UNITED
STATES
ENVIRONMENTAL
PROTECTION
AGENCY
WASHINGTON,
D.
C.
20460
OFFICE
OF
PREVENTION,
PESTICIDES
AND
TOXIC
SUBSTANCES
Memorandum
SUBJECT:
Responses
to
Questions
Concerning
Disulfoton
Posed
by
Special
Review
and
Reregistration
Division
FROM:
Colwell
A.
Co
ok,
Entom
ologist
Nikhil
Mallampalli,
Entomologist
Herbicide
and
Insecticide
Branch
Anthony
Gilbert,
Eco
nomist
Economic
Analysis
Branch
Biological
and
Economic
Analysis
Division
THROUGH:
David
Brassard,
Senior
Entomologist
Arnet
Jones,
Chief
Herbicide
and
Insecticide
Branch
Biological
and
Economic
Analysis
Division
Arthur
Grube,
Senior
Economist
Economic
Analysis
Branch
Biological
and
Economic
Analysis
Division
BEAD
PEER
REVIEW
DATE:
12
December
2001
TO:
Christina
Scheltema
Michael
Goodis
Betty
Shackleford,
Chief
Special
Review
and
Reregistration
Division
CC:
Denise
Keehner,
Director,
OPP/
BEAD
Introduction
A
meeting
was
held
on
November
28,
2001
between
Special
Review
and
Reregistration
Division
(SRRD)
and
BEAD
concerning
disulfoton.
This
memo
addresses
questions
posed
by
SRRD
during
the
meeting.
The
questions
ranged
from
general
information
to
help
SR
RD
complete
the
IRED
to
verifying
concerns
from
growers.
This
memo
contains
p
roprietary
d
ata
and
is
for
O
PP
use
o
nly.

Questions
And
Answers
1.
The
Pacific
Northwest
(PNW)
primarily
uses
the
liquid
formulation
of
disulfoton
on
potatoes.
Is
the
granular
product
needed
for
use
outside
the
PNW?

Granular
disulfoton
(15G),
like
the
liquid
(8EC),
is
used
at
a
relatively
low
level
nationwide.
However,
more
crop
area
(nationwide)
is
treated
with
granular
than
with
liquid,
according
to
Doane
s
data.
In
2000,
about
11,000
acres
were
treated
with
15G,
8,000
with
8EC.
This
is
equivalent
to
about
1%
of
the
2000
crop
treated
with
15G,
as
compared
to
about
0.6
%
treated
with
8EC.
Some
extension
services
still
list
granular
disulfoton
as
a
pest
control
option,
which
is
presumably
followed
by
growers
in
their
regions.
These
include:
Texas,
North
Dakota,
New
York,
Delaware,
and
Colorado
­
all
states
outside
the
PNW.
Taken
together,
these
results
suggest
greater
reliance
on
granular
disulfoton
in
potato
production
outside
the
PNW.
However,
since
granular
disulfoton
is
used
on
less
than
2%
of
the
national
potato
crop,
its
use
may
reasonably
be
characterized
as
somewhat
low.

2.
There
was
an
SLN
in
1992
for
North
Carolina
peanuts.
Where
is
disulfoton
on
peanuts
used?
What
are
the
formulations
an
d
the
target
pests?

Only
the
granular
formulation
of
disulfoton
is
registered
for
use
on
peanuts.
There
is
a
Section
3
label
for
nationwide
use
on
this
crop.
However,
North
Carolina
has
a
24(
c)
label
that
allows
two
applications
per
season
instead
of
the
sin
gle
applica
tion
allowed
elsewhere.
T
hrips
are
the
m
ain
targeted
p
est,
though
in
so
me
areas
(e
.g.,
Texas),
aphids
are
also
listed
as
targets
(USDA
Crop
Profile)
of
peanuts.
The
main
thrips
species
involved
is
the
tobacco
thrips,
Frankliniella
fusca.
Doane's
data
indicate
usage
in
peanuts
in
the
following
states
in
2000:
Alabama,
Georgia,
North
Carolina,
and
Oklahoma.

3.
Is
it
reasonable
to
narrow
the
scope
of
the
15G
label
to
gladiolus
in
Florida,
deciduous
(birch)
trees
in
New
England
and
New
York
state?
Ho
w
narrowly
ca
n
EPA
define
the
use
of
disulfoton
o
n
ornamentals?

Unknown.
The
ornamental
industry
is
quite
varied,
not
only
because
there
are
well
over
600
species
of
plants
grown
commercially,
but
there
is
little
common
practice
among
nursery
and
floriculture
producers.
We
do
know
that
of
the
4,000
operations
that
responded
to
the
NASS
survey
for
Nursery
and
Floriculture
Chemical
Usage
(to
be
published
Dec.
2001
or
Jan.
2002),
only
22
operations
reported
using
disulfoton
on
a
total
of
56
applications
(about
0.1%
of
reported
pesticide
ap
plications).
W
ith
such
low
rep
orting
NA
SS
will
prob
ably
not
con
duct
much
analyses
with
this
chemical.

BEAD
has
not
been
able
to
verify
the
Am
erican
Nu
rsery
and
La
ndscape
Association

s
claim
that
disulfo
ton
is
critical
to
the
indu
stry
and
rate
red
uctions
belo
w
13
lbs
ai/
A
will
cause
significan
t
harm
to
the
nu
rsery
industry.
Based
o
n
NASS
information
sta
ted
abov
e,
disulfoton
d
oes
not
ap
pear
to
be
critical
to
the
indu
stry.
The
Ca
lifornia
Department
of
Pesticide
Regulation
(CA
DPR,
years
1997­
1999)
database
does
not
have
any
record
of
use
above
6
lbs
ai/
A.
There
are
a
couple
of
growers
of
birch
trees
in
NY
that
do
use
disulfoton
at
the
13
lbs
ai/
A
rate,
but
they
offered
no
evidence
why
such
a
rate
is
necessary.
At
this
time,
BEAD
believes
the
critical
need
of
disulfoton
to
be
low.

4.
How
much
disulfoton
is
used
on
lettuce
and
co
le
crops
in
California,
spe
cifically
the
Salinas
Valley,
vs.
the
rest
of
the
country?
Where
and
how
much
of
the
granular
formulation
of
disulfoton
is
used
for
cole
crops
and
peppers?
If
there
is
no
use
of
the
granular,
does
it
make
sense
to
cancel?

The
table
below
examines
the
amount
of
disulfoton
that
has
been
used
on
the
selected
vegetables
in
CA.
Salinas
Valley
encompasses
Monterey,
San
Benito,
Santa
Clara
and
Santa
Cruz
Counties.
Since
Monterey
County
is
the
largest
prod
uction
area
it
is
the
subject
of
the
table.

Site
Pounds
of
Disulfoton
applied
to
the
Site
in
CA
(3
yr
Average:
1997­
1999)
1
%
of
the
CA
Disulfoton
used
by
Site
in
Monterey
Co.,
CA
Broccoli
8617
60
Brussels
Sprouts
394
87
Cabbage
2
3117
<1
Cauliflower
1114
52
Lettuce,
head
8883
59
Lettuce,
leaf
2377
57
1
Data
from
the
CA
DPR
database
and
includes
years
1997­
1999.
2
Ventura
Co,
not
part
of
Salinas
Valley,
is
maximum
user
of
disulfoton
in
CA,
3
yr
average
of
83%
of
disulfoton
applied
to
cabbage.

Also,
from
the
CA
D
PR
database
(years
1997­
199
9),
an
average
of
85,6
17
lbs
of
disulfoton
was
app
lied
to
36
crops,
about
29%
of
which
was
applied
in
Salinas
Valley.
The
majority
of
disulfoton
was
applied
to
asparagus
(about
45%),
of
which
less
than
10%
is
gr
own
in
Salina
s
Valley,
CA
.

USDA
NASS
Agriculture
Chemical
Usage
Vegetable
Summary
2000
has
limited
information.
The
low
number
of
reports
of
d
isulfoton
are
p
robably
b
ecause
the
u
sage
is
low
on
vegetable
c
rops
othe
r
than
aspara
gus.
Broccoli
Production:
CA,
AZ,
TX;
with
6%
of
CA
broccoli
treated
with
disulfoton
(7,200
lbs).
Cabbage
Production:
CA,
NY
,
TX,
NC;
with
all
states
reporting
some
use.
Only
3%
of
total
cabbage
produced
was
treate
d
with
a
total
of
3
,400
lbs
d
isulfoton
nation
wide.
Cauliflower
Production:
CA,
AZ,
NY;
no
reported
use
in
AZ
or
NY.
Lettuce
Production:
CA,
AZ;
no
reported
use
in
AZ.
Bell
Peppers:
CA,
FL,
NC,
GA;
no
reported
use
in
FL,
NC,
or
GA.

About
85­
87%
of
disulfoton
is
applied
as
the
liquid
formulation
on
asparagus,
broccoli,
cabbage,
cauliflower,
lettuce,
and
peppers,
both
nationally
and
in
California.
If
EPA
cancels
the
granular
formulation
of
disulfoton
on
these
crop
s
the
smaller
gro
wers
would
bear
the
ec
onomic
impact,
either
b
y
investing
in
new
a
pplication
e
quipment,
by
hiring
com
mercial
ap
plicators,
or
n
ot
growing
the
crop.
