuslaciniaus) wid Himalayan blackberry (Ruhus procerus).USING THIS GUIDEThere are many possible combinations of her-bicides, carriers, rates, and adjuvants thatmight be effective in particular situations.This publication does not attempt to provideinformation on every possible combination, orto provide detailed information on applica-tion techniques. Addition of drift-controlThe most common crop conifers in thisarea are Douglas-fir, western hemlockand western redcedar.2. Complexes dominated by beargrass andsedge. Major associated species includehuckleberry species and Pacific rhodo-dendron. This complex is found at upperelevations (2,500-5,500 ft) of theCascade Mountains. Commonspecies in this area are western whitepine, noble fir, Shasta red fir andPacific silver fir.3. A pinegrass/elk sedge complex. Majorassociated species include huckleberryspecies. This complex is found on theupper slopes of the Blue and RockyMountains. Common conifer crop speciesin this area are ponderosa pine, grandfir, lodgepole pine and Engelmannspruce.agents or surfactants, or application of chem-icals with nozzles outside the standard 350-to 400-micron mean droplet-diameter range cansubstantially affect results. For additionaldiscussion on the influence of applicationmethods, adjuvants, carriers, and other fac-tors on herbicide effectiveness, refer toCopies of this publication are available from the Forest Research Laboratory,ISOregon State University, Corvallis, Oregon, 97331. Support for the compilationand publication of this information was provided in part by CRAFTS (CoordinatedResearch on Alternative Forestry Treatments and Systems) and the OSU ExtensionService.Newton and Knight (1981) and Bohmont(1981).Susceptibility of target species and coniferseedlings to specific chemical treatments mayvary from one location to another. In addi-tion, efficacy and selectivity of herbicidetreatments are dependent on the phenology ofboth shrub and conifer. Therefore, propertiming of applications is crucial to success.Because weather patterns vary from year toyear, the date when plants are at the properphenological stage for a particular herbicidetreatment may change by several weeks fromone year to the next. Thus, the informationthat follows includes, whenever possible,phenological indicators that aid in achievingproper timing. Local pesticide representa-tives and forest extension agents may be ableto provide additional information to helpindividual operators determine appropriatetreatments for particular situations.We recommend strongly that operatorsestablish a system to survey sites prior totreatment and to maintain accurate records ofapplication dates, phenological condition ofshrubs and conifers at the time of spraying,weather (temperature, wind speed, humidity),herbicide rates, carrier volumes, anddetailed descriptions of application methods(nozzles, pressure, etc.). Such surveys andrecords can provide an important informationsource for improving local herbicideprescriptions in the future. The HerbicideEffectiveness Report in this publicationshows the types of information that should becollected.HERBICIDE TREATMENTS AND SPECIES RESPONSESFigure 2 shows typical responses of grasses,herbs and forbs, several blackberry species,and some of the major crop conifers toseveral herbicides and herbicide combi-nations. This figure can be used as a guidein determining an appropriate treatment basedon the target species present and on theimportance of protecting crop conifers, ifpresent.The guidelines below provide detaileddescriptions of the herbicide spray mixturesand comments on registration status, timing,rates, efficacy, and selectivity of treat-ments shown in Figure 2. Rates are foraerial application unless otherwise noted.Aerial application produces less effect forthe same rate than does evenly applied groundapplication; therefore, rates may be reduced10-20 percent for ground treatments in uni-form terrain. Even lower rates may beappropriate for ultra low volume (ULV)GUIDELINES1-3 SPRAY MIXTURE: Atrazine(Aatrex®). 14-5 lb/A (a.i.) withwater, or with water and 1 qtMoract® surfactant, to make10 gal/A (A acre). Groundapplications were 14 lb/A (a.i.) inwater to make 200 gal/A.applications (<.5 gallons of spray mixtureper acre).Products are listed by Weed Science Societyof America common names; trade names ofrepresentative products registered forforestry use are shown in parentheses (a.i. =active ingredient, a.e. = acid equivalent.)Operators should note that a given herbicidemay be available under various trade names,in various concentrations, and from variousmanufacturers.A U.S. Environmental Protection Agency (EPA)ruling allows the use of mixtures of her-bicide as long as individual components ofthe mix are registered and the combination isnot specifically forbidden by the individualproduct labels. Tank mixtures of some chemi-cals can increase the number of weed andgrass species controlled.REGISTRATION STATUS: Reg-istered for conifer release.COMMENTS: Fall and WinterTreatments Fall or winter appli-cations are most appropriate forareas of low rainfall (e.g.,3HRICIPE ANCAlER/AViTWL:1.2.3.478.9.10.11.12.13.1415.i4iiuw:.IU______guuggguuNJUY90 -100% (VeR( SEVERE)o-9o% (saVEa)l5-o % (MoPE.RTE)<Z5%(ucwf)NO VIE'I1-E INJLJR''INSUFF]CIENf OP1ASEASONSW IN1ER (cORNW.n)5': SFRINS (LPTE GXJRMANT 10 ENY5 5UMMEP (FOuAF-AC1rJE cRom)t.5; LAtE SL.1MMR (AF1R CONIFER &I) SEI)E FALL (SEp1EMSER OCIOSER)FIGURE 2.* N1O51 PATh IN 1HE6 cZDWMNS REB5ED ct'4 HI(H VOLUME UNDAI'PU CAT OMS3CARRIE.R5 AND ADDITIVESQ: OIL CARRIERW: WAlER C,\RRIERM M0ACX® ADDEDCOMfr\EN-iS -V:VARIALE INJUR'(EFFECTS OF HERBICIDES ON GRASSES, FORBS/HERBS AND ASSOCIATED TARGETSPECIES, AND ON CROP CONIFER SPECIES THAT OCCUR ON FOREST SITES INOREGON AND WASHINGTON.southwestern Oregon and east ofCascades) where spring rains maynot be adequate for activation.Fall applications apparently donot control orchard grass andsmooth brome as well as theycontrol other grass species.Spring Treatments Spring appli-cations may be more effective thanshown on most introduced andnative perennial grass species inthe pinegrass/elk sedge complex.However, atrazine causes little orno injury to pinegrass and elksedge. Addition of surfactantdoes not measurably increase effi-cacy. Spring applications aremost effective on grass species.4Volume of water carrier used toapply atrazine and simazine is notcritical. Atrazine is less effec-tive in soils that are high inorganic matter. Atrazine islikely to injure plug seedlings;allow 1 year after planting plugsbefore using atrazine.4 SPRAY MIXTURE: Atrazine(Aatrex®) and simazine (Princep®).2 lb/A (a.i.) + 2 lb/A (a.i.) inwater to make 10 gal/A.REGISTRATION STATUS: Reg-istered for conifer release.COMMENTS: See comments onatrazine (1-3) and simazine (5).5 SPRAY MIXTURE: Simazine(Princep®). L lb/A (a.i.) inwater to make 10 gal/A.REGISTRATION STATUS: Reg-istered for release.COMMENTS: Simazine is lesssoluble than atrazine and there-fore requires more rainfall toleach into the soil to a depthadequate for effective weedcontrol. As with atrazine, effec-tiveness is decreased by highlevels of soil organic matter.May injure plug seedlings; seeprecautions in comments on atra-zine (3).7 SPRAYMIXTURE: Dalapon (Dow-pon® M). 8 lb/A (a.i.) in waterto make 10 gal/A. Ground applica-tions were 8 lb/A (a.i.) in waterto make 200 gal/A.REGISTRATION STATUS: SpecialLocal Needs (SLN) registration forconifer site preparation inOregon, Washington, Idaho andCalifornia.COMMENTS: More likelytodamageconifers than are atrazine/dalaponmixtures. Efficacy reported onperennial grasses ranged fromintermediate to nearly completecontrol.8 SPRAY MIXTURE: Hexazinone(Velpar®, Velpar® L). 2 lb/A(a.i.) in water to make 15-20gal/A. Ground applications were2 lb/A (a.i.) in water to make200 gal/A.B SPRAY MIXTURE: Atrazine(Aatrex®) plus dalapon (Dowpon®M). 3-5 lb/A (a.i.) of each che- 9-12mical in water to make 10 gal/A.REGISTRATION STATUS: Reg-istered for conifer release.COMMENTS: This mixture willcontrol a greater number of peren-nial grass species than will atra-zine alone. Control of annualgrass species has ranged fromintermediate to nearly completecontrol. Light injury to pine athigher rates (i.e., nearing 5lb/A). See comments on atrazine(1-3).REGISTRATION STATUS: SLNregistration for use onreforestation areas and Christmastrees in Washington and Oregon.COMMENTS: Best results ifapplied in low-rainfall areas.Too much rain after applicationmay decrease effectiveness ontarget species and injure coni-fers. Appropriate rate is also afunction of soil type. Not recom-mended for use over smalltransplant stock.SPRAY MIXTURE: Glyphosate(Round-up®). 1.5 lb/A (a.i.) inwater to make 10 gal/A. Groundapplications were 2 lb/A(a.i.) in water to make 200gal/A.REGISTRATION STATUS: Reg-istered for conifer release andsite preparation.COMMETS: Higher ratesappropriate either for site pre-paration or for release east ofthe Cascade crest. Efficacy onannual grasses and forbs isexcellent when plants are green,5poor if they are senescent.Efficacy on trailing blackberryand poison oak probably higher inJune, July and early August thanin later months. Efficacy onHimalayan blackberry greatestduringAugust-October. Blackberryspecies must have green leaveswhen they are sprayed. Control onelk sedge before it has grown atleast 4 in. is poor, very goodafter 6-8 in. of growth. Springtreatment will injure conifers ifbuds have started to expand. Nosignificant soil residual act-ivity.13 SPRAY MIXTURE: 2,4-D low vola-tile ester (Weedone®, Esteron®).2 lb/A (a.e.) in water or dieselto make 10 gal/A.REGISTRATION STATUS: Reg-istered for release and site pre-paration.GLDSSARYADJUVANT: Any substance added inrelatively small quantity to a spraymixture for increased effectiveness ordrift control.BUD HARDENING: After fall bud hasbeen formed and is dark brown. Needlesfully expanded and hardened (fall).BUD SET: Formation of final restingbud on conifers (late summer to earlyfall).CARRIER: A substance used in rela-tively large amounts to dilute an her-bicide product for ease of applicationor increased effectiveness.DORMANT: The period in late winterbefore buds have broken on shrubs.DRIFT CONTROL: Any application meth-odology that reduces herbicide drift.Includes use of certain adjuvants,nozzle types or configurations.EARLY FOLIAR: Leaves not yet fullyexpanded on shrubs (spring).COMMENTS: Frequently applied incombination with any one of anumber of grass-control chemicalsto increase control of forbs.SPRAY MIXTURE: Pronamide(Kerb®). 2 lb/A(a.i.) in water tomake 10 gal/A.REGISTRATION STATUS: Is arestricted use pesticide.Registered for use on Christmastree plantations.SPRAY MIXTURE: Amitrole(Amitrol®-T). 2 lb/A (a.i.) inwater to make 10 gal/A.REGISTRATION STATUS: SLNregistration for site preparationand Douglas-fir release in Oregonand Washington.EFFICACY (effectiveness): The degreeto which a pesticide controls targetplant species.INJURY: The amount of reduction inlive canopy or foliage as compared tountreated plants of the same species.LATE FOLIAR: More than two-thirds ofleaves on shrubs fully expanded.PHENOLOGY: The stage of seasonalgrowth of a plant species. Includesstages such as flowering, fruiting, budset, foliar growth, stem elongation,etc.SELECTIVITY: The degree to which anherbicide controls target plant specieswith minimal injury to non-target (orconifer) species.SURFACTANT: A substance added to aspray mixture to decrease surface ten-s ion.BHERBICIDE EFFECTIVENESS REPORTCarefully collected field data on the effec-tiveness of herbicides are essential to up-dating recommendations on herbicide use.Take data systematically, sampling at least10 plots or observing at least 10 plants perspecies. Report 2nd j data only. Use ad-ditional sheets, if necessary, for furtherremarks.NameAddressPhotocopy this form, complete copy and re-turn information to:Dr. Steven RadosevichCRAFTS, Department of Forest ScienceOregon State UniversityCorvallis, Oregon 97331AffiliationPhoneOPERATIONAL OBJECTIVES: [:]Site prep OPre-burn EJRelease DOther (specify)Location of site Time since disturbancePlease specify units (e.g., lb/acre, gal/acre, lb/100 gal carrier, mI/cut or injection, etc.).HERBICIDE(S) USED: Trade name(s):Amount /UnitsAmount of herbicides is based on: DActive ingredient DAcid equivalent DFormulated productCARRIER: EjWater ODiesel DNone Volume(s) /UnitsADDITIVES: Trade name(s) Volume(s) /UnitsPurpose of additiveSPRAY VOLUMEDATE APPLIED0 Per acre EJPer clump DOtherWEATHER: Temperate range ____to Wind (mph)Humidity range: to Sky condition:APPLICATION METHOD: EJAerial DBackpack JInjection DHack & Squirt DOtherSPRAY PATTERN: DBroadcast OSpot or clump OWaving wand QOtherDAMAGE EVALUATION: Date observed SAMPLING METHODS: EjRoadsideOWalk-through DSystematic plots DOther (specify)Average % Phenology1foliar-injury of plant at ObservationsTARGET SPECIES % Dead (nearest 5%) time of application type2/number2.3.CROP SPECIES1Give code (d = dormant [winter], b = bud swelling, a active growth, e = early dormant [latesummer/fall]); detail pheriology further, if possible.plot, I = individual, C = clumps.LITERATURE CITEDBOHMONT, B. L. 1981. The new pesticideuser's guide. B & K Enterprises, FortCollins, Colorado.FRANKLIN, J. F. and C. 1. DYRNESS. 1973.Natural vegetation of Oregon and Washington.USDA Forest Service General Technical ReportPNW-8. Pacific Northwest Forest and RangeExperiment Station, Portland Oregon.NEWTON, M. and F. B. KNIGHT. 1981. Hand-book of weed and insect control chemicals forforest resource managers. Timber Press,Beaverton, Oregon.WEED SCIENCE SOCIETY OF AMERICA. 1983.Herbicide Handbook, 5th ed. Champaign,Illinois.DISCLAIMERCONVERSION TABLE1 acre (A) =1 pound (Ib) =gallon (gal) =1 quart (qt) =THE AUTHORS0.4047 hectare (ha)0.4536 kilogram (kg)3.785 liters0.946 literSusan G. Conard at the time of this study wasa Research Associate in the Department ofForest Science, Oregon State University,Corvallis, Oregon. She is now an Ecologistwith the Forest Fire Laboratory, USDA ForestService, Riverside, California.W. H. Emmingham is Extension SilvicultureSpecialist, Department of Forest Science,Oregon State University, Corvallis, Oregon.Mention of specific compounds or trade names neither constitutes recommendation for their usenor excludes the possibility that other products or treatments may be equally or more effec-tive. Always read product labels to be sure that the products you purchase are registered fortheir intended use.As an affirmative action institution that complies with Section 504 of the Rehabilitation Actof 1973, Oregon State University supports equal educational and employment opportunity withoutregard to age, sex, race, creed, national origin, handicap, marital status, or religion.FOREST RESEARCH LABORATORY NonProht OrgCOLLEGE OF FORESTRY US PostageOREGON STATE UNIVERSITY PAIDCORVALLIS, OR 97331-5704 Corvallis, OR 9733tPermit No 200ADDRESS CORRECTION REQUESTED

Herbicides for grass and herbaceous weed control in Oregon and Washington

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Herbicides for grass and herbaceous weed control in Oregon and Washington

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