Spiroxamine

Spiroxamine

螺环菌胺

8-tert-butyl-1,4-dioxaspiro[4.5]decan-2-ylmethyl(ethyl)(propyl)amine

8-(1,1-dimethylethyl)-N-ethyl-N-propyl-1,4-dioxaspiro[4.5]decane-2-methanamine

118134-30-8

C₁₈H₃₅NO₂

Fungicides > Unclassified fungicides

Fungicide

Spiroxamine is particularly effective in the control of Erysiphe graminis on wheat and barley. The product blocks fungal sterol biosynthesis by inhibition of delta14 reductase, as opposed to the azole fungicides which act by blocking C14 demethylation. It acts preventatively by blocking the formation of the appressoria. When used as a curative treatment, the haustoria formed in the plant tissues are distorted. The product also destroys mycelia and conidia present on the surface of the plant. Spiroxamine penetrates the leaf and is translocated acropetally to the leaf tip. Bayer reports that the product shows even distribution throughout the leaf and does not accumulate in the leaf tip.

In field trials, the product has shown comparable activity to DMI's, morpholines, sulfur and piperidines. In cereals, the lower application rate is particularly suitable for higher growth stages; higher rates are required for good persistance of activity. In vines, Prosper and Hoggar should be applied at 14-day intervals, but not more than three times a season. The product has been shown not to affect either the fermentation or the organoleptic qualities of wines. On hops, a maximum of two applications can be made per season, at 28 day intervals, and at least 28 days pre-harvest.

Bayer states that no cross-resistance has been observed with strobilurins, quinolines, triazoles and piperidines. The company recommends its use in resistance management programmes.

CropUses:
barley, hops, oats, rye, vines, wheat

Cereals	500-800 g ai/ha
Vines	300-400 g ai/ha
Hops	18 oz/acre Accrue (1.3 l./ha)

Spiroxamine+Tebuconazole
Emulsifiable concentrate, emulsion, oil in water. Premix Parters: chlorsulfuron sulfometuron-methyl; cloransulam-methyl; 2,4-D dicamba mecoprop-P; 2,4-D dicamba quinclorac; metribuzin;

Type	AI concn
Emulsifiable concentrate (EC)	50% (w/v)
	80% (w/v)
Capsule Suspension (CS)	30.9% (w/v)

Molecular weight:297.5; Physical form:Faintly yellowish liquid; ( tech. is a light brown, oily liquid). Density:A and B both 0.930 (20 °C); Composition:Comprises 2 diastereoisomers, A and B, in the proportions 49-56% and 51-44%, respectively. Melting point:<-170 °C (separate diastereoisomers, spiroxamine A, spiroxamine B, and tech. mixture of both diastereoisomers); Flash point:147 °C; Vapour pressure:A: 9.7 mPa (20 °C); B: 17 mPa (25 °C) (both extrapolated); Henry constant:A: 2.5 × 10-3; B: 5.0 × 10-3 (both in Pa m3 mol-1, 20 °C, calc.); Partition coefficient(n-octanol and water):A: logP = 2.79; B: logP = 2.92 (unstated pH); pKa:6.9, base; Solubility:In water, mixture of A and B: >200 × 103 mg/l (pH 3, 20 °C); A: 470 ( pH 7), 14 ( pH 9); B: 340 ( pH 7), 10 ( pH 9) (both diastereoisome; Stability:Stable to hydrolysis and photodegradation; provisional photolytic DT50 50.5 d (25 °C).;

Oral:Acute oral LD₅₀ for male rats c. 595, female rats 500-560 mg/kg. Percutaneous:Acute percutaneous LD₅₀ for male rats >1600, female rats c. 1068 mg/kg b.w. Severe skin irritant; not an eye irritant (rabbits). Inhalation: LC₅₀ (4 h) for male rats c. 2772, female rats c. 1982 mg/m³. ADI:(US) 0.027 mg/kg b.w.; (Japan, Australia) 0.024 mg/kg b.w.

Ecotoxicology:
?Algae:E_rC50 (96 h) for Scenedesmus subspicatus 0.012, Pseudokirchneriella subcapitata 0.0194 mg/l.Bees:No risk to bees.Birds: LD₅₀ 565 mg/kg.Fish: LD₅₀ (96 h) for rainbow trout 18.5 mg/l.Worms: LC₅₀ ×1000 mg/kg dry wt. substrate.?

Environmental fate:?
Animals:Biokinetics and metabolism studies in rats showed a high degree of absorption of radioactivity followed by fast elimination from the body (>97 % within 48 h after oral administration). The radioactivity was readily distributed from the plSoil:Readily degraded in soil, ultimately to CO₂; oxidation on the t-butyl moiety and des-alkylation of the amine are the primary reaction steps. The des-alkylated compounds were either further oxidised to the corresponding acids or furtherPlant:Extensively metabolised in spring wheat and grapes, by oxidation, desalkylation and cleavage of the ketal structure; the resulting metabolites bearing a hydroxylated t-butyl group or an aminodiol were further conjugated. In the confined rotationa

Bobwhite quail	LD50 565 mg/kg
Rainbow trout	LC5011.5 mg/L
Earthworms	LC50 31,000mg/kg dry soil
Daphnia magna	EC50 5.1 mg ai/L
Green algae	EC50 0.0032 mg ai/L

Fate in soil:
The soil half-life of spiroxamine ranges from 35-64 days.

Fate in aquatic systems:
The half-life in supernatant water is between 12 and 13 hours.

Hazard Class:II(Moderately hazardous)