Canada Thistle

Overview

Canada thistle, also known as Cirsium arvense, is a perennial, herbaceous weed notorious for its detrimental effects on various crops, including corn.

Canada thistle poses a significant threat to corn crops due to its competitive nature and rapid spread. It competes with corn for vital resources such as water, nutrients, and light, leading to potential reductions in yield and quality.

Canada thistle impacts various parts of the corn plant:

• Roots: Canada thistle's extensive root system competes with corn for water and nutrients, potentially leading to stunted growth and reduced yield. • Stems and leaves: The thistle can overshadow corn plants, blocking sunlight and inhibiting photosynthesis. This can result in leaf yellowing and weakened stems. • Ears: Reduced photosynthesis and nutrient uptake can lead to underdeveloped ears with fewer kernels.

Canada thistle can also affect the overall physiology of the corn plant. The competition for resources can induce stress, making the corn plant more susceptible to diseases and pests. Additionally, the physical presence of the thistle can disrupt the pollination process, further reducing yield.

(Image Credit: Phil Westra, Colorado State University, Bugwood.org)

Canadian Thistle in Corn

How to Identify Canada Thistle

Canada thistle is a towering plant, standing 1–1.5 meters tall. Several markers can assist in identifying Canada thistle in your cornfield:

  1. Leaf structure: Canada thistle leaves are alternate, lance-shaped, and feature spiny, toothed edges. They exhibit a dark green hue on top and a lighter green underneath.

  2. Flower heads: The flower heads are small, typically purple or white, and cluster at the plant's apex.

  3. Stem: The stem of the Canada thistle is smooth, grooved, and branches at the top.

  4. Root system: The plant's root system is deep and extensive, reaching up to 3 meters into the soil. It poses a challenge for control once it establishes itself.

Geographic Impact of Canada Thistle

This invasive species, native to Europe and Asia, has migrated and now proliferates in many agricultural fields across Canada and the United States.

Canada thistle thrives under various conditions but is most frequently found in disturbed soils, such as those in agricultural fields, roadsides, and pastures. It is a resilient plant that can withstand a broad range of soil types and climates.

Timing of Canada Thistle

During the growing season, Canada thistle usually emerges in early spring and continues to grow throughout the summer. Flowering typically occurs from June to October. However, its extensive root system allows the plant to regenerate from root fragments at any point during the growing season.

It is crucial for farmers and agricultural professionals to identify this weed early in the growing season and implement appropriate control measures to minimize its impact on yield and crop quality.

How to Manage Canada Thistle in Corn

USA

The best way to control Canada thistle is with effective, systemic herbicides. The best time to apply in corn is mid-to-late July, when the majority of weeds have emerged. Apply Stinger when thistles are 4 inches tall or taller and before bud stage. Apply glyphosate in the bud stage.

Post-Emergence

  • On glyphosate-resistant corn: glyphosate like Willowood Glypho 5

  • On all corn: clopyralid-based products such as Bite*

Always remember to read and follow the product label instructions for accurate application rates and guidelines specific to your location and crop conditions.

Willowood Glypho 5 Tote

Disclaimer

© 2014 - 2024 Farmer's Business Network, Inc. All rights Reserved. The sprout logo, “Farmers Business Network”, “FBN”, “FBN Direct” are trademarks or registered trademarks of Farmer's Business Network, Inc. This content was written by Norm℠, reviewed and edited by Stephanie Nikolopoulos.

This content was generated with the assistance of Norm℠, FBN’s artificial intelligence (AI) Ag Advisor, based on a dataset of information containing general industry best practices and research. The AI model did not use specific external sources to generate this content. Our process involves using AI to aid human subject matter experts with the initial drafting and/or refinement of content.

The information and content provided is believed to be reliable, but its accuracy is not guaranteed. The content is provided for informational purposes only. It is not intended to be a substitute for specific agronomic, business, or professional advice, and should not be relied upon as such. Neither Farmer's Business Network Inc. nor any of its affiliates makes any representations or warranties, express or implied, as to the accuracy or completeness of the statements or any information contained in the material and any liability therefore is expressly disclaimed. If you have any questions or feedback about the content, please feel free to contact us or visit our FAQ (https://www.fbn.com/community/blog/norm-faq).

Every product that labels CANADA THISTLE as a weed, pest, or disease the product can be applied against is shown below. Click any product for label and more information.
2,4-D Amine 42,4-D Amine 42,4-D Amine 4 Herbicide2,4-D LV 42,4-D LV 4 (Albaugh)2,4-D LV 62,4-D LV 6 (Albaugh)4-Speed® XT638 HerbicideAbundit® EdgeAbundit® EdgeAbundit™ Extra (Exclusively Distributed by DuPont)Accent® HerbicideAccolade™ HerbicideAccord® Concentrate HerbicideAccord® XRT HerbicideAccord® XRT II HerbicideAccurate® ExtraAccurate® ExtraAccurate® HerbicideAcuron®Acuron® FlexiAcuron® GTAffinity® BroadSpecAffinity® BroadSpec Herbicide (with TotalSol™)Affinity® TankMixAffinity® TankMix Herbicide (with TotalSol®)Afforia™Agility® SG with TotalSol® Soluble GranulesAgri Star Dicamba HDAim® EC HerbicideAim® EW HerbicideAlecto™ 41SAlligare 2,4-D AmineAlligare 2,4-D LV6Alligare Dicamba 2,4-D DMAAlligare Dicamba 4Alligare Imazapyr 2 SLAlligare Imazapyr 4 SLAlligare MSM 60Alligare Triclopyr 4Alligare Triumph® 22KAlluvex™Ally® Extra SG Herbicide (with TotalSol®)Ally® Extra SG with TotalSolAlly® XPAlly® XPAmber® Custom-Pak™Amine 4 2,4-DAmine 4 2,4-D HerbicideAmine 400 2,4-D Weed KillerAmine 6Antik™ ECAqua Star®Aquamaster®AquaNeat® Aquatic HerbicideArgosArmezon® herbicideArmezon® PRO herbicideArsenal® herbicideArsenal® herbicide Applicators ConcentrateArsenal® PowerLine™ herbicideAtticus Cavallo™ 4 SCAudit® 1:1Audit® 4:1Audit® 75 WDGAutonomy™ HerbicideAutumn™ Super 51 WDG HerbicideAxill Solutions Glufosinate 280SLBallast™Banvel 480 HerbicideBanvel® HerbicideBarrage® HFBarrier® Ornamental Landscaping HerbicideBasagran®Basagran® 5LBasagran® HerbicideBasagran® HerbicideBasagran® HerbicideBasagran® HerbicideBasagran® T&O herbicideBase Camp® Amine 4Base Camp® LV 6Base Camp® MCP EsterBashAzon HerbicideBasis® BlendBattleship® IIIBeacon® HerbicideBestow™ HerbicideBeyond® herbicideBeyond® Xtra herbicideBiscayne™Bison®Bison® HerbicideBiteBOABoomer™ HerbicideBoulder 6.3Brash®Broadloom® HerbicideBroadrange® 55 HerbicideBroadStar® HerbicideBroclean®Broclean® HerbicideBromac®Bromac® AdvancedBronate® Advanced™Brox® 2ECBrox®-MBrox®-M UltraBrozine®Brush-Rhap®Buccaneer® (55467-10)Buccaneer® 5Buccaneer® 5 ExtraBuccaneer® Plus (55467-9)BurnMaster™ HerbicideCaballeroCalibra™Callisto® GTCallisto® XtraCandor® HerbicideCanopy® BlendCanopy® EX HerbicideCanopy® HerbicideCapreno®Capstone® Specialty HerbicideCasoron® 4GCasoron® 4GCelebrity® PlusCelsius® WGCelsius® XtraChange Up™ Selective HerbicideChaparral™ Specialty HerbicideChaser® Turf HerbicideCheetah® HerbicideCheetah® ProCheetah™ Max HerbicideChiptox® MCPAChisum™ HerbicideChlorimuron 25 WDGCimarron® MaxCimarron® Max HerbicideCimarron® Max Part BCimarron® Max Part B HerbicideCimarron® PlusCimarron® PlusCimarron® X-traCinco™Ciramet™ HerbicideCivility™ ExtraClarifier®Clarifier®Clarity® herbicideClash® Selective HerbicideClassic® HerbicideClassic® HerbicideClean Amine®Clean Slate® (Nufarm)CleanWave® HerbicideCleat® 75 WG HerbicideCloak®Cloak® EXCobra® HerbicideColt® ASColt®+Salvo® HerbicideColt®+Sword® HerbicideComet® Selective HerbicideCommando M™Commando™Comply™ HerbicideConfront® Specialty HerbicideCool Power®Cornbelt® 4Lb. AmineCornbelt® 4Lb. Lo Vol EsterCornbelt® 6Lb. Lo Vol EsterCornbelt® SalvanCornerstone K HerbicideCornerstone®Cornerstone® 5 PlusCornerstone® Plus (1381-192)Cornerstone® Plus (524-454-1381)Corsican HerbicideCoyote™Credit® 41Credit® 41 ExtraCredit® 5.4 ExtraCredit® XtremeCrossbow® By United SuppliersCrossbow® HerbicideCrossbow® HerbicideCrossbow® Herbicide (Dow)Crossbow® LCrossbow™ HerbicideCrossroad®Crusher®Crusher™Curio® HerbicideCurtail® HerbicideCurtail® M HerbicideD-638Dagger®Daikon™Dally®De-Amine™ 4De-Ester™LV4Deadbolt®DefiniteDefy® Amine 4Defy® LV-4Defy® LV-6Depth Charge™Derigo® HerbicideDerive 75 DFDerive® 4LDesperado® Selective HerbicideDetail® powered by Kixor® herbicideDetonate® HerbicideDetonate® Herbicide (old version)Diablo® Herbicide (Nufarm)Dicam De-Ester®Dicamba De-Amine®Dicamba DGADicamba DMA SaltDicamba DMA Salt 5Dicamba HD 5Dicamba Max 4Dicamba XPDiCash DGA-4DiFlexx® DUODiFlexx™ HerbicideDimetric® DF 75%Dimetric® EXTDisha DMADistinct® herbicideDMA® 4 IVM HerbicideDoleac™ DMADolerity™ DGADouble HeaderDraft™ HerbicideDrexel Dicamba HerbicideDrexel Mes-O-Sate™Dri-Clean® HerbicideDryphosate 75SGDuPont Accent® QDuPont Matrix® SGDuraCor®Duramax® HerbicideDurango® DMA® HerbicideDurango® DMA® HerbicideDurus®E-2 HerbicideEcomazapyr 2 SLEdict® 2SCEdition® TankmixElement® 3A Specialty HerbicideElement® 4 Specialty HerbicideElevore™ Herbicide Arylex™ ActiveElliptical™ HerbicideEmbed® ExtraEmbed™Engenia HerbicideEnlist Duo™ Herbicide with Colex D TechnologyEnlist One™Envive®Envive® HerbicideEnvy™Envy™ IntenseEnvy™ Six MaxEquip™Escalade® 2Escort® XPEscort® XPEsplAnade® SureET® Herbicide/DefoliantET®X Herbicide/DefoliantEvinco™Expert® HerbicideExpress® Herbicide (with TotalSol®)Express® with TotalSol®Express® XPExtra Credit 5®Facet® L herbicideFallOut™ HerbicideFancyFar ReachFever™Fever™ HerbicideFeXapan™ herbicide Plus VaporGrip™ TechnologyFinale®Finale® XL F-VM herbicideFinale® XL T&O herbicideFinesse® Cereal and FallowFinesse® Cereal and Fallow HerbicideFinesse® Grass & Broadleaf HerbicideFireBallFirstRate® HerbicideFirstRate® HerbicideFive Star®Flumigard™ HerbicideFlumioxazin 51WDG Select™FMC Report® ExtraForeFront® HLForeFront® R&P Specialty HerbicideForesters'® Non-Selective HerbicideForestry Garlon® 4 Specialty HerbicideForestry Garlon® XRT Specialty HerbicideForfeit® 280Formula 40®Four Power Plus®Freelexx®Frequency® herbicideFrontRunner™Full Deck™Gambit® HerbicideGarlon® 3A Specialty HerbicideGarlon® 4 Specialty HerbicideGarlon® 4 Ultra Specialty HerbicideGarlon® XRTGCS 2,4-D LV 6 EsterGCS Clopy 360SLGCS Flumet 80WDGGCS MesoXtra HerbicideGCS Quinclo 4GF-3335Glean XP HerbicideGlean® Fertilizer Compatible HerbicideGlean® XPGlory®Gly Star® 5 ExtraGly Star® GoldGly Star® K-PlusGly Star® OriginalGly Star® PlusGly Star® Pro Grass and Weed KillerGlyfine™ PlusGlyfos® Aquatic HerbicideGlyfos® X-TRA HerbicideGlyphogan® HerbicideGlyphogan® Plus HerbicideGlyphosate 4 PlusGlyphosate 5.4Grapple™Graslan® LGravitas®GrazonNext® HLGrazonPD3™Gunslinger AMPHABITAT® herbicideHalex® GTHardBall®Harmony® Extra SG Herbicide (with TotalSol®)Harmony® Extra SG with TotalSol™Harness® MAX HerbicideHarness® MAX HerbicideHarrow™Hat Trick® Three Way HerbicideHavoc LV-SixHavoc™ LV FourHelmet MaxxHelosate® 75 SGHelosate® Plus AdvancedHerbivore® HerbicideHi-Dep® Broadleaf HerbicideHi-Dep® IVM Broadleaf HerbicideHighNoon™ HerbicideHinge™Honcho® HerbicideHoncho® K6 HerbicideHoncho® K6 Herbicide (Monsanto)Honcho® PlusHornet® HerbicideHornet® WDG Broadleaf Blend HerbicideHorsepower® Selective HerbicideHoss® UltraHuskie® CompleteHuskie® FXHuskie® HerbicideIgnite® 280 SLImazethapyr 2 SLImiFlex™Imitator® 18% ConcentrateImitator® 25% ConcentrateImitator® AquaticImitator® PlusImpact Core®Impact®ImpactZ®Inflame™ 280 SLInflict™Instigate®Interline® HerbicideIntermoc™Invora®Invora™Jacket WDGKasai™KleenUp® Pro HerbicideLandmark® XPLatigo®Laudis® HerbicideLeadoff® HerbicideLeopard™Lexar®Lexar® EZLiberty® 280 SLLiberty® 280 SL HerbicideLifeline®Lifeline® GTLightning® HerbicideLima 6Lineage® Clearstand® HerbicideLo-Vol 4 2,4-D Low VolatileLo-Vol 6 2,4-D Low Volatile HerbicideLock Down™Lock Down™ SCLontrel® Turf and Ornamental HerbicideLow Vol 4 Ester Weed KillerLumax®Lumax® EZLuxxur A HerbicideMad Dog®Mad Dog® 5.4Mad Dog® PlusMaestro® 2ECMaestro® 4ECMaestro® AdvancedMaestro® DMaestro® MAMainline™Makaze Yield Pro®Makaze® HerbicideMalibu™Mamba™Manor® Selective HerbicideMarengo®Marengo®Marengo® GMarksman® herbicideMatrix® FNVMatrix® SGMaverick™ Corn HerbicideMCP Amine 4MCP Ester 4 HerbicideMCPA AmineMCPA Amine 4MCPA Amine 4 (Albaugh)MCPA Ester 4MCPA Ester 4MCPA L. V. 4 EsterMCPA-4 AmineMCPE PhenoxyMe-Try-Buzin™ 4LMe-Try-Buzin™ 75DFMeso Star PlusMesoTryOne™ 4LMesoXtra HerbicideMethod® 240SLMethod® 240SLMethod® 50SGMetolachlor + MesoATZMetribuzin 75Metribuzin 75DFMetricor™ 4FMetricor™ DFMetriflex 4SCMetrixxMetrixx 75DFMetrixx PlusMetrixx SCMezaVue™Milestone® Specialty HerbicideMilestone® VM Plus Specialty HerbicideMilestone® VM Specialty HerbicideMirage® (524-445-34704)Mission® HerbicideMojave 70 EGMongoose™ HerbicideMoxy® 2EMSM 60WDG Select™Nimble®Nimble®Northstar® HerbicideNoventa™ HerbicideNuance® HerbicideNufarm Imazuron™ HerbicideNufarm Leopard™ HerbicideNufarm Polaris® AC Complete HerbicideNufarm Polaris® AC HerbicideNufarm Polaris® HerbicideOctivio™Octivio™ PulseOmni® Brand Metribuzin 75 DFOpensight® Specialty HerbicideOpportunityOptero™Opti-Amine®OpTill® powered by Kixor® herbicideOpTill® PRO Herbicide (Liquid)OpTill® PRO powered by Kixor® herbicideOrchard Clean®Orchard Master® Broadleaf HerbicideOrchard Master® CA Broadleaf 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Ultra®Roundup WeatherMAX® (Monsanto)Roundup WeatherMAX® HerbicideRT 3® HerbicideRT 3® Herbicide (Monsanto)Rugged® HerbicideSaber®Saddle-Up®Sahara® DG herbicideSalvo®Savage® Dry SolubleScorch™Scorch™ EXTScout™ HerbicideSemera® 51.0% WDGSemera™ SCSendero®Sequence®Shar-Max Glyphosate 41% SLSharpen® powered by Kixor® herbicideShieldex® 400SC HerbicideShowdown® HerbicideShredder® 2,4-D LV6Shredder® Amine 4Shredder® MCPAShredder® MCPEShredder™ 2,4-D LV4Shredder™ E-99Sinate® HerbicideSinkerball®Smackdown™Solida® HerbicideSolida® HerbicideSolution Water Soluble®Solve™ 2,4-DSolve™ MCPA EsterSonora™Sparrow™Specticle® FloSpecticle® GSpike® 80DF Specialty HerbicideSpirit® HerbicideSpitfire™ HerbicideSpoiler® HerbicideSpur®Spyder® Selective HerbicideStadia™Stalwart® 2WStalwart® 3WStanza™ HerbicideStatus® herbicideStaunch® IIStaunch™ HerbicideSteadfast®Steadfast® QSteadfast® QSterling Blue® HerbicideSterling® BlueSterling® Blue DGAStigmata™Stinger® HerbicideStinger® HLStoren™Stout®Streamline®Strike Three Ultra® 2Stringent™Strive™Strut®Sunphosate 41%Sunphosate 5 MAX (Wynca)Supremacy® HerbicideSure Power® Selective HerbicideSureGuard® HerbicideSureGuard® SC HerbicideSureStart® HerbicideSureStart® IISurge® Broadleaf Herbicide for TurfSurmise®Surmise® 5Sword®Synchrony® XPT-Pac™ XPT-Square™ HerbicideTahoe® 3A HerbicideTahoe® 4E HerbicideTalinor™Taquet™Tarzec™Tavium® Plus VaporGrip® TechnologyTelar® XPTelar® XPTelone® II Soil FumigantTenacity®Tenkoz® Amine 4 2,4-D (71368-1-55467)Tenkoz® Lo-Vol 4 2,4-D Low VolatileTenkoz® Lo-Vol 4 Solventless HerbicideTenkoz® Lo-Vol 6 2,4-D Low Volatile HerbicideTenkoz® MCPA Broadleaf Amine 4TerraVue™Testify™Tetris™ SGThistrol® HerbicideThreesidual™ HerbicideThrottle® XPThunder®Tide Glufosinate 280 SLTide Hexazinone 2SLTide Hexazinone 75 WDGTide MSM 60 DF HerbicideTopeka®Tordon® 22K Specialty HerbicideTordon® K Herbicide Specialty HerbicideTorment®Torocity™Total TNVTotal® 2.3Total® HerbicideTouchdown HiTech®Touchdown® CTTouchdown® HerbicideTraject™ 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HerbicideWestar®Whetstone™ HerbicideWhiplash™Whiteout® 2,4-DWideARmatch™ HerbicideWideMatch® HerbicideWildCard®WildCard® XTRAWillowood Chlorim 25WDGWillowood Cloran DFWillowood Glufosinate 280SLWillowood Glufosinate 280SL (OT)Willowood Glypho 6Willowood Imazethapyr 2SLWillowood Lactofen 2ECWillowood Mesotrione 4SCWillowood Metribuzin 75DFWillowood Metriosate GTWolverine® AdvancedWolverine® HerbicideXtendimax w/VaporGrip Technology (2020)XtendiMax® With VaporGrip® TechnologyYukon® HerbicideZemax™ Selective HerbicideZidua® PRO powered by Kixor® herbicide