Kresoxim-methyl

Description

Kresoxim-methyl is a strobilurin fungicide. It inhibits conidial germination of V. inaequalis isolates from apple orchards (EC₅₀s = 0.00033-0.0078 mg/L). Kresoxim-methyl also inhibits mycelial growth (EC₅₀ = 0.240 mg/L) and is fungicidal against Saprolegnia (MIC = 1 mg/L). It increases intracellular calcium levels and disrupts the mitochondrial membrane potential in mouse cortical cultures in a concentration-dependent manner. Kresoxim-methyl is toxic to goldfish (C. auratus; LC₅₀ = 0.807 mg/L).

The Uses of Kresoxim-methyl

Kresoxim-methyl is used for the control of several diseases (scab, mildews, blast, sheath blight and others) on a range of crops including apples, pears, vines, sugar beet and cereals.

The Uses of Kresoxim-methyl

An agricultural fungicide.

The Uses of Kresoxim-methyl

Agricultural fungicide.

What are the applications of Application

Kresoxim-methyl is a reagent also known as benzeneacetic acid methyl ester

Definition

ChEBI: A carboxylic ester that is the methyl ester of (2E)-(methoxyimino){2-[(2-methylphenoxy)methyl]phenyl}acetic acid. A fungicide for the control of scab on apples and pears and other fungal diseases on a wide range of crops.

Hazard

Moderately toxic by skin contact. Low tox-icity by ingestion and inhalation.

Safety Profile

Moderately toxic by skin contact. Low toxicity by ingestion and inhalation. Questionable carcinogen with experimental data reported. When heated to decomposition it emits toxic vapors of NOx.

Metabolic pathway

By hepatocyte suspensions prepared from goats, pigs, hens, and rats that have been cryopreserved and thawed, BAS 490 F is metabolized via the same pathways as observed using fresh rat hepatocytes. The rate of hydrolysis of 14C-BAS 490 F leading to a carboxylic acid derivative seems to be constant between the cryopreserved and fresh hepatocytes except for goats. The oxidation reaction at the methyl group of the phenoxy ring, leading to the hydroxymethyl analog of the carboxylic acid of BAS 490 F, significantly decreases after cryopreservation, whereas the formation of (E)-2-methoxyimino-2[2-(4- hydroxy-2-methylphenyloxymethyl)phenyl] acetic acid by hydroxylation at the 4-position of the phenoxy ring remains at a constant rate. In pig hepatocytes, the two hydroxylated metabolites of the phenoxy ring, carboxy BAS 409 F and (E)-2-methoxyimino-2-o- hydroxymethylphenyl acetic acid, are formed to a lesser extent after cryopreservation.

Metabolism

Kresoxim-methyl is rapidly metabolized in mammalian systems to the virtually inactive carboxylic acid, accounting for its low toxicity and high level of selectivity. Atharvest residues in cereals and top fruit are <0.05 mg/kg and <1 mg/kg in grapes and vegetables. The soil DT₅₀ = <3 days, and the Koc is 219 to 372. For the main metabolite, the Koc is 17 to 24. Hydrolytic stability tests indicate a DT₅₀ of 34 days at pH 7 but only 7 h at pH 9.

Degradation

Kresoxim-methyl is a stable crystalline solid with limited water solubility. It is stable in the pH range 3-8 but it is hydrolysed to the carboxylic acid (2, see Scheme 1) in base. DT₅₀ values (25 °C) at pH 5,7 and 9 were 875,34 and 0.29 days, respectively. The product (2) was stable under these conditions.
Kresoxim-methyl undergoes rapid photodegradation in water when irradiated with UV light. Its DT₅₀ was 3 days and several products were formed, one of which was the Z-isomer. Details of the other products are not available. Under conditions of simulated sunlight the compound was degraded with a DT₅₀ of 37 days in pure water and 19 days in natural pond water.

Toxicity evaluation

Kresoxim-methyl has an acute oral LD₅₀ > 5,000 and an acute dermal LD₅₀ > 2,000 mg/kg in rats. The NOEL for rats is 800 ppm, and the ADI = 0.4 mg/kg bw (body weight). Kresoxim-methyl is not a skin or eye irritant, is nonmutagenic and nonteratogenic. It shows toxicity to aquatic organisms (fish 96-h LC50 = 0.681 to 1 mg/L) but does not cause permanent damage. Other nontarget organisms show the following levels of sensitivity: bird: 14-day LD₅₀ = 2,150 mg/kg; bee: 48- h LD₅₀ ≥ 20 μg/bee; worm: LC50 ≥ 937 mg/kg; Daphnia: 48-h EC50 = 0.186 mg/L; and algae 0- to 2-h EC50 = 63 μg/L.