Diclosulam

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Chemical Identification | General Product Information | Physical & Safety Data

Chemical Identification

Common Name

Diclosulam

中文通用名

双氯磺草胺

IUPAC

N-(2,6-dichlorophenyl)-5-ethoxy-7-fluoro-[1,2,4]triazolo[1,5-c]pyrimidine-2-sulfonamide

CAS

N-(2,6-dichlorophenyl)-5-ethoxy-7-fluoro-[1,2,4]triazolo[1,5-c]pyrimidine-2-sulfonamide

CAS No.

145701-21-9

Molecular Formula

C₁₃H₁₀Cl₂FN₅O₃S

Molecular Structure

General Product Information

Category

Herbicides > Triazolopyrimidine herbicides
Herbicides > Amide herbicides

Activity

Herbicide.
Diclosulam is effective against a range of important broadleaf weeds in soybean crops including morningglories, cocklebur, eclipta, velvetleaf and nutsedge, and also controls important weeds in the major peanut-growing areas of the US. It does not control sicklepod.

Diclosulam offers peanut growers greater flexibility by allowing pre-emergence control of weeds previously controlled only by post-emergence treatments. In most cases, it will not remove the need for post-emergence applications but it is expected to reduce the number by 1-2. Currently, growers may make up to 4 post-em treatments per season.

Strongarm can be applied preplant to the surface or incorporated into the top 1 - 3 inches of soil, not more than four weeks before planting. It can also be applied from premergence through to cracking in peanuts. For best results, Dow recommends that the fields should be clean-tilled and weed-free, the product should be applied as close as possible to planting, and 0.25 - 0.5 inches of water should be applied immediately if irrigation is available. For post-emergence control in peanuts, diclosulam should be applied when weeds are at the 1 - 4 leaf stage. In tillage systems, Dow suggest that Strongarm may be tank mixed with a burndown herbicide such as Gramoxone Max to control existing weeds.

Dow recommends a tank mixture of diclosulam and Syngenta's Dual (metolachlor) for the control of heavy infestations of nutsedge. For broad spectrum weed control a tank mix with a graminicide such as Sonalan HFP (ethalfuralin) is recommended. Diclosulam is also found to be more effective when applied in combination with Frontier, Outlook or Prowl. Application of Cadre (imazapic) with Strongarm should be avoided as it could limit crop rotation flexibility. This product also allows greater flexibility in crop rotation: planting of wheat, barley can be made 4 months after a peanut crop treated with Strongarm; similarly cotton can be planted 10 months after use of the product compared to 18-26 months for traditional broad leaf herbicides.

Experiments were conducted in North Carolina to evaluate weed management systems (in strip- and conventional-tillage peanut) consisting of different combinations of pre-emergence herbicides (including diclosulam) plus commercial post-emergence herbicide systems. Dimethenamid plus diclosulam applied pre was found to be more effective than dimethenamid alone, regardless of the post herbicide. The combination provided effective control (> 91%) of Chenopodium album, Eclipta spp and Sida spinosa. Diclosulam provided variable control of three Ipomoea species (59 - 91%), and only diclosulam systems controlled late season yellow nutsedge. The weed control of eight weeds, peanut yields or net returns were the same for both tillage systems.

CropUse

Crop uses:?
cotton, peanuts, soybeans

Peanuts	21 - 32 g ai/ha
Soybeans	32 - 42 g ai/ha

Physical & Safety Data

Physical Properties

Molecular weight:406.2; Physical form:Off-white solid. Brown granule; non-distinct odor. Density:1.602 (20 °C); Melting point:218-221 °C; Vapour pressure:6.67×10-10 mPa (25 °C); Partition coefficient(n-octanol and water):logP = 0.85 ( pH 7); pKa:4.0 (20 °C); Solubility:In water 6.32 μg/ml (20 °C). In acetone 0.797, acetonitrile 0.459, dichloromethane 0.217, ethyl acetate 0.145, methanol 0.0813, octanol 0.00442, toluene 0.00588 (all in g/100 ml, 20 °C).

Toxicology

Oral:Acute oral LD₅₀ for rats >5000 mg/ kg. Percutaneous:Acute percutaneous LD₅₀ for rats >2000 mg/kg. Not a skin sensitiser. Inhalation: LC₅₀ (4 h) for rats >5.04 mg/l. ADI:( JMPR) 0.01 mg/ kg b.w. [1998].

Environmental Profile

Ecotoxicology:?
Algae: EC₅₀ (14 d) for green algae (Selenastrum capricornutum) 1.6, bluegreen algae (Anabaena flos-aquae) 83 μg/l; NOEC for green algae 1.6, bluegreen algae 561 μg/l.Bees: LD₅₀ (48 h, contact) for honeybees >25 mg/bee.Birds:Acute oral LD₅₀ for bobwhite quail >2250 mg/kg. Acute dietary LC₅₀ for bobwhite quail and mallard ducks >5620 ppm.Daphnia: LC₅₀ (48 h) 72 mg/l; life-cycle NOEC 5.66 mg/l; LOEC 9.16 mg/l.Fish: LC₅₀ (96 h) for rainbow trout >110, bluegill sunfish >137, sheepshead minnow >120 mg/l.Worms: LC₅₀ (14 d) for earthworms >991 mg/ kg.Other aquatic spp.: LC₅₀ (96 h) for grass shrimp >120, Eastern oyster >120 mg/l. EC₅₀ for Lemna sp. 1.16 μg/l.Other beneficial spp.:Classed as practically non-toxic to slightly toxic. Environmental fate:?
Animals:Metabolised primarily by dealkylation of the ethoxy group and hydrolysis of the sulfonamide linkage.Soil:Dissipation of diclosulam occurs primarily through microbial degradation and is minimally influenced by soil pH. Soil DT₅₀ (in a wide variety of soils) c. 33-65 d. K_oc 55.?
WATER SOLUBILITY: Dispersible.

Bobwhite quail	LD₅₀ >2,250 mg/kg
Bluegill sunfish _{[96 h]}	LC₅₀ >137 mg/L
Rainbow trout _{[96 h]}	LC₅₀ >110 mg/L
Bee _[contact]	LD₅₀ >25 mg/bee

Fate in soil:
Diclosulam is degraded microbially in the soil. The half-life is between 22 and 42 days. The soil photolysis half-life is 41 days. The mean K_oc value is 78 ml/g.

Fate in aquatic systems:
The product is not appreciably degraded by hydrolysis at pH 5 or 7. At pH 9 the hydrolysis half-life of diclosulam is 2 days. The half-life in aqueous photolysis studies is 119 days (pH 5).

Transport Information

Signal Word:CAUTION; Hazard Class:III (Slightly hazardous).