IDENTIFICATION
Common name: Myclobutanil
Other name: myclobutanil (BSI, ANSI, draft E-ISO, (m) draft F-ISO)
Iupac name: 2-p-chlorophenyl-2-(1 H-1,2,4-triazol-l-ylmethyl)hexanenitrile; 2-(4-chlorophenyl)-2-(1 H-1,2,4-triazoN -ylmethyl) hexanenitrile
Chemical abstracts name: α-butyl-α-(4-chlorophenyl)-l H-1,2,4-triazole-1 -propanenitrile
Type: Fungicide
CAS RN: [88671-89-0]
M.F.: C15H17ClN4
Mol Wt: 288.8
PHYSICAL CHEMISTRY
Form (appearance): Pale yellow solid.
M.P.: 63-68℃ (tech.)
B.P.: 202-208℃/1 mmHg
V.P.: 0.213 mpa (25℃)
Solubility.: In water 142 mg/l (25℃). Soluble in common organic solvents, e.g. ketones, esters, alcohols and aromatic hydrocarbons, all 50-100 g/l. Insoluble in aliphatic hydrocarbons.
Stability: Stable under normal storage conditions. Aqueous solutions decompose on exposure to light, DT50 222 d (sterile water), 0.8 d (sensitized sterile water), 25 d (pond water); no hydrolysis (28℃) in 28 d (pH 5, 7, and 9).
Henry: 4.33 × 10-4 Pa m3 mol-1 (calc.)
KowlogP: 2.94 (pH 7-8, 25℃)
APPLICATION
Formulation types: EC; SC; WP; Seed treatment.
Biochemistry: Inhibits ergosterol biosynthesis (steroid demethylation inhibitor).
Mode of action: Systemic fungicide with protective and curative action.
Uses: Control of Asc0rnycetes, Fungi Imperfecti, and Basidiomycetes on a wide variety of crops. For example, used as a fo1iar treatment for control of scab and powdery mildew in apples and pears; powdery mildew, shot-hole, blossom blight, and rust in stone fruit; powdery mildew in vines and cucurbits; powdery mildew and rusts on ornamentals; rusts on perennial grasses grown for seed; and various diseases of wheat; as a seed treatment for control of seed- and soil-borne diseases in barley, maize, cotton, rice and wheat; and as a post-harvest drench or dip.
MAMMALIAN TOXICOLOGY
Reviews: AO/WHO 65, 67 (see part 2 of the Bibliography).
Oral: Acute oral LD50 for male rats 1600, female rats 2290 mg/kg.
Skin and eye: Acute percutaneous LD50 for rabbits >5000 mg/kg. Not irritating to their skin but mildly to their eyes; not a skin sensitiser to guinea pigs.
Noel: (90 d) for rats and female dogs 100, male dogs 10 mg/kg diet. No reproductive effects were observed in rats at 200 mg/kg, but there were some reproductive effects in male rats at 1000 mg/kg.
ADI: (JMPR) 0.03 mg/kg b.w. [1992].
Other Non-teratogenic in rats and rabbits, and various mutagenicity tests proved negative. Not mutagenic in the Ames assay.
Toxicity: WHO (a.i.) III EC hazard R631 Xn; R221 Xl; R361 N; R51, R53
ECOTOXICOLOGY
Birds: Acute oral LD50 for bobwhite quail 510, grey partridges 1635 mg/kg.
Fish: LC50 (96 h) for bluegill sunfish 2,4, rainbow trout 4.2 mg/l.
Daphnia: LC50 (48 h) 11 mg/l.
Worms: Bees Non-toxic to bees.
ENVIRONMENTAL FATE
Plant: In plants, metabolism is the same as in animals.
Animals: In animals, undergoes oxidation at the butyl group to a ketone and an alcohol, with partial conjugation to a glucoside. Following oral administration, rapidly excreted in the faeces and urine.
Soil/Environment: In soil, DT50 66 d (silt loam). Decomposition is through highly polar triazole compounds, with further degradation by ring splitting. No degradation under anaerobic conditions.
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