Trade and Other Names: Trade names for products containing fluazifop-p-butyl include Fluazifop-p-butyl ester, Fusilade 2000, Fusilade DX, Fusilade Five, Fusilade Super, Fusion, Horizon, Ornamec, PP005, and Tornado.
Regulatory Status: Fluazifop-p-butyl is a slightly to practically nontoxic compound in EPA toxicity class IV [1,2]. It is a General Use Pesticide (GUP), and labels for products containing it must bear the Signal Word CAUTION.
NOTE: This profile is for fluazifop-p-butyl herbicide, which is a different compound than either fluazifop-p or fluazifop butyl. Fluazifop-p-butyl is the n-butyl ester of the acid Fluazifop-p. Fluazifop-p is the R-enantiomer ("dextro" or "plus") of the acid, while Fluazifop typically contains equal proportions of both the R- and S-enantiomers [2,3]. Fluazifop-p (the R-enantiomer) is the herbicidally active portion of the mixture.
Introduction: Fluazifop-p-butyl is a selective postemergence phenoxy herbicide used for control of most annual and perennial grass weeds in cotton, soybeans, stone fruits, asparagus, coffee, and others. It may often be used with an oil adjuvant or nonionic surfactant to increase efficiency. It has essentially no activity on broadleaf species. It is compatible with a wide variety of other herbicides and may also be found in formulations with other products such as fenoxaprop ethyl ester (in Horizon and Fusion) and fomesafen (in Tornado). It is available as an emulsifiable concentrate. Fluazifop-p-butyl formulations may contain some fluazifop-butyl.
Formulation: It is available as an emusifiable concentrate. Fluazifop-p-butyl formulations may contain some fluazifop-butyl.
Acute toxicity: Fluazifop-p-butyl is slightly to practically nontoxic via the oral route. The reported acute oral LD50 values for technical fluazifop-p-butyl are 3680  to 4096 mg/kg  in male rats, and 2451 to 2721 mg/kg  in female rats. The reported acute oral LD50 values for one formulated product (Fusilade DX) are higher, indicating practically no toxicity via the oral route . A single large oral dose of a formulated compound (Fusilade 2000) can cause severe stomach and intestine disturbance . Ingestion of large quantities may also cause problems in the central nervous system such as drowsiness, dizziness, loss of coordination, and fatigue . Fluazifop-p-butyl is slightly toxic via the dermal route as well. The reported dermal LD50 for the compound is greater than 2400 mg/kg in rabbits [5,6]. It is reported to cause only slight skin and mild eye irritation in rabbits, but no skin sensitization in guinea pigs [5,6]. The formulation Fusilade DX is reported to have similar acute toxicity via the dermal route, and does not cause skin sensitization in guinea pigs, but may cause moderate skin and mild eye irritation in rabbits . The formulation Fusilade DX is reported to have an 4-hour inhalation LC50 of greater than 0.54 mg/L in male rats and 0.77 mg/L in female rats, indicating moderate toxicity via the inhalation route . Breathing small amounts of the product Fusilade 2000 may cause vomiting and severe lung congestion; larger amounts may ultimately lead to labored breathing, coma, and death .
Chronic toxicity: Rats fed small amounts of fluazifop-p-butyl for 90 days developed no compound-induced effects at doses at or below 10 mg/kg/day .
Mutagenic effects: Numerous tests have shown the compound to be nonmutagenic .
Organ toxicity: Organ toxicity has not been seen in experimental animals .
Effects on birds: Fluazifop-p-butyl is practically nontoxic to bird species; the reported acute oral LD50 for the technical product in mallards is greater than 3528 mg/kg [5,6]. The reported 5-day dietary LC50 in mallard duck is greater than 4321 ppm, and in bobwhite quail is greater than 4659 ppm .
Effects on aquatic organisms: Fluazifop-p-butyl may be highly to moderately toxic to fish, but only slightly toxic to other aquatic species, such as invertebrates. The reported 96-hour LC50 values for the technical product in fish species are 0.53 mg/L in bluegill sunfish and 1.37 mg/L in rainbow trout , indicating very high to high toxicity. The 48-hour LC50 in Daphnia magna (an aquatic invertebrate) is reported as greater than 10 mg/L , indicating only slight toxicity.
Effects on other organisms: The compound is of low toxicity to bees. Oral and contact LD50 values for bees are greater than 0.20 mg/bee .
Breakdown in soil and groundwater: Fluazifop-p-butyl is of low persistence in moist soil environments, with a reported half-life in these conditions of less than 1 week [5,6]. Fluazifop-p-butyl breaks down rapidly in moist soils to the fluazifop acid, which is also of low persistence. Fluazifop-p-butyl and fluazifop-p are both reported to be of low mobility in soils and not to present appreciable risks for groundwater contamination . The reported soil adsorption coefficient for fluazifop-p indicates a moderate to low affinity for soil .
Breakdown in water: Fluazifop-p-butyl is rapidly hydrolized (cleaved apart by water) under most conditions to the fluazifop acid [2,3]. It is relatively stable to breakdown by UV or sunlight, and nonvolatile [5,6].
Breakdown in vegetation: After uptake by the leaves of plants, Fluazifop-p-butyl is rapidly broken down in the presence of water to fluazifop-p, which is translocated throughout the plant [5,6]. The compound accumulates in the actively growing regions of the plant (meristems of roots and shoots, root rhizomes and stolons of grass), where it interferes with energy (ATP) production and cell metabolism in susceptible species [5,6].
Appearance: The compound is a pale, straw-colored liqud .