Waterhemp (Amaranthus tuberculatus), a summer annual weed from the pigweed family, has become a significant concern for farmers. Its rapid growth rate, high seed production — a single Waterhemp plant can produce up to a million seeds — and resistance to multiple herbicide classes make it a difficult pest to control.

(Image Credit: Ohio State Weed Lab , The Ohio State University, Bugwood.org)


How to Identify Waterhemp

A tall, erect, branching plant, Waterhemp can tower up to 8 feet. Its long, lance-shaped leaves are typically smooth, exhibiting a waxy sheen, and its hairless stems vary in color from green to red. 

Waterhemp's distinct feature is its small, green flowers that cluster on long, slender spikes at the plant's apex. These spikes can extend to half the plant's length. 

Unlike other pigweed species, Waterhemp plants are either male or female. This contributes to its high genetic diversity and adaptability.

(Image Credit: Aaron Hager, USDA Agricultural Research Service, Bugwood.org)


Geographic Impact of Waterhemp

Predominantly found in the midwestern United States, particularly in Illinois, Iowa, and Missouri, Waterhemp has started to invade other parts of the United States and Canada.

It is commonly found in corn and soybean fields and pastures. It also thrives in disturbed habitats like roadsides.

Timing of Waterhemp Emergence

Waterhemp usually emerges later in the growing season — from late spring to early summer — than other weeds. However, its emergence can continue throughout the growing season, making it a persistent issue for farmers.

How Waterhemp Impacts Corn

Research indicates that corn yield can drop by up to 15% with just one Waterhemp plant per foot of row.

Waterhemp's impact on corn varies depending on the affected corn plant part. The roots are particularly vulnerable as Waterhemp can outcompete corn for soil nutrients — like nitrogen, phosphorus, and potassium — and water. This leads to nutrient deficiencies and reduced plant health.

Waterhemp also affects corn leaves. Its rapid growth allows it to overshadow corn plants quickly, blocking light and reducing photosynthesis, which can result in decreased plant vigor and lower grain yield.

(Image Credit: John D. Byrd, Mississippi State University, Bugwood.org)


How to Manage Waterhemp in Corn

For effective Waterhemp management in corn, these products are recommended: 


Pre-emergence and burndown 


For Enlist herbicide traited corn

Enlist One™  with an application rate of 2.5 to 3.8 pints per acre.

Enlist One™ is an herbicide containing 2,4-D choline salt specifically labeled for use with corn to control Waterhemp. However, Enlist One™ is only labeled for use in corn that has the Enlist herbicide trait, such as PowerCore or SmartStaxEnlist. While you can apply other 2,4-D products, like our GCS LV6, if the corn plant is under eight inches, there is a danger that it could carry in the wind, making the stalk brittle. More information about Enlist One™, including the label and safety data sheet, can be found here.

Always read and follow the specific instructions on the product label for accurate application rates and timing.

How Waterhemp Impacts Soybeans

According to the University of Missouri Extension, even a moderate Waterhemp infestation can slash soybean yields by 44%. 

Waterhemp impacts soybean plants in several significant ways:

1. Resource Competition: As a highly competitive weed, Waterhemp vies with soybean plants for water, nutrients, and sunlight. This competition can stunt growth and reduce yields in soybean plants.

2. Harvesting Interference: Mature Waterhemp plants can disrupt combine operation during soybean harvest, leading to increased harvest time and cost.

3. Herbicide Resistance: Waterhemp's resistance to multiple classes of herbicides complicates its control. This resistance can lead to increased herbicide use, resulting in higher production costs and potential environmental impacts.


How to Manage Waterhemp in Soybeans

Accurate identification, understanding its impact, and implementing effective management strategies are paramount in controlling this persistent weed.

To manage Waterhemp in soybeans, consider these products: 

Following the instructions provided on the labels ensures proper and effective use of these products.

There are also non-chemical approaches to managing this weed. Research at the University of Wisconsin-Madison indicates that narrow row spacing in soybeans helps reduce Waterhemp issues. Combining this method with effective herbicides provides integrated management.


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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.

Every product that labels WATERHEMP as a weed, pest, or disease the product can be applied against is shown below. Click any product for label and more information.
Abundit® EdgeAbundit® EdgeAccolade™ HerbicideAccord® XRT HerbicideAcumen® HerbicideAcuron® GTAgri Star Dicamba HDAim® EC HerbicideAim® EW HerbicideAlecto™ 41SAlligare Dicamba 4Anthem® Flex HerbicideAntik™ ECArrest CSArrest PlusAuthority® MaxxAuthority® XL HerbicideBanvel 480 HerbicideBanvel® HerbicideBicep II MAGNUM®Bicep II MAGNUM® FCBicep Lite II MAGNUM®Boundary® 6.5 ECBrawl II ATZ™Brawl™Breakfree® NXT ATZBuccaneer® (55467-10)Buccaneer® 5 ExtraBuccaneer® Plus (55467-9)Bullet® HerbicideCalibra™Callisto® XtraCanopy® HerbicideCharger MAX® ATZCharger MAX® ATZ LiteCheetah™ Max HerbicideChlorimuron 25 WDGCinch® ATZCinch® ATZ LiteClarifier®Clarifier®Clarity® herbicideClash® Selective HerbicideComply™ HerbicideConfidence®Confidence® XtraConfidence® Xtra 5.6LCornerstone K HerbicideCornerstone®Cornerstone® 5 PlusCornerstone® Plus (1381-192)Cornerstone® Plus (524-454-1381)Corsican HerbicideCorvetteCredit® 41 ExtraCredit® 5.4 ExtraCredit® XtremeCurio® HerbicideDaikon™DefiniteDegree Xtra® HerbicideDegree Xtra® HerbicideDegree® HerbicideDerive 75 DFDerive® 4LDetail® powered by Kixor® herbicideDetonate® HerbicideDetonate® Herbicide (old version)Diablo® Herbicide (Nufarm)Dicamba DGADicamba DMA SaltDicamba DMA Salt 5Dicamba HD 5Dicamba Max 4Dicamba XPDiCash DGA-4DiFlexx® DUODiFlexx™ HerbicideDimetric® DF 75%Dimetric® EXTDimetric® LiquidDisha DMADog Fight™Doleac™ DMADolerity™ DGADrexel Dicamba HerbicideDual II Magnum®Dual MAGNUM®Duramax® HerbicideDurango® DMA® HerbicideDurango® DMA® HerbicideElectra 5.6LEngenia HerbicideEnlist Duo™ Herbicide with Colex D TechnologyEnlist One™Envy™Envy™ IntenseEnvy™ Six MaxEquip™EssensaEtcetraExpert® HerbicideExtreme® herbicideFarmer's First™ Acetochlor 7EC HerbicideFearlessFearless Xtra 5.6LFearless Xtra HerbicideFireBallFirstRate® HerbicideFirstRate® HerbicideFlexstar® GT 3.5Four Power Plus®Framework® 3.3 EC HerbicideFrontRunner™Galvan®GCS Acetochlor 7ECGCS Flumet 80WDGGCS S-Metolachlor 82.4% ECGF-3335Glory®Glory® 4LGly Star® 5 ExtraGly Star® GoldGly Star® K-PlusGly Star® OriginalGly Star® PlusGly Star® Pro Grass and Weed KillerGlyfine™ PlusGlyfos® X-TRA HerbicideGlyphogan® HerbicideGlyphogan® Plus HerbicideGlyphosate 4 PlusGoal® 2XL HerbicideGoal® 2XL HerbicideGoalTender® HerbicideGoalTender® HerbicideHarbinger® Herbicide (241-337-34704)Harness® 20G HerbicideHarness® HerbicideHarness® Herbicide (Monsanto)Harness® XtraHarness® Xtra (Monsanto)Harness® Xtra 5.6 LHarness® Xtra 5.6LHeadwinHelena® PendimethalinHoncho® HerbicideHoncho® K6 HerbicideHoncho® K6 Herbicide (Monsanto)Honcho® PlusHornet® HerbicideHornet® WDG Broadleaf Blend HerbicideHorsepower® Selective HerbicideHoss® UltraImitator® PlusInstigate®Intrro®Jacket WDGKatagonKleenUp® Pro HerbicideLadem ATLariat®Ledger™ HerbicideLexar® EZLinex® 4L Agricultural HerbicideMad Dog® 5.4Mad Dog® PlusMakaze Yield Pro®Makaze® HerbicideMatador®Matador®-SMaxtron™ 4SCMaxunitech Carfentrazone + Sulfentrazone SEMe-Too-Lachlor™Me-Too-Lachlor™ MTZMe-Try-Buzin™ 4LMe-Try-Buzin™ 75DFMedal® ECMedal® II ATMedal® II ATZMedal® II ECMetalliS™ MTZMetalliS™ PFXMetribuzin 75Metribuzin 75DFMetricor™ 4FMetricor™ DFMetriflex 4SCMetrixxMetrixx 75DFMetrixx PlusMetrixx SCMicro-Tech®Mirage® (524-445-34704)Moccasin® MTZNektron™ SCOmni® Brand Metribuzin 75 DFOpTill® powered by Kixor® herbicideOpTill® PRO Herbicide (Liquid)OpTill® PRO powered by Kixor® herbicideOptogen™Parallel® PlusPayback ATZPhenomenon™ DuoPin-Dee™ 3.3 ECPraxis PlusPrefix® HerbicidePresidual™ HerbicidePriority® MTZProwl® 3.3 EC herbicideProwl® H2O herbicidePylex™ herbicidePyrimax™ 3.2 L HerbicidePysonex™ HerbicidePython® HerbicidePython® WDG HerbicideQuake™ HerbicideQuinark™ EWRancor™ 4 FRancor™ 75 DFRascal® PlusRealm® QRealm® QReflex®Reptile WDGRequire® Q (mp)Resist™ HerbicideRestraint™ herbicideRevitonRevulin® QRevulin® QRifle®Roundup PowerMAX®Roundup PowerMAX® 3 (Monsanto)Roundup PowerMAX® 3 HerbicideRoundup PowerMAX® HerbicideRoundup PowerMAX® IIRoundup PowerMAX® II (Monsanto)Roundup Ultra®Roundup WeatherMAX® (Monsanto)Roundup WeatherMAX® HerbicideRowel™ FX HerbicideRT 3® HerbicideRT 3® Herbicide (Monsanto)SalvusSatellite® 3.3 herbicideSatellite® FlexSatellite® HydroCap herbicideScorch™ EXTSequence®Shar-Max Glyphosate 41% SLShark® EWSharpSharpen® powered by Kixor® herbicideShowdown® HerbicideSmackdown™Sonalan® 10G HerbicideSonalan® HFP HerbicideSpartan® ChargeStalwart® Xtra HerbicideStalwart® Xtra LiteStanza™ HerbicideStaple® LXStatement™ HerbicideStaunch® IIStaunch™ HerbicideStealth CompleteSterling Blue® HerbicideSterling® BlueSterling® Blue DGAStoren™Strut®Sunphosate 41%Sunphosate 5 MAX (Wynca)SureStart® HerbicideSureStart® IISynchrony® XPTackle® HerbicideTailwind™Testify™Threesidual™ HerbicideThunder Master®Topeka®Torment®Touchdown HiTech®Touchdown® CTTouchdown® HerbicideTraject™ 4SCTraxion®Treevix® powered by Kixor® herbicideTriangle® HerbicideTribal™TriCor® 4FTriCor® DFTrifluence™TripleFLEX® II HerbicideTripleFLEX® II HerbicideTripleFLEX™ HerbicideTripzin™ ZCTrisidual™ HerbicideTrizmet™ IITrizmet™ LiteUP-Front™Valor® XLT Soybean HerbicideVanquish® HerbicideVerdict® powered by Kixor® herbicideVision™ HerbicideWarrant HerbicideWarrant Herbicide (CS)Willowood Chlorim 25WDGWillowood Cloran DFWillowood Glypho 6Willowood Metribuzin 75DFWillowood Sulfen ChlorimYukon® HerbicideZeus® Prime XCZidua® HerbicideZidua® SC herbicideZone 4FZone HerbicideZone Maxx Herbicide