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in 1996. EXTOXNET no longer updates this information, but it may be useful
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E X T O X N E T
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EXTOXNET primary files maintained and archived at Oregon State
Revised June 1996
Trade and Other Names:
Trade names for the older fenvalerate compounds include Ectrin,
Pydrin, Sanmarton, Sumifly, Sumiflower, and Sumitick. Trade names
for the new product, esfenvalerate, include Asana XL, Halmark,
and Sumi-alfa. The compound may also be listed as S-fenvalerate.
Most products containing esfenvalerate are General Use Pesticides
(GUPs). The emulsified concentrate formulation is a Restricted
Use Pesticide (RUP) because of possible adverse effects in
aquatic organisms. Esfenvalerate is a moderately toxic pesticide
in EPA toxicity class II; products containing it must contain the
Signal Word WARNING on the label.
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 fruit, and nut
crops. It may be mixed with a wide variety of other types of
pesticides such as carbamate compounds or organophosphates.
Esfenvalerate has replaced the naturally occurring compound
fenvalerate (to which it is almost identical) for use in the U.S.
Much of the data for fenvalerate is applicable to the pesticide
esfenvalerate because the two compounds contain the same
components. The only differences in the two products are the
relative proportions of the four separate constituents (isomers).
Esfenvalerate has become the preferred compound because it
requires lower applications 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
Formulation: It may be
mixed with a wide variety of other types of pesticides such as
carbamate compounds or organophosphates. Esfenvalerate has
replaced the naturally occurring fenvalerate( to which it is
almost identical) for use in the U.S. Much of the data for
fenvalerate is applicable to the pesticide esfenvalerate because
the two compounds contain the same components. The only
differences in the two products are the relative proportions of
the four separate constituents (isomers). Esfenvalerate has
become the preferred compound because it requires lower
applications 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 fenvalerate).
- Acute toxicity: Esfenvalerate is a
moderately toxic compound via the oral route. The
reported oral LD50 of esfenvalerate is 458 mg/kg in rats.
It is slightly toxic via the dermal route, with a
reported dermal LD50 of 2500 mg/kg in rabbits. It is
practically non-toxic via inhalation, with a reported
inhalation LC50 of greater than 2.93 mg/L in rats [2,12].
Because esfenvalerate is a relatively new compound it has
little usage history. The bulk of evidence related to
acute poisonings in humans due to esfenvalerate comes
from incidents in India. Nearly 600 individual 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, burning and itching (which was worsened by
sweating and washing). Severe cases of direct contact
caused blurred vision, tightness in the chest, and
convulsions (2). The changes appear to be reversible. In
rats, high 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 at acute
exposure levels in humans. Esfenvalerate is a strong eye
irritant, producing tearing or blurring of vision.
- Chronic toxicity: Rats fed fenvalerate
at concentrations of approximately 12.5 mg/kg/day for two
years had no compound-related changes in the blood or
urine . In other studies significant reduction in
body weight was the main adverse effect seen in both rats
and mice of both sexes.
- Reproductive effects: In a
three-generation rat study, low doses (up to 12.5
mg/kg/day) of fenvalerate produced no toxicity in the
fetus. Some maternal toxicity was noted in the second
generation at the higher dose. When pregnant mice and
rabbits were fed low dietary levels of fenvalerate (2.5
mg/kg/day) on days 6 to 15 of gestation, there was
maternal toxicity in both species. It seems that during
pregnancy, the females are more sensitive to fenvalerate
than they would otherwise be, even though the toxicity is
not reflected in any effect on the fetus . There are
no specific data available for esfenvalerate, but it is
not expected to cause reproductive effects at low doses.
- Teratogenic effects: Esfenvalerate did
not produce any birth defects in offspring at low dietary
doses . It appears the the pesticide would not pose a
teratogenic threat to humans at expected exposure levels.
- Mutagenic effects: Esfenvalerate shows
no mutagenic effects. Numerous tests in hamsters, mice
and rats show no signs of mutagenic activity associated
with this compound . It is likely that it poses no
mutagenic risk to humans.
- Carcinogenic effects: A rat study of
fenvalerate conducted over a wide range of doses of up to
75 mg/kg, for two years, resulted in no evidence of
cancer. Mice fed diets containing small amounts of
fenvalerate for two years showed no adverse effects .
It appears that fenvalerate does not cause cancer.
- Organ toxicity: Studies to date have not
shown any dose-related effects on internal organs of test
animals or in human populations .
- Fate in humans and animals: Cows treated
with 0.1 or 0.5 g fenvalerate on their skin had 0.03 to
0.06% of the applied chemical in the milk. When the cows
received fenvalerate orally at very low levels, about
0.50% of the dose appeared in the milk. Fenvalerate does
not appear to be metabolized by bovine rumen, but it is
degraded further down the digestive tract . This
happens rapidly with less than 0.02% of the parent
compound found in the urine and 20% of the major
metabolite present. Higher concentrations of the parent
compound are present in the feces. In the rat,
fenvalerate is rapidly broken down and almost completely
eliminated within several days. One study indicated
mammals eliminated 96% in the feces in 6 to 14 days .
While the data presented here are for fenvalerate,
esfenvalerate behaves in the same manner .
- Effects on birds: Esfenvalerate is
slightly toxic to birds. Oral LD50 values for the
compound are 1312 mg/kg in bobwhite quail and greater
than 2250 mg/kg in mallard ducks .
- Effects on aquatic organisms: Based on
laboratory studies, fish are very sensitive to
esfenvalerate. It has a 96-hour LC50 of 0.0003 mg/L in
bluegill, 0.0003 mg/L in rainbow trout, 0.001 mg/L in
carp, and 0.0002 mg/L in killfish . The LC50 in
Daphnia magna, an aquatic invertebrate, is 0.001 mg/L.
The pesticide is very highly toxic to these species.
Water turbidity, such as would be found in the field,
tends to reduce the toxicity of this compound .
Bioaccumulation factors in rainbow trout are about 400
times the background (ambient water concentration of the
pesticide) levels .
- Effects on other organisms: Esenvalerate
is 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 . 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 .
- Breakdown in soil and groundwater: Under
field conditions, esfenvalerate is moderately persistent
with a half-life ranging from about 15 days to three
months depending on soil type . In a soil laboratory
study, 17% of the applied chemical was lost in 90 days.
Esfenvalerate and its breakdown products are relatively
immobile in soil and thus pose little risk to groundwater
. The compounds ability to bind to soil increases
with increasing organic matter. It is very insoluble in
water. Fenvalerate has not been found in over 100 tested
groundwater supplies .
- Breakdown in water: Esfenvalerate will
break down in water to one-half of the original amount
(half-life) in about twenty-one days due to sunlight
- Breakdown in vegetation: The parent
compound is the residue most often found on foliage. In a
series of trials in Canada where 16 varieties of fruits
and vegetables were grown under typical outdoor
conditions, no degradation products or metabolites were
found (tests were sensitive to 0.05 mg/kg). Sampling was
from 1 to 112 days after application. The half-life of
esfenvalerate on plant surfaces is 2 to 4 weeks .
- Appearance: The pure compound exists as
colorless crystals; the technical product as an amber
- Chemical Name:
- CAS Number: 66230-04-4
- Molecular Weight: 419.90
- Water Solubility: <0.3 mg/L at 25 C,
insoluble in water 
- Solubility in Other Solvents: v.s. in
hexane, acetone, chloroform, and methanol @ 20 C 
- Melting Point: 59-60 C 
- Vapor Pressure: 0.067 mPa @ 25 C 
- Partition Coefficient: 6.2201 
- Adsorption Coefficient: 5300 
- ADI: Not Available
- MCL: Not Available
- RfD: Not Available
- PEL: Not Available
- HA: Not Available
- TLV: Not Available
DuPont Agricultural Products
Walker's Mill, Barley Mill Plaza
P.O. Box 80038
Wlimington, DE 19880-0038
- Phone: 800-441-7515
- Emergency: 800-441-3637
References for the information in this PIP can be found in
Reference List Number 2
information in this profile does not in any way replace or
supersede the information on the pesticide product labeling or
other regulatory requirements. Please refer to the pesticide