Chemical Identification
Common Name
sodium 2-chloro-6-(4,6-dimethoxypyrimidin-2-ylthio)benzoate
sodium 2-chloro-6-[(4,6-dimethoxy-2-pyrimidinyl)thio]benzoate
Molecular Formula
Molecular Structure
Herbicide.Pyrithiobac-sodium is primarily a post-emergence herbicide though it can be used from pre- to post-emergence since the compound exhibits residual activity. It is taken up rapidly by roots and shoots and has greatest activity when applied at the 1-3 leaf stage of the weeds. Death occurs 10-14 days after application. Activity is enhanced by the addition of adjuvants such as: non-ionic surfactants; silicon-type adjuvants; and crop oil concentrates. Tank mixes with bromoxynil and/or glyphosate have extended pyrithiobac sodium's weed control spectrum and it is suitable for use on cotton genetically modified to be tolerant to these herbicides. Pyrithiobac has, however, been shown to be antagonistic to some other herbicides in tank mixes. FMC recommends that pyrithiobac-sodium is applied with clomazone pre-emergence, or early post-emergence following clomazone.

When applied post-emergence, pyrithiobac-sodium does not damage the cotton crop at the recommended use rate. Some chlorosis and stunting has been observed, but the quality and yield of cotton is not affected. It is safe to rotational crops. Early-season insecticides can be applied in mixtures or in sequence with pyrithiobac-sodium without crop injury, although some weakening of the cotton fibre has been observed. In field trials, pyrithiobac-sodium gave better control of weeds than commercial standards at lower application rates.


35 g ai/ha (pre-emergence)


70 g ai/ha (post-emergence)

Physical Properties
Molecular weight:348.7; Physical form:White solid. Density:1.609; Composition:Tech. is >93%. Melting point:233.8-234.2 °C ( decomp.); Vapour pressure:4.80 × 10-6 mPa (25 °C); Partition coefficient(n-octanol and water):logP = 0.6 ( pH 5), -0.84 ( pH 7); pKa:2.34; Solubility:In water 264 ( pH 5), 705 ( pH 7), 690 ( pH 9), 728 (unbuffered) (all in g/l, 20 °C). In acetone 812, methanol 270 × 103, n-hexane 10, dichloromethane 8.38 (all in mg<; Stability:Stable in water (32 d, pH 5-9, 27 °C) and to heat (15 d at 54 °C).
Oral:Acute oral LD50 for male rats 3300, female rats 3200 mg/ kg. Percutaneous:Acute percutaneous LD50 for rabbits >2000 mg/kg. Non-irritating to skin; irritating to eyes (rabbits). Inhalation: LC50 (4 h) for rats >6.9 mg/l. Phytotoxicity:Non-phytotoxic to cotton when applied as directed. ADI:( JMPR) 0.1 mg/ kg b.w. [1999].
Environmental Profile
Algae: EC50 (5 d) for Selenastrum capricornutum 107µg/l; NOEC for S. capricornutum 22.8 mg/l.Bees: LD50 (48 h, contact) >25µg/bee.Birds:Acute oral LD50 for bobwhite quail >2250 mg/ kg b.w. Dietary LC50 (5 d) for mallard ducks and bobwhite quail >5620 mg/ kg50 (48 h) >1100 mg/l.Fish: LC50 (96 h) for bluegill sunfish >930, rainbow trout >1000, sheepshead minnow >145 mg/l. 

Environmental fate: 
Animals:More than 90% of radiolabelled pyrithiobac, applied orally and intravenously at 5 mg/ kg to rats, was excreted in urine and faeces within 48 h; the major excreted metabolite was the O-desmethyl derivative. PyrithiSoil:Microbial and photochemical degradation play a major role in degradation in the environment; DT50 in silty soil 60 d. Kd 0.32 (sandy loam), 0.60, 0.38, 0.75 (3 silty loam soils).Plant:Amounts of pyrithiobac-sodium in cotton leaves rapidly decreased, following foliar application; at 62 dat, no residues were found; major metabolites found in foliage were the phenol formed by mono-demethylation, and its glucose conjugate. WATER SOLUBILITY: Soluble, 1% wt/wt (pH 5.6)
Fate in soil:
Pyrithiobac-sodium is degraded primarily by soil microbes. It has a soil half-life of approximately 60 days.

Fate in aquatic systems:
Pyrithiobac-sodium is degraded photochemically in water.

Transport Information
Signal Word:WARNING; Hazard Class:II(Moderately hazardous)

Porduct NewsMore

Colombia’s Constitutional Court bans chlorpyrifos


ADAMA Canada moves forward with lambda-cyhalothrin sales for 2023


Copper formulations' market still underestimated: Chinese self-developed Thiazoles is tapping potential of global market

Copper fungicides

Mexico: Import of glyphosate drops from 16,500 tons to 8,200 tons


Glyphosate to gain temporarily one year approval in EU without support of qualified majority of Member States


Glyphosate prices drop 30% in Argentina


One year extension of EU glyphosate approval failed to pass in the latest meeting


Palmer amaranth in two southern U.S. states now resistant to S-metolachlor


FMC introduces Altacor EVO insect control, new management solution for lepidopteran pests


Paraquat prices rise, pyridine base industry analysis


Related CompaniesMore

Dhanuka Agritech Ltd.

Country:  India

Oxyfluorfen Kasugamycin Carfentrazone-ethyl Bispyribac-sodium Pyrithiobac-sodium Quizalofop-P-ethyl Halosulfuron-methyl Carbendazim+mancozeb Tricyclazole Flusilazole Flusilazole+Carbendazim Iprovalicarb+propineb Propineb Difenoconazole+Propiconazole Isoprothiolane Kasugamycin+copper oxychloride Azoxystrobin+difenoconazole Azoxystrobin+Tebuconazole Propargite Cartap hydrochloride Bifenthrin Carbosulfan Emamectin benzoate Acetamiprid Buprofezin Spinosad Chlorantraniliprole Chlorantraniliprole Spiromesifen Imidacloprid Flubendiamide Cyflumetofen Pyriproxyfen Cartap hydrochloride Pendimethalin Pendimethalin Imazethapyr Clodinafop-propargyl Paraquat dichloride Chlorimuron-ethyl 2,4-D dimethyl amine salt Butachlor Copper oxychloride Carbendazim Copper hydroxide Hexaconazole Kasugamycin Carbendazim+mancozeb Carboxin+thiram Carboxin+thiram Propiconazole Imidacloprid Cartap hydrochloride Cartap hydrochloride Sulfoxaflor Fipronil Lambda-cyhalothrin Lambda-cyhalothrin Quinalphos Phenthoate Chlorpyrifos Dinotefuran Fipronil Fipronil Triazophos Monocrotophos Cypermethrin Cypermethrin Chlorantraniliprole Lambda-cyhalothrin Diafenthiuron Chlorpyrifos+cypermethrin

Shenzhen Baocheng Chemical Industry CO.,LTD.

Country:  China

Glyphosate Emamectin benzoate Lambda-cyhalothrin Pyraclostrobin Bromacil Glufosinate-ammonium Tembotrione Prothioconazole Topramezone Chlorantraniliprole

Jiangsu Agrochem Laboratory Co., Ltd.

Country:  China

Florasulam Cloransulam-methyl Mesosulfuron-methyl Triflusulfuron-methyl Iodosulfuron-methyl Imazamox Halosulfuron Thidiazuron Flucarbazone-sodium Diclosulam

Jiangsu Repont Agrochemical Co., Ltd.

Country:  China

Chlorimuron-ethyl Bensulfuron-methyl Thifensulfuron-methyl Ethxosulfuron Flucarbazone Carfentrazone Florasulam Metribuzin Flumetsulam Flazasulfuron.

Hangzhou Tianlong Biotechnology Co., Ltd.

Country:  China