Palmer Amaranth Biology, Identification, And
vis LegleiterBill JohnsonPalmer Amaranth Biology,Identification, and ManagementPalmer amaranth (Amaranthus palmeri) isan aggressive, invasive weed native to thedesert regions of the southwest UnitedStates and northern Mexico. It slowlyinfiltrated the southeast United States andhas become one of the most significantweed pests of cotton and soybean producers.What makes Palmer amaranth such aproblem is that most populations areresistant to glyphosate and ALS herbicides.Recently, Palmer amaranth has beenconfirmed in Indiana (particularly in thenorthwest), Michigan, Ohio, and Illinois.This means Palmer amaranth couldpotentially become a major agronomicweed in Indiana and the Midwest.This publication indicates where Palmeramaranth has been found in Indiana,describes the plant’s biology, provides waysto properly identify it, and offersmanagement strategies.Palmer Amaranth in IndianaIn Indiana, Palmer amaranth was firstconfirmed in the river bottoms of Poseyand Vanderburgh counties. PurdueUniversity researchers collected Palmeramaranth seed from one of the riverbottom fields. In greenhouse settings, theplants from this seed survived applicationsof 20 lbs. ae/acre glyphosate (equivalentof 7 gallons/acre of generic glyphosate).In the fall of 2012, 51 fields across fivenorthwest Indiana counties wereconfirmed to have Palmer amaranth plantpopulations that were not controlled bymanagement tactics used during thatgrowing season. The majority of fields(and the heaviest infestations) wereconfirmed in Jasper County. Many of theobserved fields received multipleapplications of glyphosate and attemptedrescue applications of PPO-inhibitingherbicides (Flexstar , Cobra , UltraBlazer , etc.).Researchers believe Palmer amaranth wasintroduced to northern Indiana in dairy orbeef manure from animals that were fedcotton seed hulls or other feed stocks thatcame from the South that werecontaminated with Palmer seed. The exacttiming of the initial event is unknown, butresearchers estimate that it happened atleast two or three years ago due to theseverity of infestation in multiple fields.Farm equipment, specifically combines,has and will spread Palmer amaranth seed.Wildlife can also spread the seed into new,previously uninfested fields. As of fall2013, Purdue Weed Science confirmed thepresence of Palmer amaranth in 27Indiana counties.Photos by Travis Legleiter, except Figures 10 and 11 by Tom Sinnot, Superior Ag Resources.1
Palmer Amaranth Biology, Identification, and ManagementBiology and ImpactEmerges for an Extended PeriodPalmer amaranth is adaptable and invasive. Evidence ofits adaptability is the success of populations in Michiganand northern Indiana where average temperatures arebelow the preferred temperatures of native Palmerpopulations.The biological distinctions that highlight Palmeramaranth’s success as a weed are described below.Palmer amaranth’s emergence period extends well intothe typical crop season and can, at times, occur aftercrop harvest. During the 2013 Indiana growing season,researchers observed Palmer amaranth emergence fromearly May until mid-September. This emergence periodforces producers to manage the weed throughout theyear, unlike other summer annual weeds that are typically managed only through early summer.Adapts QuicklyAmaranth IdentificationPalmer amaranth has dioecious reproduction, soindividual plants are either male or female, which forcesoutcrossing and genetic diversity. This gives Palmeramaranth the ability to adapt and quickly spreadherbicide resistance genes when selection pressure isapplied (as when producers repeatedly apply singlemode of action herbicides).The first, and often critical, step to managing Palmeramaranth (or any weed) is to scout and identify thespecies that exist in each agronomic field. It is easy tomisidentify Palmer amaranth because it looks similar tothree other common amaranth species: redroot pigweed(Amaranthus retroflexus), smooth pigweed (Amaranthushybridus), and common waterhemp (Amaranthus rudis).The resemblance is especially strong during the seedlingstages of growth.All too often, the amaranths are all called “pigweed” andnot identified properly by species. The populations innorthwest Indiana were misidentified as waterhemp forat least the last couple of years and were not managed asaggressively as the situation demanded.To correctly identify the amaranth species in your field,note the characteristics described below. While thesecharacteristics help differentiate the species, rememberthat the characteristics also can be variable within aspecies even within the same population or field. Dueto this variability, always assess multiple plants withinthe field and remember that more than one amaranthspecies may exist in the field.There are several characteristics that differentiate thethree amaranth species: The presence of hair Leaf shape Petiole length Apical meristem growth pattern Seed head structures Leaf blade watermark The presence of a leaf tip hairUnderstanding these characteristics will help producerscorrectly identify amaranth species, and then determinethe proper management strategies.Produces Lots of SeedPalmer amaranth is a prolific seed producer. Each plantcan produce at least 100,000 seeds when they competewith a crop. In noncompetitive scenarios they canproduce nearly a half million seeds.Distributes Small SeedPalmer amaranth seeds are rather small and thrive inno-till or minimum tillage fields. In those situations,seeds are allowed to stay in their ideal emergence zone:the top inch of soil. Humans easily transport the smallseeds through grain, seed, or feed contamination; or onequipment such as combines.Competes AggressivelyPalmer exhibits aggressive growth and competitivenesswith crops. Under ideal conditions, Palmer amaranthplants can grow 2 or 3 inches per day. Within twomonths, Palmer amaranth plants that emerged on May29, 2013, were more than 6 feet tall at the PurduePalmer amaranth research site. When allowed to competethroughout the growing season, Palmer amaranth cancreate yield losses up to 91 percent in corn (Massinga,et al.) and up to 79 percent in soybean (Bensch, et al.).Herbicide ResistancePalmer populations have evolved resistance to multipleherbicide modes of action, including ALS inhibitors,triazines, HPPD inhibitors, dinitroanilines, andglyphosate. The majority of populations in the Southare ALS-inhibitor- and glyphosate-resistant.2
Palmer Amaranth Biology, Identification, and ManagementPresence of Hairback over the leaf blade to compare the petiole and leafblade lengths (Figures 3, 5, and 9).This is the most consistent and reliable characteristicthat differentiates Palmer amaranth from commonwaterhemp, and it is most evident on the oldest leavesof plant (lowest on the stem). Leaf shape, leafwatermark, and leaf tip hair characteristics will helpconfirm the identity of Palmer amaranth; however,these characteristics are much more variable withinspecies and can make correct identification difficultand frustrating if used alone.Only redroot and smooth pigweeds have hairs (pubescence) on their stems and leaf surfaces (Figure 1). The finehairs will be most noticeable on the stems towards thenewest growth. Palmer amaranth and common waterhemp do not have hair on any surface. Looking for pubescence is a quick and easy way to differentiate redrootand smooth pigweeds from the other two amaranths.Figure 1. Redroot and smooth pigweeds have hairs on theirstems and leaf surfaces. These hairs distinguish them fromcommon waterhemp and Palmer amaranth.Figure 2. A Palmer amaranth leaf blade with extended petiole.Leaf ShapeThe leaf shapes of amaranths can vary quite a bit withina single species; however, there are general shapes thatdistinguish the species (Figures 2-5).Common waterhemp leaves are generally long, linear,and lanceolate.Palmer amaranth leaves are wider and ovate todiamond-shaped.Redroot and smooth pigweed leaves are similar toPalmer leaves and have a round to ovate shape —redroot and smooth pigweed leaves, however, have hairswhile Palmer and common waterhemp leaves do not.Plants that have been sprayed and survived multipleherbicide applications (especially PPO-inhibitors) canexhibit variable leaf shapes that may not correctlyrepresent the species.Figure 3. A Palmer amaranth petiole bent back over the leafblade, demonstrating the length of its petiole.Figure 4. The linear, lance-shaped leaf blade and short petiolecharacteristic of common waterhemp.Petiole LengthThe petiole is the stem-like structure that connects theleaf blade to the main stem. In Palmer amaranth thepetioles (especially on older leaves) will be as long (orlonger) than the leaf blade itself (Figures 2, 7, and 8).The petioles of waterhemp, on the other hand, will beshorter than their long, lance-shaped leaves (Figure 4).A quick way to determine the petiole length is to simplypull a leaf and petiole off a plant and bend the petioleFigure 5. A common waterhemp petiole bent back over theleaf blade, illustrating the length of its petiole.3
Palmer Amaranth Biology, Identification, and ManagementApical Meristem Growth PatternPalmer amaranth’s leaf shape and petiole lengths are theresult of the growth pattern of the apical meristem,which grows to capture as much light as possible. Thisresults in a rosette-like appearance as you look directlydown from the top of the plant (Figure 6A). Thisgrowth pattern and rosette appearance is oftencompared to that of a poinsettia.The short petioles and long linear leaves of commonwaterhemp form a less patterned rosette appearancewhen observed from above (Figure 6B).Figure 7. Young Palmer amaranth seedlings exhibit an extendedpetiole on the first true leaves.AFigure 8. A Palmer amaranth seedling. Note the extendedpetiole on the first true leaves.BFigure 9. Note the petiole of this Palmer amaranth seedling islonger than the leaf blade when bend back over the blade.Figure 6. These photos show the leaf shapes and apicalmeristem growth patterns of Palmer amaranth (A) andcommon waterhemp (B). Also note the long petioles of thePalmer amaranth plant, which extend the lower leaves outfrom the shadow of the upper leaves.4
Palmer Amaranth Biology, Identification, and ManagementSeed Head StructuresAlthough one should identify weeds before the plantsreach reproductive stage, it can be useful to look at seedhead structures of escaped weeds to help identify thespecies.Palmer amaranth females have a long main terminalseed head that can reach up to 3 feet long (Figures 10and 11). Palmer amaranth female seed heads also havestiff, sharp bracts that give the seed heads a pricklyfeeling when touched.Common waterhemp has multiple branched seed headsthat are similar in length and lack the stiff, prickly bracts.Figure 10. A Palmer amaranth plant growing in soybean withmultiple terminal seed heads.Leaf Blade WatermarkThe leaves of some (but not all) Palmer amaranth plantshave a white watermark shaped like a chevron or V(Figure 12). This mark is not present on commonwaterhemp, but use this mark only to verify anidentification of Palmer amaranth since not all Palmerplants will express this characteristic.Leaf Tip HairFigure 11. A Palmer amaranth seed head measuring close to30 inches long.You can use the presence or lack of a singular hair in theleaf tip notch to help distinguish Palmer amaranth andcommon waterhemp (Figure 13), although waterhempin the western Corn Belt sometimes has the leaf tip hair.To date, researchers have observed Palmer amaranthplants in Indiana have this single leaf tip hair, whilecommon waterhemp plants do not.It’s important to note that the single hair does notappear on all Palmer plants or Palmer plant leaves, butcan typically be found on the first two or three trueleaves. Because this characteristic is so variable, use itonly to help confirm the identity of Palmer amaranthalong with the other characteristics, particularly petiolelength.Figure 12. Some Palmer amaranth leaves have white chevronor V-shaped watermarks.Spiny Amaranth: A CommonMisidentificationThe presence of stiff, pointy bracts on the female seedhead and leaf axils can lead to confusing Palmeramaranth with spiny amaranth or spiny pigweed(Amaranthus spinosus). Spiny amaranth is predominantlya weed of pastures, livestock holding pens, and feedingareas; it is rare in agronomic fields. Spiny amaranth hasa bushy growth pattern and exhibits the spiny bractsthroughout its life cycle, whereas Palmer amaranthexhibits the bracts only at maturity and duringreproductive stages.Figure 13. Some Palmer amaranth plants have a single hair inthe leaf tip notch.5
Palmer Amaranth Biology, Identification, and ManagementIn a heavily infested field, this practice can reduce thePalmer amaranth population up to 50 percent. Deep tillonly once, because the buried seed will remain viable upto five years and will redeposit in the top layer of soil ifyou deep till again within that time. Long-term no-tillproducers must weigh the weed control benefits oftillage against the economic and soil-structure benefitsof their no-till system.Palmer Amaranth ManagementOnce Palmer amaranth has been properly identified in afield, the next step is to develop a proactivemanagement plan. The main management goals shouldbe to reduce early-season competition with crop plantsand prevent all plants from producing seed and to avoidspreading the weed to other areas.Indiana producers who encounter Palmer amaranth shouldtreat the population as if it is ALS- and glyphosateresistant — that’s because the original transplanted seedlikely came from the South, where the majority of Palmerpopulations are resistant to these herbicides. Again, themost crucial step is to scout fields dilligently and properlyidentify Palmer amaranth when it first appears.Palmer amaranth has only recently been confirmed inIndiana. Purdue Weed Science has conducted limitedresearch on its management. The recommendationsprovided here are based on the short-term research ofPurdue and recommendations from researchers in theSouth and Michigan.Consider combining cultural practices and herbicideprograms for the most effective Palmer amaranthmanagement. Palmer is a very aggressive and adaptiveweed, and management programs that rely on a singlemode of action (such as glyphosate as the only postherbicide) will typically be ineffective at completelycontrolling the weed.Plant a Cereal Rye Cover CropA properly managed and crimped cereal rye cover cropcan provide a mulch that will suppress Palmer amaranthemergence. The majority of research on crimped cerealrye cover crop suppression on Palmer amaranth hasbeen combined with deep tillage; hence, the cover cropis used for its weed suppression capabilities and not thesoil health benefits that cover crop advocates oftenpromote. No other cover crops have been extensivelystudied for use to suppress Palmer amaranth.Hand WeedIn severe infestations in southern U.S. cotton fields andsome Indiana soybean fields, producers have resorted tohiring hand weeding crews to remove Palmer amaranth.It is important to note that weeds should be pulled andtaken out of the field and composted or burned. Plantsthat are laid on the soil in the field will reroot andcontinue to grow and produce viable seed.Monitor Ditches and BordersCultural PracticesTake care to control Palmer amaranth plants in ditchesand field edges. In fall 2012, Purdue weed scientistsidentified Palmer amaranth scattered along multipleroadside ditches in northwest Indiana. Although theseplants did not compete with field crops, they still helpspread of the population through pollen and seed.Rotate CropsAlthough it’s not a new concept to rotate corn andsoybean, rotating fields to corn allows producers to useherbicides with additional modes of action that willcontrol Palmer amaranth. Rotation also helps slowfurther resistance issues and preserves current herbicidetools. In highly infested fields, consider growing cornfor at least two years to maximize Palmer control.Although, as noted below, exercise caution to preventresistance to corn herbicides.Harvest Heavily Infested Fields LastBecause it is so small, Palmer amaranth seed dispersesand spreads quickly, especially in machinery. Sincecombines are one of the largest contributors to thespread of Palmer amaranth seed, consider harvestingfields or field sections that have heavy Palmer amaranthinfestations last.Doing so will help keep the seed in these areas. Afterharvest, clean the combine as best as possible to assureseed will not be spread during the next harvest (this willbe a meticulous and difficult process).Practice Deep TillageDeep tillage (moldboard plow) will bury the smallPalmer amaranth seed below its preferred emergencedepth. Deep tillage will not provide complete control,but will reduce the number of seeds that can emergefrom the top 1 inch of soil.6
Palmer Amaranth Biology, Identification, and ManagementTable 1. Herbicides that provide pre-emergence control of Palmer amaranth in corn.Trade Name(s)Aatrex and othersbActive IngredientSite of ActionSite of Action Group #aatrazinePSII-inhibitorpyroxasulfoneLong chain fatty roxasulfoneLong chain fatty icep II Magnum ,Brawl II ATZ , and Cinch ATZ atrazinePSII-inhibitor5S-metolachlorLong chain fatty acid-inhibitorDegree Xtra , Fultime ,Harness Xtra , and Keystone atrazinePSII-inhibitoracetochlorLong chain fatty arbazoneALS-inhibitor2S-metolachlorLong chain fatty acid-inhibitor15pyroxasulfoneLong chain fatty PSII-inhibitor5dimethenamid-PLong chain fatty acid-inhibitor15dimethenamid-PLong chain fatty rLong chain fatty acilPPO-Inhibitor14dimethenamid-PLong chain fatty acid-Inhibitor15pyroxasulfoneLong chain fatty acid-Inhibitor15Anthem Anthem ATZ Balance Flexx Corvus Dual II Magnum and Cinch Fierce Guardsman Max and G-Max Lite Outlook Lexar and Lumax Verdict Zidua Classification system using numbers for each specific site of action developed by the Weed Science Society of America.Maximum of 2 lbs. ai/A per application and 2.5 lbs. ai/A total for all applications per season.ab751555
Palmer Amaranth Biology, Identification, and ManagementTable 2. Corn herbicides that provide post-emergence control of Palmer amaranth.Trade Name(s)Active IngredientSite of ActionSite of Action Group #avarious2,4-DGrowth regulator4Aatrex and othersbatrazinePSII-inhibitor5Callisto mesotrioneHPPD-inhibitor27Banvel , Clarity , SterlingBlue , and othersdicambaGrowth etolachlorLong chain fatty PS-inhibitor9S-metolachlorLong chain fatty acid-inhibitor15mesotrioneHPPD-inhibitor27Impact and Armezon topramezoneHPPD-inhibitor27Laudis tembotrioneHPPD-inhibitor27Liberty dglufosinateGlutamine synthesis inhibitor10dicambaGrowth regulator4diflufenzopyrAuxin transport19Callisto Xtra Capreno Expert cHalex GT c15Status Classification system using numbers for each specific site of action developed by the Weed Science Society of America.Maximum of 2 lbs. ai/A per application and 2.5 lbs. ai/A total for all applications per season.cRoundup Ready corn hybrids only.dLiberty Link corn hybrids only.ab8
Palmer Amaranth Biology, Identification, and ManagementHerbicide Control in CornHerbicide Control in SoybeanThere are a number of herbicides available in corn thateffectively control Palmer amaranth and offer alternatemodes of action to incorporate into your herbiciderotations. In highly infested fields, growing corn formultiple years can be effective in reducing Palmerpopulations. However, when growing corn for multipleyears, take care to not rely heavily on single modes ofaction because atrazine- and HPPD-resistant Palmeramaranth populations have previously been confirmed.Tables 1 and 2 outline the products available for preemergence and post-emergence use in corn. The tablesalso provide the active ingredients and sites of action forthese products. Use these tables (along with knowledgeof other weeds present) to formulate an effectiveherbicide program that maximizes the number of sitesof action to delay resistance. Also, be aware that amaximum application of atrazine is 2 lbs./acre of activeingredient (ai) and the total of all applications cannotexceed 2.5 lbs. ai/acre.In soybean the number of herbicides available toreplace glyphosate for Palmer amaranth control islimited. Furthermore, the herbicides must be appliedat appropriate weed sizes for consistent control. Themajor herbicide limitation occurs with post-emergenceproducts, so producers must take advantage of theavailable burndown and residual products.Start With a Clean FieldStart with a clean field (either with tillage or anherbicide burndown) as the first key to successfulPalmer amaranth management in soybean (see Table 3).Burndown treatments of glyphosate 2,4-D orglyphosate dicamba can be inconsistent on Palmerlarger than four inches. Researchers in Tennessee havefound that gramoxone metribuzin is the mostconsistent burndown, even on large Palmer plants.Producers may have to consider a two-pass burndownbecause gramoxone metribuzin can be weak on winterannuals that may also exist in the field.Table 3. Herbicide products and tank mixes for burndown of Palmer amaranth prior to soybean planting.Trade Name(s)or Tank MixActive IngredientSite of ActionSite of Action Group #aglyphosateEPSPS-inhibitor92,4-DGrowth regulator4glyphosateEPSPS-inhibitor9dicambaGrowth regulator4paraquatPSI-electron divertermetribuzinPSII-inhibitorLiberty dglufosinateGlutamine synthesis inhibitor10Sharpen /OpTill /OpTillPRO /Veridct glyphosate, Liberty ,Gramaxone d,esaflufenacilPPO-inhibitor14glyphosate or glufosinate orparaquatEPSPS-inhibitor or glutaminesynthesis inhibitor orPSI-electron diverterglyphosate 2,4-Db,c,dglyphosate Clarity b,c,d22Gramoxone Dimetric b59 or 10 or 22Classification system using numbers for each specific site of action developed by the Weed Science Society of America.Specific trades names are used only for clarification. Multiple glyphosate, 2,4-D, dicamba, and metribuzin products are available for use and are equally effective on Palmer amaranth.cBurndown applications containing 2,4-D or dicamba must be applied 7-28 days before planting depending on product and rate. Refer to labels for specific pre-plant intervalsdMust be applied to Palmer amaranth that is 4 inches tall or shorter to achieve maximum consistent control.eDo not apply saflufenacil products with sulfentrazone or flumioxazin as a tank mix or sequential application within 30 days of planting.ab9
Palmer Amaranth Biology, Identification, and ManagementTable 4. Herbicides that provide pre-emergence control of Palmer amaranth in soybean.Trade Name(s)Active IngredientSite of ActionSite of Action Group tor5S-metolachlorLong chain fatty onALS-inhibitor2metribuzinPSII-inhibitor5Dual II Magnum and Cinch S-metolachlorLong chain fatty acid-inhibitor15Dimetric , TriCor , and othersmetribuzinPSII-inhibitor5pyroxasulfoneLong chain fatty chlorLong chain fatty acid-inhibitor15alachlorLong chain fatty nPSII-inhibitor5S-metolachlorLong chain fatty acid-inhibitor15dimethenamid-PLong chain fatty acid-inhibitor15dimethenamid-PLong chain fatty apyrALS-inhibitor2S-metolachlorLong chain fatty acid-inhibitor15fomesafenbPPO-inhibitor14Prowl pendimethalinMicrotubule inhibitor3Valor flumioxazinPPO-inhibitor14Valor XLT , Gangster ,Enlite , and Envive ua pyroxasulfoneLong chain fatty acid-inhibitor15Authority Assist /XL /First /Maxx , and Sonic Authority MTZ Boundary Canopy Fierce Intimidator Intrro , Lasso , and Micro-Tech Matador Outlook Optill PRO Prefix Classification system using numbers for each specific site of action developed by the Weed Science Society of America.A total of 0.313 lb./A (north of I-70) or 0.375 lb./A (South of I-70) of fomesafen is allowed to be applied per season.ab10
Palmer Amaranth Biology, Identification, and ManagementProducers also need to be aware of the plantingrestrictions that come with several burndown programs.Burndowns containing 2,4-D or dicamba require apre-plant interval of seven to 28 days, depending on theproduct, rate, and for dicamba, when the firstprecipitation event occurs after application.Saflufenacil products (Sharpen , OpTill , OpTill PRO ,Verdict ) for Palmer or winter annual burndown requirea 30-day pre-plant window if the producer will use aPPO-inhibiting residual (such as flumioxazin orsulfentrazone).With these restrictions, it may mean you will have tomake multiple passes over a field in the spring toeffectively burn down existing Palmer, and then apply aresidual herbicide as close to planting as possible.will reduce the selection pressure of the few postemergence herbicide options.Apply residual herbicides as close to soybean planting aspossible to maximize product activity in the crop. Fallor early spring residual herbicide applications providevery little to no Palmer amaranth control.Table 4 lists all the soybean products that providePalmer amaranth control or suppression — althoughthe level of suppression varies by product. Purdue WeedScience research has shown that products with the activeingredients flumioxazin or sulfentrazone provide thehighest level of control when applied alone; however,even these herbicides will begin to break down two tothree weeks after application.Products that contain metribuzin, S-metolachlor,pyroxasulfone, and dimethenamid-P will providemarginal suppression of Palmer amaranth; however, theseproducts will strengthen a residual program when appliedin combination with flumioxazin or sulfentrazone.Research indicated that the most robust residualprograms combined two or three of these activeingredients either in tank mixes or premixes. Productlabels may restrict tank mixes; always refer to productResidual HerbicidesResidual herbicides should be the foundation of allPalmer amaranth herbicide control programs in soybean(see Table 4). There are a variety of residual soybeanherbicides that will control Palmer amaranth at itsweakest point (emergence) and substantially reduce thenumber of plants requiring a post-emergenceapplication. Using residual herbicides to manage PalmerTable 5. Soybean herbicides that provide post-emergence control of Palmer amaranth that is 4 inches tall or less.Trade Name(s)Active IngredientSite of ActionSite of Action Group #aS-metolachlorLong chain fatty eEPSPS-inhibitor9Cobra and Phoenix e synthesis inhibitor10Prefix bReflex /Dawn andFlexstar /Rhythm Flexstar GT dClassification system using numbers for each specific site of action developed by the Weed Science Society of America.Prefix has both post-emergence control and residual activity.cA total of 0.313 lb./A (North of I-70) or 0.375 lb./A (South of I-70) of fomesafen is allowed per season.dRoundup Ready soybean varieties only.eLiberty Link soybean varieties only.ab11
Palmer Amaranth Biology, Identification, and Managementlabels before tank mixing products. Remember, manyof these active ingredients and combinations pose cropinjury risk — weigh the potential risk for injury againstthe risk of Palmer amaranth escapes.Post-emergence (Layby) ResidualsAlthough pre-emergence residuals are the foundation ofPalmer amaranth herbicide programs, these productswill not last the entire season — so Palmer plants willcontinue to emerge. Add a residual herbicide (such asDual II Magnum , Warrant , or Outlook , or Zidua )to your post-emergence application to add residualactivity into the latter parts of the season (see Table 6).Remember, pre-emergence products do not controlemerged plants and must be tank mixed with one ofthe post-emergence options mentioned above.Post-emergence Herbicide TimingPost-emergence herbicides in soybean are limited (seeTable 5) to PPO-inhibiting herbicides and Liberty (Liberty Link beans only). The timing of theseproducts is key for effective Palmer amaranth control.The consistency and overall control of the PPOinhibitors and Liberty is dramatically decreased oncePalmer amaranth plants are taller than 4 inches.Soybean producers in the South often plow under andreplant soybean once Palmer is taller than 4 incheswithout an effective post-emerge herbicide application.Multiple Applications and Sites of Action (SOA)The days of one- and two-pass single mode of actionsoybean programs are gone. Producers should acceptthis fact when managing a Palmer amaranth-infestedfield. Producers will have to make multiple applicationsbefore and after planting. Producers should also avoidapplying any single herbicide product or multipleproducts with the same mode of action more than twicein a growing season to avoid conferring resistance to thefew remaining products left to control Palmer amaranthin soybean.Tables 3-6 outline the products available for effectivecontrol of Palmer amaranth at burndown, pre-emergence,and post-emergence, and provide the sites of action ofeach product. Use these tabl
least two or three years ago due to the severity of infestation in multiple fields. Farm equipment, specifically combines, has and will spread Palmer amaranth seed. Wildlife can also spread the seed into new, previously uninfested fields. As of fall 2013, Purdue Weed Science confirmed the presence of Palmer amaranth in 27 Indiana counties. WS-51
Land Stewardship and Iowa State University o Recognition of the need for collaborative efforts to combat weed resistance In Harrison County o Fall 2015: Palmer amaranth went to seed o 2016: local effort to change noxious weed law o Palmer amaranth found in CRP seedings o 2017: Palmer amaranth added to Iowa noxious weed law
animation, biology articles, biology ask your doubts, biology at a glance, biology basics, biology books, biology books for pmt, biology botany, biology branches, biology by campbell, biology class 11th, biology coaching, biology coaching in delhi, biology concepts, biology diagrams, biology
Oct 11, 2018 · super foods, such as Amaranth: a super crop of this millennium with high nutraceutical values. Amaranth can be considered as a “super . This mini review provides information about the composition, antioxidant properties, and potential medical benefits of “Amaranth a . Lutein 2
linoleic (or omega-6) fatty acid (25-62%) and alpha-linolenic (or omega-3) fatty acid (0.3-2.2%). 5. Omega-3 and omega-6 fatty acids are two essential fatty acids which need to be obtained from a diet. 7. Amaranth oil extracted from grain amaranth may reduce the amount of blood choles
transportation, propagation, or sale of this plant is allowed. The intent of the Minnesota Noxious Weed Law is totarget the species . In 2011, the University of Tennessee presented the challenges of identifying and managing Palmer amaranth to the University of Minnesota (UMN) Extension, which initiated the first of .
an effective spot treatment method. Flame Palmer making sure all above ground material is severely wilted or charred. In cases where adult plants were allowed to produce seed, flame the surrounding soil in an effort to heat and destroy the seed. Flaming to kill
Palmer, La Toya, Monique 7/25/2013 Needs an ECF Account Palmer, Lucas, K. 12/2/2009 Has an ECF Account Palmer, Mary, Jane 5/26/1998 Needs an ECF Account Palmer, Matthew, C. 12/6/2006 Needs an ECF Account Palmer, Michael, Paul 2/28/2011 Has an ECF Account
When recording archaeological finds using illustration, it is vital that you look very closely at the features visible on the objects. It is also important to look at colours, textures and materials. The ‘potato game’ is designed to get children looking at everyday objects that are usually taken for granted and spotting small features that make them unique. The game will also develop .
