TEBUCONAZOLE

Common name: Tebuconazole

Chemical name: α-[2-(4-chlorophenyl)ethyl]-α-(1,1-dimethylethyl)-1 H -1,2,4-triazole-1-ethanol

Structural formula:

Chemical class: Azole fungicide

CAS No.: 107534-96-3

Properties: Technical product is off-white crystalline powder. M.p. 105 ℃ . V.p. 1.7 × 10 -3 mPa (20 ℃ ). Soluble in water 36mg/L (pH 5-9, 20 ℃ ). In dichloromethane ﹥ 200, isopropanol, toluene 50-100, hexane ﹤ 0.1 (all in g/L, 20 ℃ ). Stable to elevated temperatures, and to photolysis and hydrolysis in pure water, under sterile conditions; hydrolysis DT 50 ﹥ 1 y (pH 4-9, 22 ℃ ).

Toxicity: Acute oral LD 50 for male rats 4000, female rats 1700, mice c. 3000 mg/kg. Acute percutaneous LD 50 for rats ﹥ 5000 mg/kg. Non-irritating to skin, mild irritant to eyes (rabbits). Inhalational LC 50 (4 h) for rats 0.37 mg/L air (aerosol), ﹥ 5.1 mg/L (dust).

Ecotoxicology: Birds, acute oral LD 50 for male Japanese quail 4438, female Japanese quail 2912, bobwhite quail 1988 mg/kg. Fish, LC 50 (96 h) for rainbow trout 6.4, golden orfe 8.7 mg/L. Bees, non-toxic to bees. Worms, acute (14 d) for Eisenia foetida 1.381 mg/kg dry soil. Daphnia LC 50 (48 h) 11.5 mg/L.  

Environmental fate: Animals, after three days, elimination was almost complete ( ﹥ 99%). Tebuconazole was excreted with the urine and the faeces. Plants, metabolism studies on wheat, grape and peanut show that tebuconazole is the major terminal residue. The metabolites detected were mainly triazole-containing compounds of no toxicological relevance. In plant tissue, a mean half-life of 12 days could be derived (cereals). Soil/Environment, the degradation of tebuconazole in soil was slow in laboratory studies. Under field conditions, the compound degraded much more rapidly, and did not accumulate in long-term studies (3-5 y). Since no residues could be detected in deeper soil layers of these and other studies, and adsorption/desorption studies indicated a low mobility in the soil, groundwater contamination through leaching can be excluded. In natural waters, hydrolysis and indirect photolysis occur; in a pond study, the compound dissipated from the water body with DT 50 1-3 w. Low vapour pressure and strong adsorption result in low volatilization into the air.

Treatment: Symptomatic treatment.

Mode of action: Systemic fungicide with protective, curative, and eradicant action. Rapidly absorbed into the vegetative parts of the plant, with translocation principally acropetally.

Usage: As a seed dressing, tebuconazole is effective against various smut and bunt diseases of cereals such as Tilletia spp., Ustilago spp., and Urocystis spp., also against Septoria nodorum (seed-borne), and Sphacelotheca reiliana in maize. As spray, tecuconazole controls numerous pathogens in various crops: rust species ( Puccinia spp.), powdery mildew ( Erysiphe graminis ), Rhynchosporium secalis , Septoria spp., Pyrenophora spp., Cochliobolus sativus and Fusarium spp. in cereals; Mycosphaerella spp. Puccinia spp. and Sclerotium rolfsii in peanuts; Mycosphaerella spp. in bananas; Sclerotinia sclerotiorum and various pathogens of leaf and stem diseases in oilseed rape; Exobasidium vexans in tea; Phakopsora pachyrhizi in soya beans; Monilinia spp., rust species, powdery mildewand scab in pome and stone fruit; Botrytis spp., rust species, powdery mildew fungi, and (with dipping or spraying) Sclerotium cepivorum in grapes and some vegetable crops.