Permethrin
PESTICIDE NAME: Permethrin
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Trade name(s): Ambush, Pounce
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Manufacturer(s): FMC Corp.
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Ag.Chem Group
200 Market St.
Philadelphia, PA. 19103
ICI Americas, Inc.
Ag. Chem. Div.
Wilmington, DE. 19897
I. Basic information
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A. Molecular structure: C21H20Cl203
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B. Chemical name: [(3-phenoxyphenyl methyl)-cis,trans-_3-2,2-
dichloroethenyl-2,2-dimethylcyclopropanecarboxylate]
C. Derivatives: dichlorovinyl acid and 3 phenoxybenzyl alcohol
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moieties (from hydrolysis); cis-permethrin and trans-permethrin
D. Molecular weight: 391.3 g/mole
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E. Solubility in water: <1 mg/l
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F. Common physical appearance: colorless crystals to viscous
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liquid; water white to pale yellow
G. Oral LD50(rat): >4000 mg/kg
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H. Pesticide classification: synthetic pyrethroid insecticide
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I. Restricted use list (N.Y.): yes
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EPA priority pesticide list: no
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J. Crop use: apple, pear, peach, cabbage, cauliflower, broccoli,
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Brussels sprouts, lettuce, endive, escarole, potato, sweet corn
II. Text
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Permethrin is a readily degraded synthetic pyrethroid insecticide
which is stable in air and light. It has a half-life of approximately
28d in mineral soil and persists longer in organic soils. The
cis-isomer of permethrin has been found to be more resistant to
degradation than the trans-isomer. Permethrin is not subject to
downward movement in soil and has been extensively treated in the
scientific literature. Its use in New York is widespread on both fruit
and vegetable crops.
III. Soils information
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A. Degradation and transformation
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Permethrin is readily degraded in most soils except organic; its
half-life ranges from 3 to 6wks(5,7,10). In organic soils, permethrin
was found to persist for 28d then decrease slowly during the
season(6). At harvest, permethrin concentration has been found to be
65% of applied in organic soils(8). There is slower degradation of
permethrin in sterile than in non-sterile soils. In sterile mineral
soil, 8wks after initial application, the permethrin equaled 100% of
the applied; in non-sterile mineral soil, residues totaled 6% of
applied; in sterile organic soil the remainder was 100% and in
non-sterile organic soil 16% of the applied permethrin remained(3). In
silty clay loam, the permethrin concentration increased in one study
during theapplication period due to wash from the plant leaves (July
1976), but the pesticide disappeared between Jan. and March of
1977(1).
Several factors influence loss rate of permethrin from soil.
Degradation is slowed or stopped completely with addition of Na-azide,
steam sterilization or under anoxic conditions(7). In a well-oxidized
soil, permethrin is gone in 19d at all pH levels; however, under
reducing conditions, 33% of applied permethrin disappeared in 26d at
pH5 but 66% was gone in the same amount of time at pH8. From this it
was concluded that permethrin could persist in sediments(4). Added
nutrients may increase the degradation of permethrin(7); however,
application of permethrin has been shown to have decreased the
availability of N and P in soils(8).
The tables below present data concerning permethrin degradation in
soils. The reference is given in parentheses at the end of each title.
Concentration of permethrin isomers in silt loam and clay loam soils
under sterile and non-sterile conditions(10)
weeks cis-permethrin trans-permethrin
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(sterile) (non-ster) (sterile) (non-ster)
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silt 0 0.38 ppm 0.37ppm 0.56ppm 0.60ppm
loam 2 0.30 0.18 0.54 0.19
4 0.22 0.09 0.44 0.10
6 0.28 0.09 0.50 0.07
clay 0 0.42 0.42 0.65 0.64
loam 2 0.32 0.37 0.62 0.47
4 0.30 0.17 0.49 0.14
6 0.36 0.12 0.64 0.11
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Persistence of permethrin (% initial application) in soil under surface
and incorporated application methods(2)
INCORP. Time Sand Muck SURFACE Sand Muck
_______ ____ ____ ____ _______ ____ ____
0.5 43 88 58 88
1 14 39 15 66
2 <14 7 <8 29
3 16 44
4 11 34
5 5 34
6 1 . Can.Entomol.
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113(8). 685-94.
6.Kahn, S.U. 1980. Pesticides in the Soil Environment.
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Amsterdam:Elsevier.
*7.Lord, K.A., M. McKinley and N. Walker. 1982. Environ. Poll. Ser.A.
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29. 81-90.
8.Mathur, S.P., A. Belanger, H.A. Hamilton and S.U. Kahn. 1980.
Pedobiologia. 20(4). 237-42.
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9.Sharom, M.S. and K.R. Solomon. 1981. J.Agric.FoodChem. 29. 1122-25.
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*10.Williams, I.H. and M.J. Brown. 1979. J.Agric.FoodChem. 27(1).
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130-32.
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site is not a substitute for a pesticide label. Trade names used herein
are for convenience only; no endorsement of products is intended, nor is
criticism of unnamed products implied. Most of this information is historical
in nature and may no longer be applicable.
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