b'FROM MISSOURI TO MANITOBAalways) have a more oblong leaf and it can (but not always) be a darker, shiny green. When plants are more mature we can look WATERHEMP IS HERE TO STAY attheseedheads,herewecanreallysee somedifferences.Redrootpigweedhasa thick and compact bottlebrush-shaped seed-Know your enemy head while waterhemp has a skinnier, long and snaky seedhead. The most definitive way to know which pigweedyouhavethroughDNAanalysis. Samples can be sent to the Pest Surveillance By Kim Brown Initiative lab in Winnipeg for testing. Provincial Weeds Specialist, Manitoba AgricultureThese are common agricultural weeds.More recent introduction of problematic species likeTop Left:Waterhemp seedheadBy Dennis Lange waterhemp (Amaranthus tuberculatus), smoothWhen waterhemp is Top Right:Redroot pigweed seedhead.Provincial Pulse and Soybean Specialist, pigweed(Amaranthushybridus)andPalmer Manitoba Agriculture amaranth (Amaranthus palmeri) is concerning.confirmed or even Middle Right:Hairy and smooth stems.T he first confirmed waterhemp plantWaterhemp,smoothpigweedandPalmersuspected you must PHOTOS: MANITOBA AGRICULTUREamaranthareaggressivelycompetitiveand was discovered in Manitoba in 2018resistant to multiple herbicides.remove the plants Bottom Right:PHOTO: OMAFRAand now five years later waterhempWithsomanydifferentpigweedsinbefore they set seed.has been found in twenty rural municipali- Manitoba we need to identify which spe- They are prolific seed ties (RMs). While we continue to find fieldsciesareinourfields.Thesespecieslook withonlyoneortwowaterhempplantsvery similar when young and its difficultproducers and a singleKelsey Waterhemp Distribution in Manitobathere are some fields with many plants. 2023to tell them apart. One of the first ways towaterhemp has enough seed(Amaranthus tuberculatus)saw numerous infestations particularly in thetell the difference is to feel the stem. If it RMs of de Salaberry and Emerson-Franklin.feels rough its very likely redroot pigweed.(up to one million seedsThereareseveralpigweedspeciesinMost of the other pigweeds have hairless,per plant) to infestManitoba such as redroot pigweed (Amaranthussmoothstems.Youmaybeabletoseea retroflexus),Powellspigweed,(Amaranthusfew fine hairs on the stem but you cant feelentire fields if left behind.powellii, known elsewhere as green pigweed)them.Theleavesofmostpigweedslook andtumblepigweed(Amaranthusalbus).very similar, but waterhemp can (but notMountainMinitonasSwan BowsmanValley 2023 by MunicipalityWestMountain confirmedRoblin Ethelbert Mossey River Grahamdale Gilbert LakeshorePlains DauphinGrandviewWest BifrostRiding Ste. Interlake Fisher RivertonMountain RoseWestRussell Rossburn McCreary Alonsa VictoriaBinscarth Coldwell Armstrong Gimli BeachHarrison GlenellaEllice Yellowhead Park Clanwilliam Lansdowne St. Alexander When waterhemp is confirmed or even EricksonArchie Prairie Minto Rosedale Westlake Laurent Rockwood St. Clements Lac du suspected you must remove the plants before View Gladstone BonnetHamiota Oakview Odanah Woodlands St. Andrews Brokenhead theysetseed.Theyareprolificseedpro-Portage St.Wallace Riverdale Elton North Cypress North La Prairie Franois Rosser West St. Paul Whitemouth ducers and a single waterhemp has enough Xavier East St. PaulWoodworth Langford Norfolk Cartier Winnipeg Springfield seed (up to one million seeds per plant) to HeadingleyPipestone Sifton Whitehead Cornwallis Glenboro Victoria Norfolk Grey Macdonald Ritchot Tach Ste. Reynolds infest entire fields if left behind. Pull or dig Souris Oakland South TreherneGlenwood Wawanesa Cypress Dufferin Hanover Anne up plants and remove them, try to get all Grassland Prairie Lorne Morris DeLatherootsastheycanregrow.Donotcut Two Borders Deloraine Lakes Argyle Thompson Roland Salaberry Broquerie waterhemp as they will regrow and set seed. WinchesterBrenda Boissevain Killarney Cartwright Louise Pembina Stanley Rhineland Emerson Stuartburn Piney Under NO circumstances should you put it Morton Turtle Roblin Montcalm FranklinWaskada Mountain through the combine as combines are great Author: Manitoba Agriculture 1:2,300,000Source: MB Ag Confirmation 0 25 50 100Waterhemp and other pigweeds on the edge of a wheat field.PHOTO: DENNIS LANGE, MANITOBA AGRICULTURE Date: October 17, 2023 Kilometres MoreWATERHEMP on page 1210SEED MANITOBA 2024SEEDMB.CA SEEDMB.CASEED MANITOBA 2024 11'