Pyribenzoxim

Favorites

Chemical Identification | General Product Information | Physical & Safety Data

Chemical Identification

Common Name

Pyribenzoxim

中文通用名

嘧啶肟草醚

IUPAC

benzophenone O-[2,6-bis(4,6-dimethoxypyrimidin-2-yloxy)benzoyl]oxime

CAS

diphenylmethanone O-[2,6-bis[(4,6-dimethoxy-2-pyrimidinyl)oxy]benzoyl]oxime

CAS No.

168088-61-7

Molecular Formula

C₃₂H₂₇N₅O₈

Molecular Structure

General Product Information

Category

Herbicides > Unclassified herbicides

Activity

Herbicide.Pyribenzoxim is a non-competetive inhibitor of ALS and the observed ALS inhibition data for rice and barnyard grass is similar suggesting that the basis for selectivity does not lie at the biochemical site of action. Transient chlorosis has been observed in crops 3-5 days after application but this is rapidly outgrown; it is proposed that the observed crop selectivity is due to rapid metabolism of pyribenzoxim in rice.

Pyribenzoxim has a broad-spectrum of tolerance in grass crops with the exception of maize. It has a wide window of application in rice and controls barnyard grass from the 2 leaf to tillering stage. In field trials, the herbicide has been shown to be safe to both direct-seeded and transplanted rice and also to turf species including Kentucky bluegrass, bentgrass, zoysiagrass and perennial ryegrass.

The product is suitable for mixing with post-emergent ALS inhibitor herbicides and pre-emergence amide, carbamate and dinitroaniline herbicides. Antagonism has been observed in mixtures with certain post-emergence products. Trials in Korea have demonstrated that propanil decreases the whole plant activity of pyribenzoxim in Echinochloa crus-galli by reducing translocation to adjacent tissues. Propanil was applied at 0.5 to 4 kg ai/ha from 1 day before to 5 days post-pyribenzoxim treatment. The extent of translocation of radiolabelled pyribenzoxim out of the leaf was reduced from 11% of the total absorbed 48 hours after treatment with pyribenzoxim alone to 3.5% when propanil was applied to the same leaf. Translocation of radiolabel increased to 15% when propanil was applied to an adjacent leaf. The studies found that translocation within 5 days of treatment is required for pyribenzoxim activity as plants were not completely controlled when the treated leaf was removed before that period. Foliar absorption of pyribenzoxim was not affected by propanil.

CropUse

CropUses:
barley, rice, turf, wheat

30-50 g ai/ha

Premix

Quinclorac+Pyribenzoxim+Pyrazosulfuron-ethyl
Pyribenzoxim+Pyrazosulfuron-ethyl+Cyhalofop-butyl
Pyribenzoxim+Pretilachlor+Cyhalofop-butyl
Pyribenzoxim+pretilachlor
Pyribenzoxim+cyhalofop-butyl
Penoxsulam+Pyribenzoxim
Penoxsulam+Cyhalofop-butyl+Pyribenzoxim
Cyhalofop-butyl+Pyribenzoxim+Bentazone

Physical & Safety Data

Physical Properties

Molecular weight:609.6; Physical form:White, odourless solid. Melting point:128-130 °C; Vapour pressure:9.9 ×10-1 mPa; Partition coefficient(n-octanol and water):logP = 3.04; Solubility:In water 3.5 ppm (25 °C).;

Toxicology

Oral:Acute oral LD₅₀ for rats and mice >5000 mg/ kg. Percutaneous:Acute percutaneous LD₅₀ for rats >2000 mg/kg. Not an eye irritant, nor a skin sensitiser.

Environmental Profile

Ecotoxicology:
Algae: EC₅₀ (96 h) for algae >100 mg/l.Bees: LD₅₀ (24 h) for honeybees >100 mg/l.Daphnia: LC₅₀ (48 h) >100 mg/l.

Environmental fate:
Soil:Relatively immobile and rapidly degraded in soil. In leaching tests using either sandy loam or silty clay soil, in artificial soil columns, >90% of pyribenzoxim accumulated in the 0-10 cm zone. WATER SOLUBILITY: 3.5 ppm at 25°C

Transport Information

Hazard Class:O (Obsolete as pesticide, not classified)