UNITED
STATES
ENVIRONMENTAL
PROTECTION
AGENCY
WASHINGTON,
D.
C.
20460
OFFICE
OF
PREVENTION,
PESTICIDES
AND
TOXIC
SUBSTANCES
Memorandum
SUBJECT:
Benefits
of
Disulfoton
on
Selected
Vegetable
Crops
and
Cotton
FROM:
Colwell
Cook,
Entomologist
Herbicide
and
Insecticide
Branch
Biological
and
Economic
Analysis
Division
THROUGH:
David
Brassard,
Senior
Scientist
Jonathan
Becker,
Team
Leader
Arnet
Jones,
Chief
Herbicide
and
Insecticide
Branch
Biological
and
Economic
Analysis
Division
REVIEWED
BY
PRP:
September
26,
2001
TO:
Christina
Scheltema
Betty
Schakleford
Reregistration
Branch
Special
Review
and
Reregistration
Division
(7508C)

CC:
Denise
Keehner,
Director
Biological
and
Economic
Analysis
Division
SUMMARY
All
applications
of
disulfoton
on
the
crops
in
this
assessment
are
made
by
groundboom.
Cole
crops,
lettuce,
chili
peppe
rs
use
the
liquid
formulation,
w
hich
is
either
shan
k
injected
o
r
in­
furrow
at
pla
nt.
Disulfoton,
b
oth
granular
and
liquid,
is
currently
applied
in­
furrow
at
plant
on
cotton
and
beans,
snap
and
lima.
BEAD
believes
that
the
cotton
an
d
bean
gr
owers
would
switch
to
gra
nular
if
the
liquid
fo
rmulation
wa
s
no
longer
a
vailable.

Background
Special
Review
and
Reregistration
Division
(SRRD)
has
asked
BEAD
to
evaluate
the
benefits
of
disulfoton
for
lima
beans,
snap
beans,
cole
crops,
lettuce,
chili
peppers,
and
cotton.
The
Health
Effects
Division
(HED)
has
calculated
the
margins
of
exposure
(MOE)
to
be
of
concern
for
mixer/
loaders
and
handlers.
For
the
EC
formulation
of
disulfoton,
the
MOEs
were
calculated
to
be
20
and
30,
for
mixer/
loader
and
handler,
respectively.
For
the
granular
form
ulation,
HE
D
has
calc
ulated
M
OEs
of
8
00
and
9
6
for
mixer/
lo
ader
and
handler,
resp
ectively.
Additionally,
aerial
applications
have
much
lower
MOEs
than
do
groundboom
applications
for
mixer/
loader
and
handler.
Postapplication
risks
were
calculated
for
those
sites
that
allowed
foliar
application.
In
this
assessment,
that
includes
only
cotton,
which
had
an
MOE
of
108
one
day
after
treatment.
Therefore,
post
application
activities
have
not
been
inc
luded
in
this
asse
ssment.
2
SRRD
has
requested
that
BEAD
investigate
the
importance
of
liquid
and
granular
formulations,
and
aerial
applications
of
disulfoton.

Cole
Crops
and
Chili
Pepp
ers
Cole
crops
assessed
include
broccoli,
cauliflower,
cabbage,
and
Brussels
sprouts.
Chili
pepper
production
is
similar
to
the
co
le
crops
an
d
the
pest
pr
oblems
ar
e
the
same,
so
it
is
included
in
this
sec
tion.
The
m
ajority
of
cole
crops
produc
tion
occurs
in
California.
New
M
exico
produces
most
chili
peppers
in
the
United
States.
Most
disulfoton
applied
to
these
crops
is
in
California.
Use
of
disulfoton
has
been
decreasing,
probably
due
to
the
recent
registration
of
im
idacloprid
.

Disulfoton
is
u
sed
to
con
trol
several
sp
ecies
of
aph
ids
on
cole
crops
and
chili
peppe
rs;
it
is
especially
efficacious
against
the
cabbage
aphid.
It
is
shank
injected
when
the
plants
are
4­
5
weeks
old
and
the
aphids
have
exceeded
the
economic
threshold.
The
formulation
of
disulfoton
used
is
based
upon
the
fertilizers,
fungicides
or
herbicide
s
that
will
be
shank
injected
at
the
same
time,
usu
ally
the
liquid
form
ulation.

Currently,
imid
acloprid
is
a
pplied
at­
p
lant,
but
imidac
loprid
alo
ne
cannot
control
the
ca
bbage
aphid
throughout
the
entire
growing
season
due
to
its
limited
period
of
residual
effectiveness.
Imidacloprid
is
not
effective
as
a
foliar
app
lication.
The
refore,
orga
nophosp
hates
are
still
nece
ssary
to
insure
ap
hid­
free
head
s
or
florets.
Alternatives
to
disulfoton
are
oxydemeton­
methyl
and
dimethoate.
Chlorpyrifos
is
also
registered,
but
it
is
injurious
to
beneficial
ins
ects
and
has
some
phyto
toxicity
prob
lems
at
the
high
ra
tes
required
to
control
the
cabbage
aphid.

Lettuce
Most
of
the
United
States
iceberg
lettuce
(96%)
and
leaf
lettuce
(97%)
is
produced
in
California
and
Arizona.
California
treated
about
2­
3%
of
the
iceberg
and
1%
of
the
leaf
lettuce
acreage
with
disulfoton
in
1999
(Kurtz,
pe
rsonal
com
munication;
CA
Pestic
ide
Use
R
eport
data
,
1999).

The
primary
pest
targeted
by
disulfoton
on
lettuce
is
the
root
aphid
.
Disulfoton
is
applied
at­
plant
or
as
a
pre­
plant
application
and
incorporated
into
the
soil.
It
is
only
applied
in
the
liquid
formulation
since
the
site
was
removed
from
the
granular
label
in
the
late
1990s.
It
is
not
shank
injected
because
this
would
put
the
active
ingredient
below
the
shallow
root
system
of
the
lettuce
plants
(Kurtz,
personal
communication).

The
recent
decline
in
d
isulfoton
use
o
n
lettuce
may
ha
ve
occurred
due
to
the
registration
o
f
imidaclop
rid
and
a
strong
program
to
remove
Lombardy
Poplar
trees
from
residential
and
park
areas.
The
poplar
trees
are
a
primary
host
for
the
root
aphid.
The
reduction
of
these
ornamentals
near
lettuce
production
has
reduced
the
root
aphid
populations
enough
for
imidacloprid
to
control
most
problems.
However,
there
are
still
a
few
hot
spots

of
root
aphids
and
these
are
the
areas
that
still
require
disulfoton
applications.
There
are
no
other
effective
alternatives
to
this
particular
aphid.

Beans,
Lima
and
Snap
Fresh
lima
beans
are
primarily
produced
in
Georgia.
Disulfoton
is
applied
at­
plant
to
control
thrips.
Based
on
a
survey
o
f
county
extensio
n
agents,
Dr
.
Adams
re
ported
tha
t
anywhere
fro
m
20­
30%
of
lima
b
ean
growers
in
Georgia
use
disulfoton
,
both
liquid
a
nd
granular
formulations
.

The
only
alternative
for
thrips
for
lima
beans
would
be
foliar
applications
of
acephate.
Imidacloprid
is
not
registered
for
this
vegetable,
and
the
expense
would
prohibit
its
use
if
it
should
get
registered
(Adams,
personal
communication).

The
crop
profiles
for
snap
bean
production
in
Michigan
does
not
recommend
disulfoton.
Although,
other
3
Michigan
publications
recommend
the
granular
formulation
at
plant
(Rosenbaum,
personal
communication).
The
New
York
crop
profile
recommends
only
in­
furrow
application
at­
plant
for
potato
leafhoppers.
However,
extension
entomologists
at
Cornell
do
not
recommend
disulfoton
as
part
of
an
IPM
strategy.
The
potato
leafhop
per
is
a
sporadic
pest
and
d
oes
not
req
uire
contro
l
every
year.
T
hey
advise
gr
owers
to
wa
it
until
they
have
a
p
roblem
with
the
insects
befo
re
treating,
and
then
applying
acephate,
carbaryl,
me
thomyl
or
dimethoate.
D
isulfoton
is
still
recommended
at­
plant
if
neighbo
ring
fields
have
identified
pro
blems
with
potato
leafho
pper.
Ad
ditionally,
processo
rs
will
disqualify
any
b
eans
treated
with
systemic
insec
ticides
at­
plant
un
less
the
abov
e
condition
is
substantiated
by
extension
agents
(Pe
tzoldt,
perso
nal
communication).

Disulfoton
is
applied
to
beans
as
either
a
liquid
or
granular
formulation.
The
formulation
decision
appears
to
be
based
upon
whether
the
grower
is
applying
fertilizer
or
herbicide
at
the
same
time.
Although
there
is
limited
information
to
accurately
a
ssess
impact
of
eliminating
the
liq
uid
formulation,
BEA
D
believe
s
that
doing
so
would
not
be
a
pr
oblem
to
the
majority
o
f
growers.
H
owever,
the
re
is
a
need
fo
r
disulfoton
in
lim
a
bean,
and
occassion
ally
in
snap
bea
n,
produc
tion.

Cotton
Disulfoton
is
the
insecticide
of
c
hoice
in
area
s
that
use
clom
azone
to
c
ontrol
the
we
eds:
velvetlea
f,
primrose,
and
mo
rning
glory.
Clomazone
is
the
herb
icide
of
choice
in
these
areas
bec
ause
it
is
very
effective
against
these
weeds
and
is
less
cos
tly
than
the
other
h
erbicides.
D
isulfoton
wor
ks
as
a
safener
w
hen
clomazone
is
used
.
Disulfoton
is
a
pplied
in­
furro
w
with
the
seed
,
while
clomaz
one
is
app
lied
as
a
ban
d
on
top.
T
he
liquid
form
ulation
is
preferred
as
it
appears
to
be
a
better
safener
and
more
effective
than
the
granular
formulation
at
protecting
the
cotton
seedlings
against
thrips.
However,
the
alternative,
phorate,
is
applied
as
a
granular
formulation
although
it
is
not
as
efficacious
against
the
thrips.
Another
alternative,
aldicarb,
is
very
effective
against
thrips
but
do
es
not
act
as
a
safener.
(Lentz
and
Leona
rd,
personal
comm
unications)

Use
of
disu
lfoton
in
cotto
n
has
been
declining.
T
his
has
been
attributed
to
the
introduction
of
glyphosate
tolerant
(round­
up­
ready®)
cotton.
However,
the
percentage
of
acreage
that
can
be
planted
with
glyphosate
tolerant
cotton
is
restricted.
Therefore,
in
areas
without
the
modified
cotton,
herbicides
that
are
efficacious
against
the
aforementioned
weeds
are
still
necessary
and
subsequently
so
is
disulfoton
(Adams
and
Leonard,
personal
communications).
The
cotton
growers
would
probably
switch
to
the
granular
formulation
if
the
liquid
formulation
was
no
longer
available.

Maximum
Acres
Treated
Cole
Crops
and
Chili
Pepp
ers
According
to
Mr.
B
reschini,
a
custo
m
applica
tor,
his
comp
any
applies
d
isulfoton
on
up
to
40
acre
s/
day,
maximum,
usually
less.
He
said
that
it
is
shank
injected
with
fertilizer,
when
the
plants
are
about
4
to
5
weeks
old,
and
the
co
nsultants
have
b
een
identifying
a
phid
pro
blems.
Ad
ditionally,
if
the
area
is
having
an
ap
hid
outbre
ak,
his
company
may
apply
disulfoton
for
u
p
to
4
wee
ks,
but
has
nev
er
applied
it
more
than
3
times
in
one
we
ek,
and
usua
lly
only
twice
a
week.
Also,
as
a
commercial
applicator,
the
company
has
several
mixer/
loaders
and
applicators,
so
Mr.
Breschini
said
it
is
highly
impro
bable
that
the
same
peo
ple
would
be
making
all
the
disulfoton
application
s.

Lettuce
Lettuce
in
California
is
usually
planted
in
blocks
of
8­
12
acres.
Planting
is
staggered
so
that
growers
can
harvest
throughout
the
growing
season.
Disulfoton
is
applied
in
liquid
formulation
with
herbicide
at
planting.
The
maximum
acreage
that
could
be
treated
in
one
day
is
40,
although
20
acres
a
day
is
probably
more
likely.
With
a
commercial
applicator,
there
may
be
2
to
3
days
of
planting
in
a
row,
however,
it
would
be
unlikely
that
the
same
4
application
team
would
be
making
all
of
the
applications.
A
private
grower
would
be
only
able
to
plant
2
blocks
or
about
40
acres
in
a
day.
It
is
unlikely
the
private
grower
would
plant
more
at
one
block
at
a
time,
otherwise,
the
staggering
plan
would
not
be
in
effect
(Kurtz,
Platts,
personal
communications).

Cotton
Southern
c
otton
farms
te
nd
to
be
ab
out
1,000
Acres
+/­
10
%.
Gro
wers
usually
ow
n
2
or
3
p
lanters.
Generally
a
planter
can
plant
100
­150
A/
d
ay.
Under
most
circum
stances
a
gro
wer
will
have
his
fa
rm
planted
within
3
days;
however,
the
process
can
take
up
to
7­
10
interrupted
days
if
problems
arise
(weather,
usually)
(Leonard,
personal
communication)

References
Agricultural
Statistics
2000.
NASS,
USDA
Agricultural
Statistics
2001.
NASS,
USDA
California
P
esticide
Use
Reports
d
ata,
1999
.

Crop
Profile
for
Peppers
(Chile)
in
New
Mexico.
March
2000.
USDA
Crop
Profile
for
Broccoli
in
California.
August
1999.
USDA
Crop
Profile
for
Brussels
Sprouts
in
California.
November
1999.
USDA
Crop
Profile
for
Cabbage
in
California.
2000.
USDA
Crop
Profile
for
Cauliflower
in
California.
January,
2000.
USDA
Crop
Profile
for
Cotton
in
Alabama.
Prepared
December
1999.
USDA
Crop
Profile
for
Cotton
in
Arkansas.
Prepared
August
1999.
USDA.

Crop
Profile
for
Cotton
in
Tennessee.
December,
1998.
USDA.

Crop
Profile
for
Cotton
in
Texas.
Prepared
September
1999.
USDA.

Crop
Profile
for
Lettuce
(Iceberg)
in
California.
March
1999.
USDA.

Crop
P
rofile
for
Lettuc
e
(Leaf)
in
Ca
lifornia.
April
1
999.
USDA.

Crop
P
rofile
for
Be
ans
(Snap
)
in
Michiga
n.
Prepar
ed
August
1999.
U
SDA.

Jackson,
L
.,
K.
Mayb
erry,
S.
Ko
ike,
F.
Laem
mlen,
K.
Sc
hulback,
an
d
W.
Chaney.
Leaf
L
ettuce
Pro
duction
in
California.
U
niversity
of
Califo
rnia,
Division
of
Agriculture
and
Natu
ral
Resour
ces,
Public
ation
721
6.

David
Adams.
Extension
Ento
mologist,
U
niversity
of
Ge
orgia.

Les
Breschini.
John
P
ryor
and
C
ompany,
Salinas,
Califor
nia
(a
profes
sional
fertilizer
co
mpany)

Edward
A.
Kurtz.
California
Lettuce
Research
Board.
5
Gary
Lentz.
Cotton
E
ntomologist.
University
of
T
ennessee

Knoxville
Roger
Leonard.
C
otton
Ento
mologist,
Lo
uisiana
State
U
niversity.

Curtis
Petzo
ldt.
Vegetab
le
IPM
Co­
ordin
ator,
Corn
ell
University.

Belinda
P
latts.
Pest
Con
trol
Agent.
D
ole
Fresh
F
oods.

Robin
Rosenbaum.
Pesticide
Registration
P
rogram
M
anager,
M
ichigan
De
partment
o
f
Agriculture.

Ron
Smith.
Cotton
E
xtension
En
tomologist.
Auburn
U
niversity.
