UNITED
STATES
ENVIRONMENTAL
PROTECTION
AGENCY
WASHINGTON,
D.
C.
20460
April
13,
2005
OFFICE
OF
PREVENTION,
PESTICIDES
AND
TOXIC
SUBSTANCES
Memorandum
SUBJECT:
Benefits
Assessment
for
Dicofol
on
Citrus:
Oranges,
Grapefruit,
Tangerines,
and
Tangelos
FROM:
Don
Atwood,
Entomologist
Biological
Analysis
Branch
Steve
Smearman,
Economist
Economic
Analysis
Branch
Biological
and
Economic
Analysis
Division
(
7503C)

THRU:
Arnet
Jones,
Branch
Chief
Biological
Analysis
Branch
David
Widawsky,
Branch
Chief
Economic
Analysis
Branch
Biological
and
Economic
Analysis
Division
(
7503C)

Peer
Review
Panel
Date:
December
15,
2004
TO:
Mika
Hunter,
Chemical
Review
Manager
Special
Review
Branch
Special
Review
and
Reregistration
Division
(
7508C)

SUMMARY
BEAD
was
asked
by
SRRD
to
determine
the
biological
and
economic
impacts
of
extending
the
restricted
entry
intervals
(
REI's)
for
dicofol
use
on
citrus
based
on
worker
exposure
concerns
of
HED.
Dicofol
is
applied
to
citrus
to
control
a
complex
of
mites
including
spider
mites
and
rust
mites.
Citrus
are
primarily
produced
in
Arizona,
California,
Florida,
and
Texas
in
the
US.
This
analysis
assesses
the
use
of
dicofol
to
control
mites
on
oranges,
grapefruit,
tangerines
and
tangelos.
No
significant
usage
of
dicofol
was
found
on
oranges,
tangelos,
or
tangerines.
The
only
citrus
crop
of
concern
is
grapefruit
with
primary
usage
in
Texas
(
25%
of
crop
treated).
BEAD
believes
that
there
will
be
no
impact
on
grapefruit
production
in
Texas
if
dicofol
REI's
are
extended,
as
dicofol
use
will
be
shifted
in
the
rotational
spray
program
to
a
period
where
field
activities
will
not
be
restricted
In
addition,
even
with
an
extended
REI,
dicofol
2
application
would
still
be
an
option
during
the
non­
harvest
period
(
June­
Sept).
Regardless,
numerous
alternative
miticides
are
available
which
are
both
efficacious
and
cost
effective.
BEAD
believes
there
would
be
no
biological
or
economic
impact
from
extension
of
the
dicofol
REI.

BACKGROUND
Citrus
production
begins
with
grove
establishment
or
replacement.
In
general,
the
average
rate
of
grove
replacement
is
3%
annually.
Trees
do
not
produce
fruit
for
the
first
3
years.
At
any
time
commercial
groves
contain
90%
bearing
trees.
Trees
are
commonly
spaced
in
a
15­
feet
square
pattern
yielding
194
trees
per
acre.
This
spacing
provides
an
almost
continuous
canopy
and
maximizes
land
use,
water
and
energy.
Bearing
trees
are
mechanically
hedged
to
keep
row
middles
open
for
harvesting
operations
and
to
allow
maximum
light
penetration.
All
hedging
and
tree
topping
occurs
following
harvest.
Trees
are
topped
at
a
height
which
will
allow
pickers
access
to
all
fruit
using
20­
foot
ladders.
Hand
pruning
is
only
done
after
catastrophic
incidents.

About
60%
of
new
leaf
growth
appears
in
the
spring
with
the
remainder
occurring
in
late
summer.
Flowering
also
begins
in
March
for
most
citrus.
Except
for
Valencia
oranges,
most
citrus
only
have
one
crop
of
fruit
on
the
trees
after
bloom.
The
bloom
period
affects
the
timing
of
pest
control
operations
as
well
as
the
setting
of
bees
for
pollination,
highly
important
for
citrus
hybrids.
Irrigation
must
be
set
to
water
trees
during
bloom
and
early
fruit
set.
Irrigation
is
also
used
for
freeze
protection
for
trees
up
to
5
years
of
age.
Ninety­
five
percent
of
acreage
now
uses
micro­
sprinkler
systems
for
under
canopy
irrigation.

Unlike
other
fruit,
citrus
must
mature
on
the
tree.
Fruit
must
be
sampled
to
determine
the
amount
of
sugar
prior
to
harvest
and
the
acid
to
sugar
ratio.
In
Florida,
85%
of
orange
production
is
for
processing
with
the
rest
fresh
marketed.
Grapefruit
and
tangerine/
hybrids
are
produced
for
the
fresh
market
in
Florida.
Rind
color
and
quality
are
crucial
only
to
the
fresh
fruit
market.
Rejected
fresh
fruit
is
processed
and
may
result
in
approximately
half
of
the
grapefruit
and
tangerine/
hybrids
being
processed.
Citrus
fruit
ripens
throughout
the
year
based
on
species
or
variety.
Harvest
occurs
thoughout
the
year.
Approximately
97%
of
citrus
is
hand
harvested.
Oranges,
grapefruit,
and
tangerines/
hybrids
mature
and
are
ready
to
be
picked
in
all
months
but
September
and
August.

There
are
five
periods
during
which
pesticides
are
applied.
Post
bloom
sprays
take
2
­
7
weeks
to
complete
and
are
targeted
at
citrus
rust
mites.
The
second
spray
is
often
the
same
as
the
first
spray
and
is
applied
over
5
weeks
between
mid­
April
and
the
end
of
May.
The
third,
summer
spray,
occurs
in
June
or
July
and
is
generally
a
petroleum
oil
spray,
though
it
may
also
contain
other
active
ingredients.
The
fall
spray
is
conducted
after
mid­
August
through
year
end.
These
sprays
are
often
miticides
to
control
rust
and/
or
spider
mites
on
fresh
market
fruit.
A
fifth
spray
can
occur
as
a
supplement
to
the
fall
spray
on
as
needed
basis.

PRODUCTION,
USE
AND
USAGE
DATA
3
In
2003,
citrus
was
produced
on
983,600
acres
in
the
US,
classifying
citrus
as
a
major
crop
(
Table
1).
Oranges
accounted
for
77.4%
of
citrus
acreage
followed
by
grapefruit
(
11.7%),
lemons
(
6.1%),
tangerines
(
3.8%)
and
all
others
at
less
than
1%
of
total
acreage
in
production.
Nationally
in
2003,
approximately
69%
of
the
citrus
acreage
was
in
Florida
followed
by
California
with
25.4%,
Arizona
(
2.8%)
and
Texas
(
2.8%)
(
Table
2).

Table
1.
US
citrus
production
in
2003.
(
Citrus
Fruits
2003
Summary,
USDA/
NASS)

Crop
Bearing
Acreage
(
Acres)
Production
(
1000
tons)
Value
of
Production1
(
1000
$)

Oranges
761400
12,930
1,645,856
Grapefruit
114800
2,152
296,777
Lemons
59800
798
269,753
Limes2
NA
NA
NA
Tangelos3
8000
45
9871
Tangerines
36200
435
125301
Temples
3,400
63
4806
1
Packinghouse­
door
equivalents
2
Estimates
discontinued
as
of
2002­
03
crop
3.
Florida
Only.

Table
2.
2003
Citrus
production
by
State.
(
Citrus
Fruits
2003
Summary,
USDA/
NASS)

State
Bearing
Acreage
(
Acres)
Production
(
1000
tons)
Value
of
Production1
(
1000
$)

Arizona
27,300
163
41393
California
250000
2917
908381
Florida
679000
13045
1372795
Texas
27300
298
29795
US
983600
16423
2352364
1
Packinghouse­
door
equivalents
By
crop
and
State,
Florida
led
all
States
in
2003
in
all
citrus
production
with
79%
of
production.
587,600
acres
or
75
percent
of
the
oranges
were
produced
in
Florida
with
the
remainder
grown
in
California
(
Table
3).
Florida
also
accounted
for
the
lion's
share
of
the
grapefruit
production
as
well
with
95,500
acres
or
75
percent
followed
by
Texas
with
18,500
4
acres
or
14.5
percent
and
California
with
13,500
acres
or
10.5
percent.
For
tangerines,
Florida
accounted
for
21,700
of
the
33,900
acres
produced
or
64
percent
with
California
producing
the
remaining
35
percent.
For
tangelos,
Florida
accounted
for
all
of
the
9,100
acres
in
production.

On
the
national
level,
less
than
2%
of
citrus
acres
are
treated
with
dicofol.
Data
indicates
that
dicofol
usage
on
tangelos
in
Florida,
all
US
production,
is
less
than
1%
of
the
total
crop
(
personal
communication
with
Phil
Stansley).
Less
than
5%
of
tangerines,
primarily
Arizona,
are
treated
annually
with
dicofol.
Dicofol
usage
on
oranges
is
2%
of
the
crop
treated
annually.
In
contrast,
national
dicofol
usage
on
grapefruit
is
7%
of
acres
treated.
At
the
State
level,
Texas
has
the
greatest
dicofol
usage
with
25%
of
the
grapefruit
acreage
treated.
Due
to
the
minor
use
of
dicofol
on
oranges,
tangelos,
and
tangerines,
only
dicofol
use
on
Texas
grapefruit
is
addressed
in
this
analysis.

TARGET
PEST
FOR
DICOFOL
ON
GRAPEFRUIT
The
mite
pests
in
Texas
grapefruit
include
rust
mites
(
citrus
rust
mite)
and
spider
mites
(
citrus
red
mite,
Texas
citrus
mite,
and
false
spider
mite).
Many
factors
are
involved
which
affect
mite
abundance
and
potential
for
injury
to
the
tree
and
crop.
Reduction
or
elimination
of
pesticides
such
as
copper,
copper
plus
oil,
and
sulfur
can
avoid
flare­
ups
of
secondary
pests
such
as
spider
mites
to
primary
pest
status.
Spider
mites
are
generally
controlled
during
normal
spray
routines
for
managing
rust
mites.
It
is
recommended
that
all
insecticides,
other
than
petroleum
oil,
should
be
used
only
once
a
year
to
minimize
development
of
resistant
populations.
Mite
build
up
in
the
spring
and
summer
is
not
as
much
concern
as
during
the
fall.

Citrus
rust
mite
­
Citrus
rust
mite
is
an
important
pest
of
fruit
grown
for
the
fresh
market.
The
citrus
rust
mite
feeds
on
both
fruit
and
foliage.
Feeding
on
fruit
generally
occurs
when
the
fruit
is
0.5
inch
or
larger.
Surface
feeding
on
fruit
causes
cell
destruction
and
ultimately
a
russeting
appearance.
On
severely
damaged
fruit
the
rind
will
crack.
Rust
mite
damage
during
exponential
growth,
before
fruit
maturity,
may
result
in
smaller
fruit.
While
the
primary
effect
of
fruit
damage
caused
by
rust
mites
appears
to
be
a
reduction
in
grade,
other
conditions
have
been
associated
with
severe
fruit
injury
that
include
reduced
size,
increased
water
loss,
and
increased
drop.
Female
citrus
rust
mites
lay
an
average
of
20
eggs
on
fruit
or
leaf
surfaces.
The
entire
rust
mite
life
cycle
can
be
completed
in
7­
10
days
in
the
summer,
but
may
take
20
or
more
days
in
the
winter.
Numerous
overlapping
generations
can
occur
during
a
single
season.

Texas
citrus
mite
­
Texas
citrus
mite
is
among
the
most
destructive
pests
of
citrus
fruits.
Texas
citrus
mite
feeding
injury
is
characterized
by
minute
chlorotic
spots
that
gradually
become
so
abundant
that
infested
leaves
take
on
a
silvery
appearance.
Heavy
feeding
damage
can
cause
defoliation,
which
is
generally
more
severe
in
early
fall.
These
mites
primarily
feed
on
upper
leaf
surfaces
and
seldom
on
fruit.
Under
favorable
conditions,
a
generation
of
the
Texas
citrus
mite
may
be
completed
in
3
weeks.
Populations
are
hampered
by
high
humidity
and
rainfall.

Citrus
red
mite
­
Citrus
red
mite
feeds
on
both
leaves
and
fruit.
On
leaves,
citrus
red
mite
5
feeding
results
in
a
pale
stippling
visible
primarily
on
the
upper
surface
of
the
leaf.
In
severe
infestations,
the
stippling
enlarges
to
dry
necrotic
areas
(
commonly
called
mesophyll
collapse).
Eventually,
leaves
may
drop
and
twigs
dieback.
Defoliation
is
especially
severe
when
trees
under
water
stress
are
subject
to
drying
winds.
Stippling
or
silvering
also
occurs
on
green
fruit
but
usually
disappears
when
fruit
change
color.
If
large
populations
feed
on
nearly
mature
fruit,
the
silvering
may
persist.
High
populations
can
also
cause
fruit
sunburn
during
hot
weather
as
result
of
defoliation.
Each
red
mite
female
lays
from
20­
50
eggs
along
the
mid­
rib
on
both
the
top
and
bottom
of
citrus
leaves.
The
entire
life
cycle
can
be
completed
in
as
short
as
3
weeks
during
the
summer,
but
development
may
take
5
or
more
weeks
in
the
winter.

False
spider
mite
­
False
spider
mites
feed
on
fruit
and
leaves
causing
undesirable
blemishes
referred
to
as
`
nail
head'
rust.
False
spider
mites
are
most
numerous
in
the
interior
tree
canopy,
where
fruit
spotting
generally
first
appears.
Spots
are
brown,
irregular­
shaped
pin
points
to
1/
4
inch,
or
larger,
in
diameter
and
are
often
raised.
Spotting
occurs
on
any
part
of
the
fruit
and
less
frequently
on
upper
and
lower
leaf
surfaces.
In
extreme
cases
the
spots
coalesce
to
cover
large
areas
on
fruit
and
leaves.
Each
female
lays
an
average
of
25
eggs
which
are
glued
singly
to
the
leaf
surface.
Developmental
time
from
egg
to
mature
adult
requires
nearly
4
weeks
in
the
summer.
Several
false
spider
mite
generations
can
occur
in
a
single
season.

The
need
for
chemical
treatments
to
control
mites
is
dictated
by
numerous
biological
attributes
of
the
mites,
marketing
objectives
for
the
fruit,
and
horticultural
practices.
These
key
biological
factors
include:
1)
inherent
ability
of
mites
to
quickly
increase
to
injurious
densities
on
fruit
and
sustain
the
potential
for
reproductive
increase
over
time;
and
2)
small
size,
which
makes
it
difficult
to
monitor
population
densities
in
the
field
and
detect
injurious
levels
until
visible
injury
has
occurred
on
the
fruit.
The
marketing
objective
for
fruit
is
particularly
important.
Cosmetic
appearance
is
a
priority
for
fruit
grown
for
the
fresh
market.
Fruit
growth
and
abscission
are
not
affected
until
50
to
75%
of
the
surface
has
been
injured.
Thus,
there
is
reduced
justification
for
chemical
control
of
rust
mites
on
fruit
grown
for
processing.
Citrus
groves
producing
fruit
designated
for
the
fresh
market
may
receive
three
or
four
miticides
per
year.
In
contrast,
groves
producing
fruit
designated
for
processing
receive
zero
to
two
treatments
per
year.

Spider
mites
are
suppressed
to
low
densities
by
several
species
of
predacious
mites,
insects,
and
entomopathogens
in
some
groves.
However,
when
populations
averaging
5
to
10
motile
spider
mites
per
leaf
develop
between
September
and
May
it
would
be
reasonable
to
apply
a
miticide,
especially
if
the
trees
are
stressed.
However,
infestations
comprised
predominantly
of
adults,
particularly
males,
are
in
decline
and
would
not
require
control.
Adult
mites
are
recognized
by
their
large
size
relative
to
immatures
and
females
distinguished
by
their
round
shape
and
shorter
legs
compared
to
males.

Need
for
controlling
spider
mites
is
based
on
temperature
and
humidity
conditions,
spider
mite
population
levels,
tree
vigor,
and
time
of
the
year.
Petroleum
oil
provides
some
ovicidal
activity
against
spider
mite
eggs.
None
of
the
other
miticides
provide
ovicidal
activity,
and
their
residual
activity
must
be
sufficiently
long­
lasting
to
kill
subsequently
emerging
larvae.
6
ALTERNATIVE
MITICIDES
FOR
USE
ON
GRAPEFRUIT
There
are
a
number
of
efficacious
miticides
available
to
control
rust
mites
and
spider
mites
on
Texas
grapefruit
(
Table
3).
Dicofol
is
only
considered
helpful
for
rust
mite
control
but
is
considered
effective
against
spider
mites.
Table
4
provides
the
recommended
spray
program
for
grapefruit
in
Texas.

Table
3.
Efficacious
alternatives
to
dicofol
to
control
rust
and
spider
mites
on
Texas
grapefruit
and
their
cost.

Pest
Miticide
Rate/
Acre
REI
(
hours)
Cost/
Acre
($)

Rust
Mite
abamectin
10­
20
oz
12
NA*

formetanate
hydrochloride
½
­
1
1/
4
lb
48
29.83
diflubenzuron
6.25
oz
12
NA
pyridaben
5.2­
10.67
oz
12
29.83
aldicarb
33
lb
48
121.00
fenbutatin
oxide
2­
3
lb
48
42.16
oxamyl
2­
4
pt
48
NA
dicofol
6
pt
12
11.45
Spider
Mite
propargite
2­
3
pt
48
NA
fenpropathrin
16­
21oz
24
NA
pyridaben
5.2­
10.67
oz
12
29.83
fenbutatin
oxide
2­
3
lb
48
42.16
dicofol
6
pt
12
11.45
*
NA
=
Not
Available
7
Table
4.
Spray
program
for
Texas
grapefruit
Timing
Months
Pest
Miticide
Postbloom
March­
May
Rust
&
Spider
Mite
fenbutatin
oxide
dicofol
pyridaben
fenpropathrin
Rust
Mite
abamectin
+
oil
diflubenzuron
+
oil
formetanate
hydrochloride
oxamyl
Rust
Mite
&
Citrus
Nematode
aldicarb
Summer
June­
July
Rust
Mites
abamectin
+
oil
diflubenzuron
+
oil
fenbutatin
oxide
Late
Summer­
Fall
August­
October
All
Mites
fenbutatin
oxide
dicofol
pyridaben
fenpropathrin
Winter
November­
Spider
Mites
propargite
(
no
oil)

IMPACT
OF
INCREASED
RESTRICTED
ENTRY
INTERVALS
The
current
REI
for
dicofol
application
on
grapefruit
is
12
hours.
New
labeling
increases
the
REI
to
58­
87
days
for
high
contact
activities
(
harvest)
and
from
46­
71
days
for
medium
contact
activities
(
pruning),
the
only
activities
of
concern,
depending
on
whether
applied
at
maximum
or
minimum
rate.
Appendix
A
provides
information
on
mite
occurrence
as
related
to
pruning
and
harvest,
the
only
field
activities
of
concern.

Grapefruit
harvest
is
rarely
completed
before
spring
bloom,
so
the
grower
must
decide
to
prune
at
the
preferred
time
(
cool
months)
and
sacrifice
part
of
the
unharvested
crop
or
wait
until
spring
flush
hardens
in
April
which
means
sacrificing
some
of
the
next
year's
crop.
Dicofol
would
still
be
available
for
use
during
the
early
post­
bloom
production
period
when
pruning
was
delayed
to
late
fall
and
winter.
State
experts
indicate
that
dicofol
would
be
used
as
the
first
miticidal
spray
when
no
field
activities
would
be
restricted
by
the
extended
REI.
(
Personal
communication
with
J.
French).
Dicofol
use
in
other
periods
would
conflict
with
field
activities,
harvest,
and
result
in
the
use
of
an
alternative
miticide
with
a
more
acceptable
REI.
Regardless,
there
are
sufficient
efficacious
alternatives
to
dicofol
for
use
in
the
other
production
periods
which
have
acceptable
8
REI's.
No
biological
impact
is
expected
by
extension
of
dicofol
REI's
for
Texas
grapefruit
as
growers
will
only
switch
the
timing
of
dicofol
application
in
their
IPM
program..

ECONOMIC
IMPACT
OF
INCREASED
REI'S
No
economic
impact
is
expected
as
dicofol
use
can
be
maintained
for
post­
bloom
application.
In
addition,
dicofol
is
only
recommended
to
be
used
once
annually
in
a
rotational
miticide
IPM
program.
No
changes
in
use
will
occur
other
than
a
shifting
of
dicofol
in
the
spray
schedule
indicating
no
change
in
miticide
application
economics.

CONCLUSIONS
There
will
be
no
biological
or
economic
impact
from
extension
of
the
REI's
for
dicofol
use
on
citrus.
Dicofol
can
still
be
effectively
used
during
the
normal
period
of
mite
outbreaks
with
no
adverse
impact
on
field
activities.

LITERATURE
CITED
Citrus
Fruits
2004
Summary.
September
2004.
USDA/
NASS
http://
usda.
mannlib.
cornell.
edu/
reports/
nassr/
fruit/
zcf­
bb/
cfrt0904.
pdf
2004
Florida
Citrus
Pest
Management
Guide:
Rust
Mites,
Spider
Mites,
and
Other
Phytophagous
Mites.
University
of
Florida­
IFAS
Extension.
http://
edis.
ifas.
ufl.
edu/
CG002
Crop
Knowledge
Master
­
Texas
citrus
mite.
Dept.
of
Entomology
­
University
of
Hawaii.
http://
www.
extento.
hawaii.
edu/
kbase/
crop/
Type/
e_
banksi.
htm
Citrus
red
mite.
UC
Pest
Management
Guidelines.
http://
www.
ipm.
ucdavis.
edu/
PMG/
r107400111.
html
Citrus
Red
Mite:
a
Potential
Damaging
Pest
of
Texas
Citrus.
1980.
Journal
Rio
Grande
Valley
Horticultural
Society,
Vol.
34.
http://
primera.
tamu.
edu/
kcchome/
pubs/
redmitedamage.
htm
Mites
on
Texas
Citrus.
JV
French.
Texas
Agricultural
Extension
Service.
http://
primera.
tamu.
edu/
kcchome/
pubs/
mitepublication.
htm
Citrus
Center
2004­
2005
Pest
Control
Guide
http://
primera.
tamu.
edu/
kcchome/
pubs/
sprayguide.
htm
Texas
Citrus
­
Mites:
Description
and
Biology.
Texas
Agricultural
Extension
Service.
http://
aggie­
horticulture.
tamu.
edu/
citrus/
12309.
htm
9
Agricultural
Chemical
Usage
­
2003
Fruit
Summary.
August
2004.
USDA/
NASS.
http://
usda.
mannlib.
cornell.
edu/
reports/
nassr/
other/
pcu­
bb/
agcf0804.
pdf
Agricultural
Chemical
Usage
­
2001
Fruit
Summary.
August
2002.
USDA/
NASS.
http://
usda.
mannlib.
cornell.
edu/
reports/
nassr/
other/
pcu­
bb/
agcf0802.
pdf
Agricultural
Chemical
Usage
­
1999
Fruit
Summary.
July
2000.
USDA/
NASS.
http://
usda.
mannlib.
cornell.
edu/
reports/
nassr/
other/
pcu­
bb/
agch0700.
pdf
Personal
communication
with
Dr.
J
Victor
French.
November
2004.
Texas
Agricultural
Extension
Service.
10
APPENDIX
A
Crop
Development
J
F
M
A
M
J
J
A
S
O
N
D
Post­
bloom
Summer
Late
Summer
­
Fall
Winter
Cultural
Practices
J
F
M
A
M
J
J
A
S
O
N
D
Harvest
Pruning
Pest
Management
Activities
J
F
M
A
M
J
J
A
S
O
N
D
Soil
Sampling
Scouting
Mitcide
Application
11
