Physical/Chemical Parameters:Fenvalerate
Fenvalerate
PESTICIDE NAME: Fenvalerate
___________
Trade name(s): Pydrin, Ectrin
_____________
Manufacturer(s): Shell Chemical Co., Division of Shell Oil
________________
P.O. Box 3871
Houston, TX. 77001
SDS Biotech Corp.
7528 Auburn Rd.
P.O. Box 348
Painesville, OH. 44077
I. Basic information
_________________
A. Molecular structure: C25H22ClNO3
___________________
B. Chemical name: cyano(3-phenoxyphenyl)methyl 4-chloro-
_____________
alpha(1-methylethyl)benzeneacetate
C. Derivatives: CONH2-Pydrin; 4-OH-Pydrin
___________
D. Molecular weight: 419.9 g/mole
________________
E. Solubility in water: very low solubility
___________________
F. Common physical appearance: clear, yellow, viscous liquid
__________________________
G. Oral LD50(rat): 451 mg/kg
______________
H. Pesticide classification: synthetic pyrethroid insecticide
________________________
I. Restricted use list (N.Y.): yes
__________________________
EPA priority pesticide list: no
___________________________
J. Crop use: apple, pear, peach, cabbage, cauliflower, broccoli,
Brussels sprouts, potato, sweet corn, tomato
II. Text
____
Fenvalerate is a non-leaching, non-volatile readily degradable
synthetic pyrethroid insecticide which is similar in behavior to
permethrin but remains in the soil for a longer time than permethrin.
It is used on a variety of fruits and vegetables in New York state and
is not on the restricted use list. The scientific literature contains
a moderate amount of information on fenvalerate in soils. The
half-life of fenvalerate varies from 6 weeks to 60 days depending upon
the soil type.
III. Soils information
_________________
A. Degradation and transformation
______________________________
The degradation of fenvalerate is slower in sterile than
non-sterile soil thus indicating the primary path of decomposition is
biological rather than chemical(2,5,7). Degradation is also affected
by treatment and moisture levels and rates are not constant over
time(1). Disappearance is more rapid in mineral than organic
soil(1,2). The percent fenvalerate left in mineral and organic sterile
and non-sterile soils 8wks after application has been reported as 91%
in mineral sterile soil, 12% in mineral non-sterile, 100% in organic
sterile, and 58% in organic non-sterile(2). A second study reported
losses of 78% of the applied fenvalerate in mineral non-sterile soil at
2wks and a loss of only 21% in organic non-sterile soil in 10wks(1).
From this it was concluded that multiple applications of fenvalerate on
a muck soil could result in accumulation of the pesticide.
The half-life of fenvalerate varies according to the soil being
tested. Values reported are 6wks in clay loam with 15.1% remaining
after 16wks and 11.3% remaining after 45wks(4); half-life of 2mo in
mineral and organic soils(1); half-life in aerobic sandy loam equal to
60d(5); loss of 50% of initial application at 9wks decreasing to 12% at
48wks and the fenvalerate at this point being a combination of 4
isomers (3); and half-life light clay = 2d, sandy clay loam = 6d and
sandy loam = 18d(6). This last study examined the relationship between
half-life of fenvalerate and latitude finding a fall/winter increase in
half-life where latitude >40deg N and no difference in spring/summer.
At latitudes <20deg N, half-lives remained constant at all times of the
year(6). Another researcher reports a rapid decrease in fenvalerate
applied to silt loam soil in the spring with a slowing of degradation
in the fall. This study also reported virtually no carry-over from
year to year and that more fenvalerate was recovered from cultivated
soils than from fallow soils(9). In a subtropical soil, the pesticide
was applied biweekly for 2yrs with no accumulation until 6mo after
initial application and 4% recovery at the end of 2yrs(10).
The reaction products of fenvalerate are CONH2-Pydrin and
4-OH-Pydrin with eventual decomposition to CO2. The reaction products
are not persistent in soil(7).
The tables below present data concerning degradation and
transformation of fenvalerate in soil. The reference is given in
parentheses at the end of each title.
Percent fenvalerate remaining in two soils under two cultivation
regimes(1)
Incorporated Fenvalerate Surface Fenvalerate(1)
_________________________ ______________________
Time(mo) Sand Muck Sand Muck
________ ____ ____ ____ ____
0.5 89% 100% 71% 53%
1 67 56 31 49
2 22 28 11 26
3 33 29 6 28
4 11 57 3 29
5 <11 25 <3 29
6 25 15
12 32
18 17
28 7
(values for top 1/3 of 15cm core)
***********************************************************************
Percent of original fenvalerate application remaining in soil under
different initial concentration and moisture regimes(1)
Percent application remaining in soil
__________________________________________________
Time (mo) 0.5ppm 10ppm
_________ ___________________________________________________
0.5%mois. 5%mois. 0.5%mois. 5%mois.
_________ ______ _________ _______
0.5 46 38 74 98
1 29 23 49 63
2 15 13 26 45
3 6 8 14 29
4 4 10 10 25
5 2 4 6 15
6 2 4 3 29
***********************************************************************
Degradation rate constants for fenvalerate under differing
concentration and moisture regimes(1)
Laboratory Experiments Rate a(mo-1)
___________________________________________________
Conc(ppm) Mois(%) Overall 0-1mo. 1-end
___________________________________________________
0.5 0.5 0.658 1.24 0.566
0.5 5.0 0.475 1.47 0.344
10.0 0.5 0.567 0.713 0.534
10.0 5.0 0.394 0.463 0.376
Field Experiments
_________________
Sand Incor. 0.529 0.410 0.499
Sand Surf. 0.897 1.18 0.760
Muck Incor. 0.075 0.580 0.106
Muck Surf. 0.229 0.720 0.158
***********************************************************************
Percent fenvalerate or specie in different soils under light or dark
conditions(6)
%Fenvalerate remaining(extractable):
______________________________________
Time light clay sandy loam sandy clay loam
____ __________ __________ _______________
sun dark sun dark sun dark
___ ____ ___ ____ ___ ____
3d 22.2 86.0 67.2 90.8 60.4 88.2
10d 12.3 63.6 48.0 85.9 36.6 69.3
% CONH2-Fen(extractable):
________________________
3d 28.4 3.1 4.5 0.8 13.9 2.6
10d 25.7 17.5 7.9 3.3 22.4 9.9
%bound fen:
___________
3d 39.1 3.3 8.1 1.6 6.0 1.6
10d 47.5 6.9 12.8 2.4 9.5 2.7
***********************************************************************
B. Adsorption and transport
________________________
Fenvalerate is reported to move very little in all types of
soils(1,4,5,7). One study found the fenvalerate concentration to be
6-15times higher in the top than in the middle third of a soil
core(1). Another researcher reported 90% recovery of fenvalerate in
the 0-15cm layer with 10% at 15-25cm(9). In clay loam, persistence was
found to occur mainly in the 0-2.5cm layer with <0.5% applied
fenvalerate found in the 2.5-5.0cm layer. This study also reported
very little lateral surface movement(4). The desorption of fenvalerate
is dependent upon the amount of clay and organic matter present. An
equivalent of 20 acre-inches of water resulted in 1-3% leaching with
most fenvalerate staying in the top 3cm(5).
The table below presents data concerning adsorption and transport
of fenvalerate in soil. The reference is given in parentheses at the
end of the title.
Fenvalerate concentration (ppm) with depth after 5 pesticide
applications at 6mo intervals(9)
depth cultivated soil fallow soil (PPM)
______________________________________________________________________
0-15 cm 0.015_0.004 0.011_0.006
15-25 0.001_0.002 0.001_0.001
25-35 TRACE TRACE
***********************************************************************
IV. References (*denotes key reference)
__________
*1.Chapman, R.A., and C.R. Harris. 1981.
J.Environ.Sci.Health.B16(5). 605-15.
____________________
2.Chapman, R.A., C.M. Tu, C.R. Harris, and C. Cole. 1981.
Bull.Environ.Contam.Toxicol. 26. 513-19.
___________________________
3.Harris, C.R., R.A. Chapman, and Carol Harris. 1981. Can.Entomol.
___________________________
4.Talekar, N.S., H.T. Kao, and J. S. Chen. 1983. J.Econ. Ento. 76(4) 711-16.