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Extension Toxicology Network

A Pesticide Information Project of Cooperative Extension Offices of Cornell University, Michigan State University, Oregon State University, and University of California at Davis. Major support and funding was provided by the USDA/Extension Service/National Agricultural Pesticide Impact Assessment Program.


Publication Date: 9/93


Trade names for products containing quizalofop-p-ethyl are Assure II, Pilot Super, Targa D+ and Targa Super. The compound may be found in formulations with other herbicides such as benazolin and clopyralid (trade name Benazalox).


Quizalofop-P-ethyl is a selective, postemergence phenoxy herbicide. It is used to control annual and perennial grass weeds in potatoes, soybeans, sugar beets, peanuts vegetables, cotton and flax. The compound is absorbed from the leaf surface and is moved throughout the plant. It accumulates in the active growing regions of stems and roots. Quizalofop-P and quizalofop-p-ethyl should not to be confused with quizalofop or quizalofop ethyl. These latter two compounds are distinctly different than the former two. The material in this profile only refers to the compound quizalofop-p-ethyl unless specifically stated to the contrary. This is a relatively new compound and thus very little information is available about its toxicity or environmental characteristics. The compound is a General Use Pesticide.



Quizalofop-P-ethyl is a slightly toxic compound by oral exposure. End-use products require the signal word CAUTION be placed on their labels. The oral LD50 of the compound is 1,210 mg/kg in male rats and 1,182 mg/kg in female rats. Mice are only slightly less susceptible to the compound. Quizalofop-P-ethyl has an LD50 of 1,753 mg/kg in male mice and 1,805 mg/kg in female mice (1). No reports of sub-acute signs and symptoms were found. Exposure to the compound on the skin of rabbits indicated that the compound is only slightly toxic by this route as well. The acute percutaneous (absorbed through the skin) LC50 for quizalofop-p-ethyl in rabbits is greater than 2,000 mg/kg (1). No information about the compound toxicity through inhalation was available. Quizalofop-P-ethyl is non-irritating to the skin and only slightly irritating to the eyes in rabbits (1). It is non-sensitizing to the skin.


One short-term study (90 days) with rats produced no effects at the moderate dose level of 128 mg/kg. This appears to be the highest dose that has been tested for this compound in chronic feeding experiments.

Reproductive Effects

No information was found.

Mutagenic Effects

No information was found.

Carcinogenic Effects

No information was found.

Organ Toxicity

No information was found.

Fate in Animals and Humans

Quizalofop-P is rapidly broken down in mammals. More than 90% of a single oral dose is eliminated in urine within three days (1).


Tests with mallard ducks and bobwhite quail have shown that quizalofop-p-ethyl is practically non-toxic to these organisms. The compound has an eight day feeding (dietary) LC50 of greater than 5,000 mg/kg/day in both species. Quizalofop-P-ethyl is toxic to bees, with an LD50 of greater than 0.1 mg/kg (1). No information about the potential to accumulate in the tissues of organisms, mammals or aquatic species was found.


In sterilized soil (no microorganisms), the compound is very rapidly broken down. Half of the initial amount of the compound is lost under these conditions within one day. Soil microorganisms increase the rate at which the compound is broken down (1). No information about the potential of the compound to leach from soil or about its fate and behavior in aquatic systems was found.

Exposure Guidelines:

NOEL (rat): 128 mg/kg

Physical Properties:

Common name: quizalofop-p-ethyl
CAS #: 100646-51-3
Chemical Class: phenoxy, quinoxaline
Chemical Use: herbicide
Solubility in water: 0.4mg/l at 20 degrees C
Solubility in other solvents: 650 g/l in acetone, 22 g/l in ethanol, 5 g/l in hexane, 360 g/l in xylene. All at 20 degrees C
Melting point: 76-77 degrees C
Vapor pressure: 11 nPa at 20 degrees C


Nissan Chemical Industries Ltd.
Kowa-Hititsubashi Bldg. 7-1
3-Chome, Kanda-Nishiki-cho
Chiyoda-ku Tokyo Japan
Telephone 02-3296-8155
Telex: 222 3071 NISCTK J
FAX: 302-3296-8016

Review by Basic Manufacturer:

Comments solicited: June, 1993
Comments received:


  1. The Agrochemicals Handbook. 1991. The Royal Society of Chemistry. Cambridge, England.
  2. The Farm Chemicals Handbook. 1992. Meister Publishing. Willoughby, OH.