Trinexapac-ethyl

Trinexapac-ethyl

抗倒酯

ethyl (RS)-4-cyclopropyl(hydroxy)methylene-3,5-dioxocyclohexanecarboxylate

ethyl 4-(cyclopropylhydroxymethylene)-3,5-dioxocyclohexanecarboxylate

95266-40-3

C₁₃H₁₆O₅

Plant growth regulators > Unclassified plant growth regulators

Plant Growth Regulator

Trinexapac-ethyl is primarily for post-emergence use. The product is absorbed by the foliage and is translocated to the shoot meristem where it causes shortening of the internode length and strengthening of the upper internodes. It is most effective at reducing stem height when applied prior to flowering, but the anti-lodging effect is independent of application timing. The activity persists from application to harvesting in field crops and for several weeks in turf grass. One application of trinexapac-ethyl has been shown to reduce growth rate in turf by 40% for 4-6 weeks. Higher application rates are required for broadleaf crops. In ryegrass trinexapac-ethyl produces a three-fold improvement in lodging reduction and increases seed yield by up to 70%. Trials on spring oats showed a height reduction of 15% and yield benefits of 6%.

In field trials, no phytotoxicity was observed on cereals.

CropUses:
barley, oats, oilseed rape, rice, rye, sugar cane, triticale, turf, wheat

Cereals: 100-250 g ai/ha	Oilseed rape: 300-400 g ai/ha
Sugar cane: 125-250 g ai/ha	Turf: 100-420 g ai/ha (per application)

Type	AI concn
Emulsifiable concentrate (EC)	25% (w/v)
Micro-emulsion (ME)
Wettable powder (WP)
Soluble granule (SG)

Molecular weight:252.3; Physical form:White, odourless solid; (tech. is a yellow to red-brown liquid (30 °C) and a solid-liquid melt (20 °C), with a slight sweet odour). Density:1.215 g/cm3 (20 °C); Composition:Tech. is ×92% pure. Melting point:36 °C; Flash point:133 °C (1013 mbar) (EEC A9); Vapour pressure:1.6 mPa (20 °C); 2.16 mPa (25 °C) ( OECD 104); Henry constant:5.4 × 10-4 Pa m3 mol-1; Partition coefficient(n-octanol and water):logP = 1.60 ( pH 5.3, 25 °C); pKa:4.57; Solubility:In water 2.8 ( pH 4.9), 10.2 ( pH 5.5), 21.1 ( pH 8.2) (all in g/l, 25 °C). In ethanol, acetone, toluene, n-octanol 100%, n-hexane 5% (25 °C).; Stability:Heat-stable up to boiling point. Photolytically and hydrolytically stable under normal environmental conditions ( pH 6-7, 25 °C). Less stable in alkali.;

Oral:Acute oral LD₅₀ for rats 4460 mg/kg. Percutaneous:Acute percutaneous LD₅₀ for rats >4000 mg/kg. Not irritant to skin or eyes of rabbits. Non-sensitising to skin (guinea pigs). Inhalation:LC₅₀ (48 h) for rats >5.3 mg/l. Phytotoxicity:Could cause inhibition or growth stoppage of some plants, e.g. grasses, aquatic plants and algae.

Ecotoxicology:
Bees:Non-toxic; LD₅₀ (oral) >293 µg/bee; (contact) >115 µg/bee.Birds: LD₅₀ for ducks and quail >2000 mg/kg. LC₅₀ (8 d) for ducks and quail >5000 ppm.Daphnia: LC₅₀ (96 h) 142 mg/l.Fish: LC₅₀ (96 h) for trout, carp, bluegill sunfish, catfish, fathead minnow 35-180 mg/l.Worms:Low toxicity to earthworms; LC₅₀ >93 mg/kg. 

Environmental fate: 
Animals:In rats, goats and hens, 90% excretion occurs within 24 h, all as the acid metabolite.Soil:In soil, the ester undergoes rapid degradation, DT₅₀ <1 d. The acid has K_d values 1.5-16, K_oc 140-600. Further metabolism is rapid, DT₅₀ typicallPlant:Rapid metabolism to the acid, which remains by far the predominant metabolite.

Bobwhite quail [96 hrs]	LD50 >2,000 mg/kg Mallard duck LD50 >2,000 mg/kg
Rainbow trout [96 hrs]	LC50 68 mg/litre Bluegill sunfish [96 hrs] LC50 >130 mg/litre
Daphnia [48 hrs]	LD50 142 mg/litre

 

Signal Word:CAUTION; Hazard Class:III(Slightly hazardous)