E X T O X N E T
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
Publication Date: 5/94
TRADE OR OTHER NAMES
Trade names for the older compound fenvalerate included Ectrin,
Sanmarton, Sumifly, Sumiflower, Sumitick and Pydrin. The trade name for
the new product, esfenvalerate, is Asana XL. The compound may also be
listed as S-fenvalerate.
Most products containing esfenvalerate are General Use Pesticides
(GUP). The emulsified concentrate formulation is a Restricted Use
Pesticide (RUP) because of possible adverse effects to aquatic organisms.
Esfenvalerate has replaced the compound fenvalerate for use in the
United States. Much of the data for esfenvalerate is closely applicable to
the pesticide fenvalerate because the two compounds contain the same
components. The only difference in the two products is the relative
proportions of the four separate constituents (isomers). Esfenvalerate has
become the principal compound of the two because it results in lower
application rates than fenvalerate, is less chronically toxic, and is a
more powerful insecticide. The compound contains a much higher percentage
of the one insecticidally active isomer (84% for esfenvalerate and 22% for
Esfenvalerate is a synthetic pyrethroid insecticide which is used on a
wide range of pests such as moths, flies, beetles, and other insects. It
is used on vegetable crops, tree fruits, and nut crops. It may be mixed
with a wide variety of other types of pesticides such as carbamate
compounds or organophosphates.
Because esfenvalerate is a relatively new compound it has little usage
history. Esfenvalerate is a moderately toxic pesticide and carries the
signal word WARNING on the label. Because the two compounds, fenvalerate
and esfenvalerate, are made up of the same four constituents (though, in
different concentrations) some of the information gained from fenvalerate
is applicable here. The bulk of evidence related to acute poisonings in
humans due to fenvalerate comes from incidents in India, where nearly 600
cases of poisoning were reported between 1982 and 1988. These cases were
due to improper handling of the pesticide. Acute toxic effects were
observed in workers and among the general public. Symptoms of acute
poisoning included dizziness, stimulation and itching of the skin from
contact (which was worsened by sweating and washing). Severe cases of
direct contact caused blurred vision, tightness in the chest, and
convulsions. The symptoms appear to be reversible (6).
In rats, acute exposure to esfenvalerate produced muscle
incoordination, tremors, convulsions, nerve damage and weight loss. The
compound may produce nausea, vomiting, headache, temporary nervous system
effects such as weakness, tremors and incoordination in domestic animals if
accidentally ingested. Esfenvalerate is a strong eye irritant, producing
tearing or blurring of vision (9).
The oral LD50 of esfenvalerate is 458 mg/kg in rats. The dermal LD50
is 2000 mg/kg for rabbits, indicating that esfenvalerate is moderately
toxic by skin contact. The inhalation LC50 is greater than 2.93 mg/l for
Rats and mice fed fenvalerate at concentrations from 0 to 50 mg/kg/day
for two years had no compound-related effects except for significant
reduction in body weight in rats (13, 14).
In a three-generation rat study, low doses (up to 12.5 mg/kg) of
fenvalerate produced no toxicity in offspring. Some maternal toxicity was
noted in the second generation at the higher dose. There are no specific
data available for esfenvalerate, but it is not expected to cause
reproductive effects at low doses based on its similarity to esfenvalerate
Fenvalerate doses up to 50 mg/kg/day did not produce any birth defects
in fetuses when administered to pregnant rabbits on gestation days 6
through 18 and to mice on gestation days 6 through 15. Some maternal
toxicity occurred in both rabbits and mice during these studies. It
appears that the pesticide would not pose a serious threat to humans at low
exposure levels (11, 12).
Esfenvalerate has no mutagenic effects. Numerous tests in hamsters,
mice and rats show no signs of mutagenic activity associated with this
compound (9). It is unlikely that it poses mutagenic risk to humans.
Rats fed fenvalerate at doses up to 50 mg/kg/day for two years did not
develop cancer (13). Another two year rat study conducted over a wide
range of doses up to 75 mg/kg resulted in no evidence of cancer (15).
Mice which were fed diets containing small amounts of fenvalerate for
two years did not show a significant increase in effects, including cancer
(3). It appears that fenvalerate does not cause cancer. Based on the
similarity of esfenvalerate to fenvalerate it is not expected to cause
There is no mention of any dose related effects on internal organs of
test animals or in human populations in any of the references used for this
profile. Externally, contact with the compound may produce a tingling,
Fate in Humans and Animals
When cows were treated with 0.1 g or 0.5 g of fenvalerate on their
skin 0.03% to 0.06% of the applied chemical was found in their milk. When
the cows received 5 and 15 mg/l of fenvalerate orally in their rations, the
concentrations of fenvalerate in the whole milk increased to a maximum of
0.000048 mg/l and 0.000250 mg/l, respectively. Residues declined to non-
detectable levels by day 7 and day 10, respectively. The total secretion of
fenvalerate in the milk amounted to very little, 0.44% and 0.64%, of the
total dose fed in the diet (2).
Fenvalerate does not appear to be metabolized by the bovine rumen, but
is degraded further down the digestive tract. This happens rapidly since
less than 0.02% of the parent compound is found in the urine. In addition,
the major fenvalerate metabolite, 4-chloro-alpha-(1-methyl ethyl)-benzene
acetic acid was not detected in urine. It was estimated that 25% of the
parent compound was excreted in the feces (5).
While the data presented here are for fenvalerate, esfenvalerate
behaves in a similar manner (10).
Effects on Birds
Esfenvalerate is moderately toxic to birds. Acute oral LD50 value for
mallard ducks is 9,932 mg/kg. Dietary LC50 values for the technical
material, fenvalerate, are >10,000 ppm in bobwhite quail and 5,500 ppm in
mallard ducks (7).
Effects on Aquatic Organisms
Fish are very sensitive to esfenvalerate with 96-hour LC50s of 0.00026
mg/l for bluegill, 0.00026 mg/l for rainbow trout, 0.00134 mg/l for carp,
and 0.0019 mg/l for killifish. Daphnia magna, an aquatic invertebrate, has
an LC50 of 0.00024 mg/l. The pesticide is very highly toxic to these
species. These values are based on laboratory tests with the technical
material. Water turbidity, such as would be found in the field, tends to
reduce the toxicity of this compound (9).
Bioaccumulation factors in rainbow trout are about 400 times the
background (ambient water concentration of the pesticide) levels (7).
Effects on Other Organisms (Nontarget species)
Esfenvalerate is also highly toxic to bees. The compound tends to
repel bees for a day or two after application, causing bee visitations to
drop during that time (4). Since most intoxicated bees die in the field
before they can return to contaminate the hive, the brood is not exposed
except by direct spray. Dried spray residues are not expected to pose a
significant threat to bees (9).
Breakdown of Chemical in Soil and Groundwater
Under field conditions, fenvalerate has a half-life ranging from about
15 days to 3 months depending on soil type. In a soil laboratory study,
soil maintained under aerobic conditions have a half-life ranging from 65
days to 8 months, and soil maintained under anaerobic conditions have a
half-life of approximately 6 months (7).
Esfenvalerate and its breakdown products are relatively immobile in
soil and thus pose little risk to groundwater (7). The compound's ability
to bind to soil increases with increasing organic matter. It is very
insoluble in water. Fenvalerate has not been found in groundwater at over
100 groundwater supply sites (8).
Breakdown of Chemical in Surface Water
Esfenvalerate will hydrolyze and photodegrade in water. The half-life
of fenvalerate in natural water has been reported to range from 4 to 15
Breakdown in Plants
No information was available about the breakdown of this compound in
PHYSICAL PROPERTIES AND GUIDELINES
Esfenvalerate is a colorless, crystalline compound with a molecular
mass of 419.9 g/mol. The technical material is amber colored. Formulations
include emulsifiable concentrates, suspension concentrates, and ULV liquid.
|CAS #: ||66230-04-4 (1)
|Chemical name: ||(s)-cyano(3-phenoxy phenyl)methyl (s)-4-chloro-alpha-(1-methyl ethyl)benzene acetate
|Solubility in water: ||< 0.02 mg/l @ 20 degrees C (calculated)
|Solubility in other solvents: ||hexane 77 g/l; acetone, chloroform, methanol > 450 g/l @ 20 degrees C
|Melting Point: ||clear viscous liquid at 23 degrees C
|Vapor Pressure: ||0.067 mPa @ 25 degrees C
|Partition Coefficient (octanol/water) (log): ||6.22
|Adsorption Coefficient: ||5248
|Chemical class/use: ||synthetic pyrethroid insecticide
Du Pont Agricultural Products
Walker's Mill, Barley Mill Plaza
P.O. Box 80038
Wilmington, DE 19880-0038
Toll free: (800) 441-7515
Emergency: (800) 441-3637
Review by Basic Manufacturer:
Comments solicited: April, 1993
Comments received: May, 1993
The Agrochemicals Handbook: Third Edition. (1991). The Royal
Society of Chemistry, Unwin Brothers Ltd., Surrey, England.
Frank, R., H.E. Braun, L.A. Miller, and G.W. Allan. (1984).
Fenvalerate Residues in Milk Following Topical Treatments to Dairy Cows.
Pesticide Science, 15: 600-604.
Food and Agriculture Organization of the United Nations. (1981).
Pesticide Residues in Food - 1981. FAO Plant Production and Protection
Shell Chemical Company. (1982). Pydrin Insecticide. Technical Manual
Wszolek, P.C., N.A. LaFaunce, T. Wachs, and D.J. Lisk. (1981).
Studies of Possible Bovine Urinary Excretion and Rumen Decomposition of
Fenvalerate Insecticide and a Metabolite. Bulletin of Environmental
Contamination and Toxicology, 26: 262-266.
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Casarett and Doull's Toxicology, The Basic Science of Poisons: Fourth
Edition. Curtis D. Klaassen, Mary O. Amdur, and John Doull, Editors.
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Matthew N. Lorber. (1988). Pesticides in Ground Water Data Base; 1988
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Asana XL Technical Bulletin. (no date). Du Pont Chemical Corp.
O'Neal, Frederick O. (1991). Summary of Toxicological Studies
Supporting Safety Assessment of Du Pont "Asana" XL Insecticide. Du Pont
Report Number ESFE/GEN 1. Du Pont Chemical Corp.
Shell Chemical Company. (1975). Teratogenic study of fenvalerate with
rabbits. Unpublished study, MRID No. 00071664.
Shell Chemical Company. (1976). Teratogenic study of fenvalerate with
mice. Unpublished study, MRID No. 00064329.
Shell Chemical Company. (1978a). Oncogenicity study of fenvalerate
with rats over a two-year period. Unpublished study, MRID Nos. 00082007,
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with mice over a two-year period. Unpublished study, MRID No. 00079876.
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