Herbicide Properties

Y2000 prices for Brand Name Target Weed some trade Herbicide Examples Chemical Name Herbicide Family Sps. Mode of Action products Navigate®, Class®, Weed-Pro®, ® 2,4 D Justice (2,4-dichlorophenoxy) acetic acid phenoxy broadleaf weeds Auxin mimic $35/gal WeedHo annual and ® Reclaim , Curtail®, 3,6-dichloro-2-pyridinecarboxylic perennial Clopyralid Transline® acid pryridine broadleaf weeds Auxin mimic $358/gal Transline

(R)-2-[4-[[5-(trifluoromethyl)-2- Inhibits acetyl-CoA Fusilade DX®, pyridinyl]oxy]phenoxy]propanoic arylozyphenoxy- annual and carboxylase prohibitng ® Fluazifop-p-Butyl Fusion®, Tornado acid propionate perennial grasses fatty acid synthesis $65/qt Fusilade

ethyl hydrogen (aminocarbonyl) none generally ® Fosamine Krenite phosphonate recognized trees and bushes Mitotic inhibitor $55/gal Krenite Inhibits the shikimac $141 for 2 1/2 gal RoundUp®, Rodeo®, none generally annual and acid pathway depleting RoundUp; $80/qt Glyphosate Accord® N-(phosphonomethyl)glycine recognized perennial weeds aromatic amino acids Rodeo

3-cyclohexyl-6-(dimethylamino)-1- methyl-1,3,5-triazine-2,4(1H,3H)- annual, biennials, $83/gal Velpar; ® ® Hexazinone Velpar , Pronone dione triazine perennial Blocks Photosystem II $469/lb Pronone (±)-2-[4,5-dihydro-4-methyl-4-(1- Inhibits AHAS ® methylethyl)-5-oxo-1H-imidazol-2- Plateau , Plateau yl]-5-methyl-3-pyridinecarboxylic annual and synthesis, blocking $308/gal Plateau; ® Imazapic Eco-Pak®, Cadre acid imidazolinone perennialannual weedsand amino acid synthesis $72/Eco-Pak (+)-2-[4,5-dihydro-4-methyl-4-(1- perennial grasses, Inhibits acetolactate methylethyl)-5-oxo-1H-imidazol-2- broadleafs, vines, synthase blocking ® Imazapyr Arsenal yl]-3-pyridinecarboxylic acid imidazolidinone brambles,annual andbrush, amino acid synthesis $358/gal Arsenal perennial $43/gal Tordon 4-amino-3,5,6-trichloro-2- broadleaf weeds, 101; $107/gal ® Picloram TordonK pyridinecarboxylic acid pryridine vines, and woody Auxin mimic Tordon K

2-[1-(ethoxyimino)butyl]-5-[2- (ethylthio)propyl]-3-hydroxy-2- annual and ® Sethoxydim Poast cyclohexen-1-one cyclohexanedione perennial grasses Lipid synthesis inhibitor $204/gal Poast $295 for 2 1/2 gal [(3,5,6-trichloro-2- woody and annual Garlon; $155/gal ® ® Triclopyr Garlon , Remedy pyridinyl)oxy]acetic acid pryridine broadleaf weeds Auxin mimic Remedy

Weed Control Methods Handbook, The Nature Conservancy, Tu et al. Behavior in Soils Behavior in Water Mobility (based on Helling's classification system - Helling & Turner Average Half-life in Herbicide Average Soil Half-life Soil Sorption (Koc) 1968) Water Solubility Water 900 mg/L (acid), 100 20 mL/g (acid/salt), 100 mg/L (ester), 796,000 varies from hours to 2,4 D 10 days mL/g (ester) moderate-high mg/L (salt) months

avg 6 mL/g but ranges 1,000 mg/L (acid), Clopyralid 40 days to 60 mL/g moderate-high 300,000 mg/L (salt) 8-40 days

Fluazifop-p-Butyl 15 days 5,700 mL/g moderate* 1.1 mg/L stable in water

Fosamine 8 days 150 mL/g moderate* 1,790,000 mg/L stable in water 15,700 mg/L (acid), 900,000 mg/L (IPA Glyphosate 47 days 24,000 mL/g low salt), 4,300,000 mg/L 12 days to 10 weeks

several days to > 9 Hexazinone 90 days poor, Koc unk. moderate-high 33,000 mg/L months

Imazapic 120-140 days 206 mL/g low? 36,000 mg/L (pH 7) < 8 hours

Imazapyr 25-141 days poor, Koc unk. low-moderate 11,272 mg/L 2 days

16 mg/L (can range -17- 430 mg/L (acid), Picloram 90 days 160 mL/g) moderate-high 200,000 (salts) 2-3 days

257 mg/L (pH 5), 4,390 Sethoxydim 5 days 100 mL/g high* mg/L (pH 7) hours in sunlight 430 mg/L (acid), 23 20 mL/g (salt), 780 mg/L (ester), 2,100,000 Triclopyr 30 days mL/g (ester) moderate-high mg/L (salt) 4 days *unofficial estimate Degradation Mechanism Toxicity & [EPA Toxicity Categories*]

LD50 - Birds Microbial Solar Oral LD50 - (BW - bobwhite LC50 - Fish Dermal LD50 - Herbicide Degradation Chemical Degradation Mammals (Rats) quail, M - mallards) (bluegill sunfish) Rabbit

Primary 764 mg/kg 500 mg/kg (BW) 263 mg/L 2,4 D mechanism Minor mechanism Low potential [low] [moderate] [moderate] NA

Primary 4,300 mg/kg 1,465 mg/kg (M) 125 mg/L Clopyralid mechanism Minor mechanism Low potential [low] [low] [moderate] >2000 mg/kg >3,528 mg/kg Primary Secondary 4,096 mg/kg (M) 0.53 mg/L Fluazifop-p-Butyl mechanism mechanism Low potential [low] [low] [high] >2420 mg/kg 10,000 mg/kg Primary Very minor 24,000 mg/kg (BW/M) 670 mg/L Fosamine mechanism mechanism Very low potential [slight] [slight] [low] >1683 mg/kg > 4,640 mg/kg Primary 5,600 mg/kg (BW/M) 120 mg/L Glyphosate mechanism Minor mechanism Low potential [slight] [low] [moderate] >5000 mg/kg 2,258 mg/kg Primary Moderate 1,690 mg/kg (BW) 370 mg/L Hexazinone mechanism Minor mechanism potential [low] [low] [moderate] >6000 mg/kg > 2,150 mg/kg Primary Very minor > 5,000 mg/kg (BW) > 100 mg/L Imazapic mechanism mechanism? Low? [slight] [low] [moderate] > 5000 mg/kg > 2,150 mg/kg Primary Moderate > 5,000 mg/kg (BW/M) >100 mg/L Imazapyr mechanism Minor mechanism potential [slight] [low] [moderate] >2000 mg/kg > 2,510 mg/kg Primary Primary Moderate > 5,000 mg/kg (M) >14.4 mg/L Picloram mechanism mechanism potential [slight] [low] [high] >2000 mg/kg > 2,510 mg/kg Primary >2,676 mg/kg (M) 100 mg/L Sethoxydim mechanism Minor mechanism High potential [low] [low] [moderate] >5000 mg/kg

Primary Moderate 713 mg/kg 1,698 mg/kg (M) 148 mg/L Triclopyr mechanism Minor mechanism potential [low] [low] [moderate] >2000 mg/kg *based on EPA Toxicity Categories Herbicide Notes Inexpensive and common herbicide used for over 50 2,4 D years. Highly selective herbicide developed as an alternative to Clopyralid picloram. Toxic to most grasses except annual bluegrass and all fine Fluazifop-p-Butyl fescues.

Not registered for use in Fosamine California or Arizona. Little to no soil activity. Some formulations are highly toxic to Glyphosate aquatic organisms.

Potential for ground water Hexazinone contamination. Toxic to algae.

Degree of control depends on Imazapic selectivity of individual plants.

Provides long-term total Imazapyr vegetation control. Environmental persistence can endanger non-target plants and Picloram animals.

Rapid degradation can limit Sethoxydim effectiveness. Commonly used herbicide. The ester formulation is highly toxic Triclopyr to aquatic organisms.

Date Authored: April 2001