Commonly Used Herbicides Rangeland & Non-crop Exploring Herbicides Used to Control Invasive Weeds

2,4-D - Many Trade Names Auxin-like, systemic, selective Auxin-like, systemic, selective Ester, amine, and acid formulationsEster, amine, and acid formulations Short residual in soil Short residual in soil average half-life 10 daysaverage half-life 10 days Broadleaf herbicide Broadleaf herbicide many annual broadleaf weedsmany annual broadleaf weeds  notably weak on kochia often tank-mixedoften tank-mixed High volatility High volatility

Dicamba - Vanquish/Clarity/Overdrive Auxin-like, systemic, selective Auxin-like, systemic, selective Relatively short soil residual Relatively short soil residual < 14 days good conditions metabolism< 14 days good conditions metabolism low to medium leaching potential, weakly adsorbedlow to medium leaching potential, weakly adsorbed Broadleaf herbicide Broadleaf herbicide many annuals, biennials, perennialsmany annuals, biennials, perennials  thistles and knapweeds  weak on toadflaxes & Russian knapweed Don’t use near water or trees/shrubs Don’t use near water or trees/shrubs buffalograss sensitive to injurybuffalograss sensitive to injury

Picloram - Tordon 22K, Grazon P+D Auxin-like, systemic, selective Auxin-like, systemic, selective Restricted use herbicideRestricted use herbicide Residual herbicide Residual herbicide average half-life 90 daysaverage half-life 90 days high leach potential, weakly adsorbedhigh leach potential, weakly adsorbed Broadleaf herbicide Broadleaf herbicide thistles, knapweeds, leafy spurge, houndstongue, toadflaxes, bindweed, locoweed, larkspur, lupines …thistles, knapweeds, leafy spurge, houndstongue, toadflaxes, bindweed, locoweed, larkspur, lupines …  Grazon P+D is picloram + 2,4-D very weak kochia & some mustardsvery weak kochia & some mustards Don’t use near water, trees/shrubs Don’t use near water, trees/shrubs smoothbrome sensitive to injurysmoothbrome sensitive to injury

Clopyralid - Stinger, Transline, Curtail Auxin-like, systemic, selective Auxin-like, systemic, selective Short residual Short residual average half-life 40 daysaverage half-life 40 days moderate leaching, weakly adsorbedmoderate leaching, weakly adsorbed Broadleaf herbicide - odd spectrum Broadleaf herbicide - odd spectrum thistles, knapweeds, hawkweeds, oxeye daisy, dandelion, locoweeds …thistles, knapweeds, hawkweeds, oxeye daisy, dandelion, locoweeds …  Above weeds, only control after emergence Don’t use around water Don’t use around water Safe around trees/shrubsSafe around trees/shrubs

Aminopyralid Milestone, Milestone VM, Forefront R&P Auxin-like, systemic, selective Auxin-like, systemic, selective Short residual Short residual average half-life 34.5 days in North Americaaverage half-life 34.5 days in North America Lab studies show potential movement; limited movement in fieldLab studies show potential movement; limited movement in field Broadleaf herbicide - odd spectrum Broadleaf herbicide - odd spectrum thistles, knapweeds, hawkweeds, oxeye daisy, dandelion, absinth wormwood …thistles, knapweeds, hawkweeds, oxeye daisy, dandelion, absinth wormwood …  Forefront R&P is aminopyralid + 2,4-D Can spray to water’s edge Can spray to water’s edge Half-life in water 0.6 daysHalf-life in water 0.6 days Safe around some trees/shrubsSafe around some trees/shrubs

Metsulfuron - Escort/Ally/Cimarron Amino acid biosynthesis inhibitor Amino acid biosynthesis inhibitor systemic, selectivesystemic, selective Moderate residual Moderate residual typical half-life 30 daystypical half-life 30 days  persistence increases with soil pH Broadleaf herbicide Broadleaf herbicide perennial mustards, biennial thistles, arrowgrass, locoweed, halogeton, houndstongue, camelthorn, African rue …perennial mustards, biennial thistles, arrowgrass, locoweed, halogeton, houndstongue, camelthorn, African rue …  Combined with Milestone = Capstone oExcellent on Russian knapweed + whitetop infestations (whitetop timing) weak on toadflaxes, Canada thistle, diffuse knapweedweak on toadflaxes, Canada thistle, diffuse knapweed must use a surfactant!!must use a surfactant!!

Chlorsulfuron - Telar Amino acid biosynthesis inhibitor Amino acid biosynthesis inhibitor systemic, selectivesystemic, selective Residual Residual average half-life 40 daysaverage half-life 40 days  persistence increases with soil pH Broadleaf herbicide Broadleaf herbicide perennial mustards, Russian knapweed, Canada thistleperennial mustards, Russian knapweed, Canada thistle  RK, CT high rates and fall best must use surfactant!!must use surfactant!! Fall applications more injurious to some grass speciesFall applications more injurious to some grass species

Imazapic - Plateau Amino acid biosynthesis inhibitor Amino acid biosynthesis inhibitor systemic, selectivesystemic, selective Residual Residual most “imis” persistentmost “imis” persistent  e.g. imazapyr 1-4 months Broadleaf and grass Broadleaf and grass leafy spurge, bindweed, houndstongue, cheatgrass, foxtail barley …leafy spurge, bindweed, houndstongue, cheatgrass, foxtail barley … must use methylated seed oil!!must use methylated seed oil!! Cool-season grass injury Cool-season grass injury fall applications for leafy spurgefall applications for leafy spurge

Glyphosate - Roundup, Campaign, Rodeo, Aquamaster Amino acid biosynthesis inhibitor Amino acid biosynthesis inhibitor systemic, non-selectivesystemic, non-selective  Rodeo is aquatic formulation Moderate persistence Moderate persistence average half-life 47 daysaverage half-life 47 days strongly adsorbed, no soil activitystrongly adsorbed, no soil activity Broadleaf and grass Broadleaf and grass many annuals, biennials, perennialsmany annuals, biennials, perennials CheatgrassCheatgrass  Glyphosate + Plateau (6 fl oz of each) oTreat late fall thru winter; weather dependent

Aminocyclopyrachlor Perspective Perspective Perspective Telar + aminocylopyrachlorTelar + aminocylopyrachlor Non-crop onlyNon-crop only Amino-acid biosynthesis inhibitor + Auxin- like; systemic, selective Amino-acid biosynthesis inhibitor + Auxin- like; systemic, selective Short to long residual Short to long residual Aminocylcopyrachlor half-life range days in North AmericaAminocylcopyrachlor half-life range days in North America Lab studies show potential movement; limited movement in fieldLab studies show potential movement; limited movement in field Broadleaf herbicide - odd spectrum Broadleaf herbicide - odd spectrum thistles, knapweeds, leafy spurge, mustards (Telar) …thistles, knapweeds, leafy spurge, mustards (Telar) …