UNITED
STATES
ENVIRONMENTAL
PROTECTION
AGENCY
WASHINGTON,
D.
C.
20460
OFFICE
OF
PREVENTION,
PESTICIDES
AND
TOXIC
SUBSTANCES
Memorandum
SUBJECT:
BEAD
Preliminary
Assessment
of
the
Impacts
of
Extending
Restricted
Entry
Intervals
for
Methyl
Parathion
Use
on
Cotton,
Field
Corn,
Rice,
Soybean,
Sunflower,
Sweet
Corn,
Sweet
Potato,
and
Walnuts
FROM:
David
W.
Brassard,
Senior
Entomologist
Herbicide
and
Insecticide
Branch
THRU:
Arnet
Jones,
Chief
Herbicide
and
Insecticide
Branch
TO:
Laura
Parsons,
Chemical
Review
Manager
Susan
Lewis,
Chief
Reregistration
Branch
2
Special
Review
and
Reregistration
Division
(
7508C)

PRP
REVIEW
DATE:
December
4,
2002
Background
and
Summary
The
purpose
of
this
memorandum
is
to
summarize
the
impacts
of
extending
restricted
entry
intervals
(
REI's)
for
the
use
of
methyl
parathion
on
cotton,
field
corn,
rice,
soybean,
sunflower,
sweet
corn,
sweet
potato,
and
walnuts.
The
impact
characterizations
contained
in
the
table
were
summarized
from
BEAD's
impact
assessments
for
methyl
parathion
conducted
on
these
crops
(
see
list
of
references).
Because
these
analyses
focused
primarily
on
the
impacts
associated
with
the
unavailability
of
methyl
parathion,
there
was
often
little
or
no
analysis
conducted
on
the
impacts
of
extending
REI's.
In
some
cases,
additional
information
and
characterizations
were
obtained
from
auxiliary
notes
and
personal
communications
provided
from
the
authors
of
these
analyses
and
from
crop
timelines.
The
following
impact
estimates
are
based
on
target
REI's
(
i.
e.
the
number
of
days
required
to
elapse
after
application
to
achieve
a
Margin
of
Exposure
of
100)
provided
by
the
Health
Effects
Division.
BEAD
primarily
focused
on
impacts
associated
with
the
most
commonly
used
formulation
on
each
crop
(
which
generally
accounted
for
96
to100%
of
the
usage
on
these
crops).

The
impacts
of
extending
the
REI
are
estimated
to
be
minor
for
cotton,
rice,
soybeans,
and
2
sunflower
due
to
the
brief
target
REI's
(
4­
6
days)
associated
with
the
use
of
emulsifiable
concentrate
(
EC)
formulations.
In
these
crops
growers
would
continue
to
use
methyl
parathion
and
would
experience
only
minor
inconveniences
in
conducting
cultural
activities
required
to
maintain
their
crops.
The
impacts
of
extending
the
REI
would
be
major
for
field
corn,
sweet
corn,
and
walnuts
due
to
the
longer
REI's
(
14­
52
days)
associated
with
the
use
of
microencapsulated
(
Mcap)
formulations.
These
impacts
would
occur
as
a
result
of
a
long
REI
interfering
with
critical
cultural
activities
and
growers
would
most
likely
switch
to
cost
effective
alternative
insecticides
which
have
shorter
reentry
intervals.
For
sweet
potato,
the
impacts
of
extending
the
REI
would
be
minor
as
long
as
scouting
and
irrigation
pipe
maintenance
activities
are
exempt
from
the
14
day
REI;
otherwise
impacts
would
be
major.
Since
there
are
no
cost
effective
alternatives
to
methyl
parathion
for
use
on
sweet
potatoes,
growers
would
suffer
major
losses
if
the
REI's
were
extended
and
scouting
and
irrigation
pipe
maintenance
activities
were
not
exempted.

Table
1.
Impacts
of
Extending
Restricted
Entry
Intervals
(
REI's)
for
the
Most
commonly
Used
Formulation
Crop
target
REI*
Most
common
form
(%
of
total
crop
usage)
Impact
of
Extending
Restricted
Entry
Intervals
Impacts
of
substitution
of
alternatives**
EC
Mcap
EC
form
Mcap
formulation
cotton
6
11
EC
(
99%)
Minor
Disruptive
to
some
growers
low
field
corn
5
52
Mcap
(
97%)
Minor
Same
as
cancellation
low
rice
4
31
EC
(
99%)
minor
Same
as
cancellation
high
soybeans
4
31
EC
minor
Same
as
cancellation
low
sunflower
4
­­
EC
(
100%)
minor
­­
low
sweet
corn
5
39***
Mcap
(
96%)
minor
Same
as
cancellation
low
sweet
potato
­­
14
Mcap
(
100%)
­­
Minor
if
scouting/
irrigation
pipe
maintenance
are
exempt;
otherwise
impacts
are
major.
High
walnut
­­
25
Mcap
(
100%)
­­
Major
for
applications
made
in
June,
July,
and
August;
minor
for
applications
made
in
April
and
May.
low
­­
not
registered
*
target
REI
is
the
number
of
days
required
to
elapse
after
application
to
achieve
a
Margin
of
Exposure
of
100
**
Impacts
of
substitution
of
alternatives
refer
to
economic
impacts
if
growers
switched
to
alternative
insecticides
***
BEAD
estimated
the
Target
REI
for
sweet
corn
by
extrapolating
from
field
corn
and
reducing
the
REI
proportional
3
to
the
reduction
in
application
rates.

Discussion
of
Crop
Specific
Worker
Activities
and
Impacts
of
Extending
REI's
Cotton
Worker
activities
during
the
growing
season
include
scouting,
irrigation,
some
occasional
hand
weeding,
tillage,
spraying,
and
harvesting.
Insects
are
scouted
throughout
the
growing
season,
generally
twice
a
week.
Scouts
come
into
direct
contact
with
foliage
as
they
go
through
the
fields.
Irrigation
involves
some
worker
activity
in
the
fields.
After
tillage
is
complete,
the
irrigation
pipes
are
assembled
in
the
fields
and
must
be
removed
before
harvest.
Some
entry
into
the
fields
may
also
be
necessary
for
repairs
or
to
manage
the
irrigation.
Most
of
the
irrigation
occurs
in
the
Southwestern
and
Western
U.
S.
Although
hand
weeding
is
infrequent,
it
may
occur
when
workers
are
spot
spraying
a
field
and
can
involve
direct
contact
with
the
plants.
Tillage,
spraying,
and
harvesting
all
occur
using
machinery,
with
the
worker
often
in
an
enclosed
cab.

The
impact
of
extending
the
REI
from
4
(
or
5
in
areas
of
less
than
25"
of
rainfall
annually)
to
6
days
for
the
EC
formulation
(
which
accounts
for
99%
of
methyl
parathion
usage
on
cotton)
would
be
minor.
Extending
the
REI
to
11
days
for
the
microencapsulated
formulation
(
which
accounts
for
1%
of
methyl
parathion
usage
on
cotton)
is
likely
to
result
in
some
disruptions
to
worker
activities
in
the
field
and
would
likely
cause
some
growers
to
substitute
the
EC
formulation
or
other
cost­
effective
alternatives.
(
Gross,
Mosz,
and
Kiely,
2002)

Field
Corn
Worker
activities
during
the
growing
season
include
scouting,
irrigation,
tillage,
spraying,
and
harvesting.
Insects
are
scouted
throughout
the
growing
season.
Scouts
come
into
direct
contact
with
foliage
as
they
go
through
the
fields.
Irrigation
involves
some
worker
activity
in
the
fields.
After
tillage
is
complete,
the
irrigation
systems
are
assembled
in
the
fields
and
must
be
removed
before
harvest.
Some
entry
into
the
fields
may
also
be
necessary
for
repairs
or
to
manage
the
irrigation.
Tillage,
spraying,
and
harvesting
all
occur
using
machinery,
usually
with
the
worker
in
an
enclosed
cab.
BEAD
believes
that
these
activities
are
not
likely
to
result
in
workers
physically
contacting
the
plants.

The
impact
of
extending
the
REI
to
5
days
for
the
EC
formulation
(
which
accounts
for
97%
of
methyl
parathion
usage
on
field
corn)
would
be
minor.
Extending
the
REI
to
52
days
for
the
microencapsulated
formulation
(
which
accounts
for
3%
of
methyl
parathion
usage
on
field
corn)
would
result
in
major
disruptions
to
worker
activities
in
the
field
and
would
cause
growers
to
substitute
the
EC
formulation
or
other
cost­
effective
alternatives.
(
Brassard
and
Alsadek,
2002)

Rice
Methyl
parathion
is
generally
applied
toward
the
end
of
the
season
for
control
of
the
rice
stink
4
bug,
a
late
season
pest.
Worker
activities
during
the
growing
season
include
scouting,
irrigation,
spraying,
and
harvesting.
Scouting
is
generally
conducted
by
walking
the
levees
or
driving
ATV's
(
all
terrain
vehicles)
along
the
levee.
Scouts
will
sometimes
enter
fields
to
check
out
a
problem
more
closely.
Workers
also
maintain
irrigation
in
rice
fields
by
managing
or
maintaining
the
floodwater.
This
is
accomplished
through
pumping
coupled
with
ditch,
canal,
and
levee
management.
Farm
workers
frequently
walk
on
the
levees
or
in
the
fields
to
monitor
water
levels.
Spraying,
and
harvesting
all
occur
using
machinery,
usually
with
the
worker
in
an
enclosed
cab.
BEAD
believes
that
spraying
and
harvesting
activities
are
not
likely
to
result
in
workers
physically
contacting
the
plants.

The
impact
of
extending
the
REI
to
4
days
for
the
EC
formulation
(
which
accounts
for
99%
of
methyl
parathion
usage
on
rice)
would
be
minor.
Extending
the
REI
to
31
days
for
the
microencapsulated
formulation
(
which
accounts
for
1%
of
methyl
parathion
usage
on
rice)
would
result
in
major
disruptions
to
worker
activities
in
the
field
and
would
cause
growers
to
substitute
the
EC
formulation.
(
Cook,
2002;
Shipp,
2002).

Soybeans
Worker
activities
during
the
growing
season
include
scouting,
some
occasional
irrigation
and
hand
weeding.
The
impact
of
extending
the
REI
to
4
days
for
the
EC
formulation
would
be
minor.
Extending
the
REI
to
31
days
for
the
microencapsulated
formulation
would
result
in
major
disruptions
to
worker
activities
in
the
field
and
would
cause
growers
to
substitute
the
EC
formulation
or
other
costeffective
alternatives.
(
Gross
and
Kiely,
2002)

Sunflower
Worker
activities
during
the
growing
season
include
scouting
and
some
occasional
irrigation.
The
impact
of
extending
the
REI
to
4
days
for
the
EC
formulation
would
be
minor
(
Brassard
and
Alsadek,
2002).

Sweet
Corn
BEAD
estimated
the
Target
REI
for
sweet
corn
by
extrapolating
from
field
corn
and
reducing
the
REI
proportional
to
the
reduction
in
application
rates.
Worker
activities
are
more
intense
in
sweet
corn
than
in
field
corn.
Worker
activities
during
the
growing
season
include
scouting,
irrigation,
tillage,
spraying,
and
harvesting.
Insects
are
scouted
throughout
the
growing
season
at
least
once
a
week.
Scouts
come
into
direct
contact
with
foliage
as
they
go
through
the
fields.
Irrigation
involves
some
worker
activity
in
the
fields.
After
tillage
is
complete,
the
irrigation
systems
are
assembled
in
the
fields
and
must
be
removed
before
harvest.
Some
entry
into
the
fields
may
also
be
necessary
for
repairs
or
to
manage
the
irrigation.
Tillage
and
spraying
operations
employ
machinery,
usually
with
the
worker
in
an
enclosed
cab.
BEAD
believes
that
Tillage
and
spraying
are
not
likely
to
result
in
workers
physically
contacting
the
plants.
5
Agricultural
workers
also
come
in
contact
with
the
sweet
corn
crop
during
harvest,
which
is
usually
done
by
hand
in
the
field.
Currently,
over
90
percent
of
sweet
corn
is
hand­
harvested.
The
harvest
workers
wear
gloves
and
dress
in
long­
sleeve
shirts
and
pants
due
to
the
abrasive
nature
of
the
corn
foliage.
Since
sweet
corn
is
planted
at
staggered
dates
within
different
regions
of
Florida,
harvest
occurs
over
an
extended
eight
month
period
during
the
year.
(
Mossler,
2002)

The
impact
of
extending
the
REI
to
5
days
for
the
EC
formulation
(
which
accounts
for
4%
of
methyl
parathion
usage
on
sweet
corn)
would
be
minor.
Extending
the
REI
to
39
days
for
the
microencapsulated
formulation
(
which
accounts
for
96%
of
methyl
parathion
usage
on
sweet
corn)
would
result
in
major
disruptions
to
worker
activities
in
the
field
and
would
cause
growers
to
substitute
the
EC
formulation
or
other
cost­
effective
alternatives
(
Atwood
and
Kiely,
2002).

Sweet
Potatoes
The
only
formulation
used
on
sweet
potatoes
is
the
microencapsulated
Penncap
M.
Alabama,
Arkansas,
Louisiana,
Mississippi,
and
Texas
are
the
only
states
with
with
a
Penncap
M
label
for
sweet
potato.
Scouting
is
the
main
activity
in
fields
during
the
time
of
application
which
typically
occurs
from
May
to
July.
There
are
two
types
of
irrigation
systems
used:
overhead
and
polypipe.
Overhead
irrigation
systems
(
with
a
reel
gun
or
pivot
system)
are
placed
in
the
field
by
a
single
person,
driving
an
enclosed
tractor.
Polypipe
is
laid
across
the
field
rows
from
the
head­
land
and
not
moved
into
the
field.
(
Hammond,
2002;
Poret,
2002).

The
impact
of
extending
the
REI
to
14
days
would
be
minor
if
scouting/
irrigation
pipe
maintenance
are
exempt;
otherwise
impacts
are
major.
Extending
the
REI
to
14
days
for
the
microencapsulated
formulation
(
which
accounts
for
100%
of
methyl
parathion
usage
on
sweet
potato)
would
result
in
major
disruptions
to
worker
activities
in
the
field
and
would
cause
growers
to
substitute
other
alternatives.
Since
existing
alternatives
have
constraints
that
limit
their
usefulness
in
replacing
methyl
parathion,
extending
the
REI's
could
result
in
major
economic
impacts
to
sweet
potato
growers
(
Mallampali,
2002).

Walnuts
Activities
in
the
orchard
during
the
summer
months
include
mowing,
training
young
trees,
vertebrate
pest
and
weed
control,
irrigation
maintenance,
and
harvest.
Pruning
occurs
between
October
and
January,
and
mummy
nut
removal
takes
place
in
the
February
time
frame.

The
impact
of
extending
the
REI
to
25
days
for
the
microencapsulated
formulation
(
which
accounts
for
100%
of
methyl
parathion
usage
on
walnuts)
would
result
in
major
disruptions
to
worker
activities
in
the
field
if
applications
of
methyl
parathion
are
made
in
June,
July,
and
August
Applications
made
in
April
and
May
will
result
in
minor
disruptions
to
cultural
activities.
Irrigation
should
not
require
routine
entry
into
the
field,
except
to
monitor
performance
of
the
system.
However,
scouting
could
be
6
impacted,
even
with
early
season
applications,
unless
all
scouts
are
certified
and
can
be
exempted
under
the
WPS.
(
Cimino
et
al,
2001;
Atwood
and
Alsadek,
2002;
Mosz,
2002).
Insecticide
applications
for
codling
moth
control
usually
begin
in
late
April
and
are
applied
at
2
to
4
week
intervals
until
Early
August
(
Arthropod
Management
Tests,
1999
+
2000).

References
Arthropod
Management
Tests,
1999
+
2000.
Review
5
Efficacy
Tests
for
Application
Dates
for
Codling
Moth
Control.(
Volume
24:
D17;
Volume
25:
D11­
14).

Atwood,
D.
W.
and
J.
Alsadek.
2002.
BEAD
Benefits
Assessment
for
Methyl
Parathion
Use
on
Walnuts.
Internal
Document,
HIB/
BEAD/
OPP,
U.
S.
Environmental
Protection
Agency,
Washington,
DC
20460,
8
pp.

Atwood,
D.
W.
and
T.
Kiely.
2002.
BEAD
Benefits
Assessment
for
Methyl
Parathion
Use
on
Sweet
Corn.
Internal
Document,
HIB/
BEAD/
OPP,
U.
S.
Environmental
Protection
Agency,
Washington,
DC
20460,
16
pp.

Brassard,
D.
W.
and
J.
Alsadek.
2002.
BEAD
Impact
Assessment
for
the
Use
of
Methyl
Parathion
on
Field
corn.
Internal
Document,
HIB/
BEAD/
OPP,
U.
S.
Environmental
Protection
Agency,
Washington,
DC
20460,
16
pp.

Brassard,
D.
W.
and
J.
Alsadek.
2002.
BEAD
Impact
Assessment
for
the
Use
of
Methyl
Parathion
on
Sunflowers.
Internal
Document,
HIB/
BEAD/
OPP,
U.
S.
Environmental
Protection
Agency,
Washington,
DC
20460,
14
pp.

Cimino,
P.,
K.
Davis,
and
D.
Donaldson.
2001.
Biological
Benefits
Assessment
for
Azinphos­
methyl
and
Phosmet
on
Walnuts.
Internal
Document,
HIB/
BEAD/
OPP,
U.
S.
Environmental
Protection
Agency,
Washington,
DC
20460,
9
pp.

Cook,
C.
2002.
Personal
Communication
with
David
W.
Brassard
(
11/
21/
02).
HIB/
BEAD/
OPP,
U.
S.
Environmental
Protection
Agency,
Washington,
DC
20460.

Gross,
W.
and
T.
Kiely.
2002.
Benefits
assessment
for
methyl
parathion
use
on
soybeans.
Internal
Document,
HIB/
BEAD/
OPP,
U.
S.
Environmental
Protection
Agency,
Washington,
DC
20460.

Gross,
W.,
N.
Mosz,
and
T.
Kiely.
2002.
Benefits
assessment
for
methyl
parathion
use
in
cotton.
Internal
Document,
HIB/
BEAD/
OPP,
U.
S.
Environmental
Protection
Agency,
Washington,
DC
20460.

Hammond,
A.
2002.
Personal
Communication
with
Nikhil
Mallampali..
Louisiana
State
University,
7
Baton
Rouge,
LA.

Mallampali,
N.
2002.
Note
to
David
Brassard
regarding
impacts
of
altering
sweet
potato
REI's
(
8­
16­
02).
Internal
Document,
HIB/
BEAD/
OPP,
U.
S.
Environmental
Protection
Agency,
Washington,
DC
20460.

Mossler,
M.
2002.
Florida
Sweet
Corn
Timeline.
University
of
Florida,
Gainesville,
FL,
17
pp.

Mosz,
N.
2002.
Walnut
Timeline.
Internal
Document,
HIB/
BEAD/
OPP,
U.
S.
Environmental
Protection
Agency,
Washington,
DC
20460,
10
pp.

Poret,
R.
2002.
Personal
Communication
with
Nikhil
Mallampali.
President
of
the
Louisiana
Sweetpotato
Growers
Association.

Shipp,
M.
2002.
Rice
Crop
Timeline
for
the
Southern
States
of
Arkansas,
Louisiana,
and
Mississippi.
Louisiana
State
University,
Baton
Rouge,
LA,
67
pp.
