UNITED
STATES
ENVIRONMENTAL
PROTECTION
AGENCY
WASHINGTON,
D.
C.
20460
May
22,
2006
OFFICE
OF
PREVENTION,
PESTICIDES
AND
TOXIC
SUBSTANCES
MEMORANDUM
SUBJECT:
Benefits
and
Cost
Analysis
of
PCNB
and
Alternatives
for
Use
on
Golf
Course
Turf
(
Tees,
Greens,
Fairways),
Cotton,
Potatoes,
Green
Beans,
and
Cole
Crops
(
Cabbage,
Brussels
Sprouts,
Cauliflower)
(
DP#
328903,
DP#
328904)

FROM:
Leonard
Yourman,
Plant
Pathologist
Biological
Analysis
Branch
Tara
Chandgoyal,
Plant
Pathologist
Biological
Analysis
Branch
David
Donaldson,
Economist
Economic
Analysis
Branch
THRU:
Arnet
Jones,
Chief
Biological
Analysis
Branch
Biological
and
Economic
Analysis
Division
(
7503P)

Tim
Kiely,
Acting
Chief
Economic
Analysis
Branch
Biological
and
Economic
Analysis
Division
(
7503P)

TO:
Jill
Bloom,
Chemical
Review
Manager
Special
Review
and
Reregistration
Division
(
7508P)

Product
Review
Panel
Date:
May
3,
2006
SUMMARY
The
Agency
has
identified
PCNB
(
quintozene)
and
its
metabolites
as
being
persistent
and
bioaccumulative
in
the
environment.
In
addition,
there
is
evidence
of
long­
range
transport
through
the
air
due
to
PCNB
volatility.
The
Agency
is
interested
in
identifying
alternatives
to
2
PCNB
that
promote
effective
disease
management
at
acceptable
monetary
costs,
without
the
environmental
burden
associated
with
PCNB
use.

As
part
of
the
reregistration
review
of
PCNB,
BEAD
conducted
an
assessment
for
the
benefits
and
costs
associated
with
PCNB
and
its
alternatives
for
uses
on
golf
course
turf
(
tees,
greens,
and
fairways),
cotton,
potatoes,
green
beans,
and
three
cole
crops
(
cabbage,
Brussels
sprouts,
and
cauliflower).
These
sites
were
identified
by
the
Agency
as
the
highest
usage
sites
for
PCNB
in
terms
of
percent
crop
treated
and
overall
amount
of
active
ingredient
(
a.
i.)
applied
(
according
to
EPA
proprietary
data
and
USDA­
National
Agricultural
Statistics
Service).
Although
adverse
environmental
effects
from
PCNB
use
may
be
associated
with
other
use
sites
(
including
peanuts,
peppers,
dry
beans,
onions,
ornamentals,
and
seed
treatments
of
several
crops),
the
crops
examined
in
this
assessment
were
considered
to
be
of
the
highest
priority
for
review.

Among
the
crop
sites
examined
in
this
assessment
(
golf
course
turf,
cotton,
potatoes,
green
beans,
and
cabbage,
Brussels
sprouts,
and
cauliflower),
BEAD
has
identified
effective
and
feasible
alternative
fungicides
for
treating
diseases
that
currently
can
be
treated
with
PCNB.
The
exception
to
this
is
the
use
of
PCNB
for
treating
clubroot
of
cabbage,
Brussels
sprouts,
and
cauliflower.
There
does
not
appear
to
be
a
chemical
alternative
to
PCNB
for
this
disease.
Cultural
practices,
such
as
a
seven
year
rotation
or
increase
of
soil
pH,
may
not
be
sufficient
or
feasible
alternatives
if
the
causal
pathogen
is
present
in
the
soil.
Otherwise,
for
the
crops
examined
in
this
assessment
(
except
for
clubroot
of
cole
crops),
all
crop
diseases
that
can
be
managed
with
PCNB
are
equally
effectively
managed
with
alternative
fungicides.

Resistance
management
problems
do
not
appear
to
be
of
concern
for
alternatives
to
PCNB.
Generally,
the
typical
once
per
season
application
of
fungicides
for
the
diseases
examined
in
this
assessment
reduces
the
likelihood
of
pathogen
resistance.
In
addition,
for
turf,
the
numerous
alternative
fungicides
that
are
available
have
different
modes
of
action
and
are
generally
tank
mixed
to
allay
pathogen
resistance.
In
fact,
there
are
reports
(
see
Johnston
and
Golob,
2003)
that
the
pink
snow
mold
pathogen
has
developed
resistance
to
PCNB
on
a
small
number
of
sites
with
long­
time
use
of
PCNB.

For
turf,
there
are
numerous
alternative
fungicides
that
are
highly
effective
and
economically
feasible.
For
pink
and
gray
snow
mold
treatment,
for
which
PCNB
is
most
commonly
used,
current
recommendations
from
extension
specialists,
based
on
years
of
research,
indicate
that
combinations
of
fungicides
are
more
effective
than
individual
products.
While
PCNB
has
been
a
mainstay
for
snow
mold
management,
there
are
currently
numerous
fungicides
available
(
including
azoxystrobin,
fludioxonil,
flutolanil,
trifloxystrobin,
propiconazole,
iprodione,
chlorothalonil),
with
different
modes
of
action,
that
golf
course
superintendents
can
rely
on
to
manage
these
diseases,
at
least
as
effectively
as
with
PCNB.
In
addition,
PCNB
is
known
to
cause
phytotoxicity
in
some
situations,
while
alternatives
have
not
caused
this
problem.

For
cotton,
Rhizoctonia
damping­
off
control
is
the
primary
disease
for
which
PCNB
is
used.
BEAD
assessed
results
of
26
fungicide
trials
conducted
in
several
locations
and
over
four
growing
seasons
and
identified
azoxystrobin
and
iprodione
as
having
at
least
comparable
efficacy
and
cost
to
PCNB.
3
For
potato,
PCNB
is
primarily
used
to
manage
Rhizoctonia
solani,
but
azoxystrobin
and
flutolanil
are
equally
effective.
In
some
locations,
PCNB
is
used
for
control
of
white
mold
of
potato,
but
boscalid,
fluazinam,
thiophanate­
methyl,
and
iprodione
are
equally
effective.
For
both
of
these
diseases,
there
are
effective
alternatives
to
PCNB
at
comparable
costs.

For
managing
wirestem
of
cole
crops,
azoxystrobin
is
an
effective
and
economical
alternative
to
PCNB
for
field
and
transplant
applications.
In
addition,
fluidioxonil
is
a
seed
treatment
that
is
effective
and
economically
feasible
for
controlling
wirestem
disease.
For
managing
clubroot
of
cole
crops,
PCNB
appears
to
be
the
only
available
chemical
treatment
that
is
feasible
for
effective
management
of
the
disease
where
the
pathogen
occurs
in
soil.
Cultural
practices
require
a
six
or
seven
year
rotation
in
non­
cruciferous
crops
and
may
not
be
a
practical
alternative
for
farmers
who
have
infested
acreage.

For
managing
white
mold
on
green
beans,
effective
and
economical
alternatives
are
boscalid,
azoxystrobin
or
pyraclostrobin,
dicloran,
iprodione,
and
thiophanate­
methyl.
For
Rhizoctonia
root
and
stem
rots
of
green
beans,
effective
and
economical
alternatives
to
PCNB
are
azoxystrobin
or
pyraclostrobin,
iprodione,
and
chlorothalonil.

GOLF
COURSE
TURF
(
Tees,
Greens,
and
Fairways)

PCNB
has
been
a
long­
time
treatment
primarily
for
pink
and
gray
snow
molds,
although
it
is
labeled
for
some
other
turfgrass
diseases
as
well 
dollar
spot,
brown
patch,
large
patch
of
Zoysia,
and
leaf
spot.
Use
of
PCNB
for
snow
mold
management
constitutes
the
highest
overall
usage
of
PCNB
in
the
U.
S.
(
EPA
proprietary
data
and
USDA­
NASS).
It
has
provided
reliable
snow
mold
management
options
for
golf
courses
troubled
by
these
diseases
and
it
is
relatively
inexpensive
(
Nelson,
2004).
Pathogen
resistance
to
PCNB
is
not
common,
but
has
been
observed
in
areas
that
have
had
high
disease
pressure
and
long­
time
use
of
PCNB
(
Johnston
and
Golob,
2003).
Phytotoxicity
resulting
from
PCNB
treatments
has
been
observed,
especially
when
used
at
high
rates
or
in
warm
weather
(
Johnston
and
Golob,
2003;
Schumann,
2003;
Schumann,
2002;
Vincelli,
2001).
Research
over
the
years
has
identified
alternatives
to
PCNB
and
field
trials
have
been
published
(
commonly
in
Fungicide
and
Nematicide
Tests)
defining
fungicide
programs
that
usually
include
two
or
three
fungicides
in
combination.

Diseases
The
major
diseases
for
which
PCNB
is
used
are
pink
snow
mold
(
Microdochium
patch,
Fusarium
patch),
caused
by
the
fungal
pathogen
Microdochium
nival
and
gray
snow
mold
(
also
called
Typhula
blight),
caused
by
the
fungi
Typhula
incarnata
and
T.
ishikariensis.
Snow
molds
occur
in
cool,
moist
conditions
of
alternating
snow
and
rain
(
Johnston
and
Golob,
2003;
Vincelli
and
Powell,
2006;
UI,
1997).

Other
diseases
for
which
PCNB
is
used
are
dollar
spot
(
Sclerotinia
homoeocarp),
brown
patch
(
Rhizoctonia
solani,
R.
zeae),
large
patch
of
Zoysia
(
R.
solani)
and
leaf
spot/
melting­
out
(
Bipolaris
spp.
and
Drechslera
spp.).
4
Fungicides
for
Disease
Management
For
both
pink
and
gray
snow
molds,
there
are
several
combinations
of
fungicides
that
can
provide
equal
or
better
efficacy
compared
to
fungicide
combinations
that
include
PCNB
(
usually
used
at
rates
less
than
the
16
lb
PCNB
per
acre
when
PCNB
is
used
alone).
In
additiion,
combinations
of
fungicides
without
PCNB
have
greater
efficacy
than
treatments
with
PCNB
used
alone
(
Johnston
and
Golob,
2003;
Schumann,
2003;
Gregos
and
Jung,
2003;
Li
et
al.,
2003;
Anderson
et
al.,
2003;
Schumann
et
al.,
2002).

Tests
conducted
on
established
golf
courses
by
golf
course
supervisors
in
five
locations
throughout
Massachusetts,
in
the
fall
of
2002,
found
effective
disease
control
with
various
combinations
of
fungicides,
with
and
without
PCNB
(
Schumann,
2003).
Based
on
trials
conducted
in
1995,
1996,
1999,
2000,
and
2001
(
Schumann,
2003)
several
effective
fungicide
combinations
were
identified
that
effectively
managed
snow
molds
(
Table
1).
The
fungicide
combinations
reported
by
Schumann
(
2003)
are
similar
to
results
reported
by
others
(
Johnston
and
Golob,
2003;
Gregos
and
Jung,
2003;
Li
et
al.,
2003;
Anderson
et
al.,
2003).
To
avoid
phytotoxicity
a
tank­
mix
of
iprodione
and
chlorothalonil
was
considered
as
effective
as
PCNB
for
snow
mold
management
(
Vincelli,
2006).
5
Table
1.
Fungicide
combinations
and
recommended
rates
of
products
that
offer
winter­
long
protection
from
pink
snow
mold
and
gray
snow
mold
without,
and
with,
PCNBa
Active
ingredient(
s)
Product
name
(
rates
per
1000
ft2)
b
Fungicide
Treatment
Without
PCNB
Propiconazole
+
Chlorothalonil
Banner
Maxx
(
3
fl
oz)
+
Daconil
4F
(
8
fl
oz)
Propiconazole
+
Fludioxonil
Banner
Maxx
(
3­
4
fl
oz)
+
Medallion
50WP
(
0.5
oz)
Propiconazole
+
Fludioxonil
+
Chlorothalonil
Banner
Maxx
(
3­
4
fl
oz)
+
Medallion
50WP
(
0.5
oz)
+
Daconil
WS
6F
(
5.5
fl
oz)
Propiconazole
+
Flutolanil
Banner
MAXX
(
4
fl
oz)
+
ProStar
70WP
(
4
or
6
oz)
Propiconazole
+
Trifloxystrobin
Banner
MAXX
(
2
fl
oz)
+
Compass
50WG
(
0.2
oz)
Triadimefon
+
Flutolanil
Bayleton
50WP
(
6
oz)
+
ProStar
70WP
(
4
oz)
Triadimefon
+
Trifloxystrobin
Bayleton
50WP
(
2
oz)
+
Compass
50WG
(
0.25
oz)
Iprodione
+
Chlorothalonil
Chipco
26019FLO
2F
(
4
fl
oz)
+
Daconil
2787
4F
(
8
fl
oz)
Iprodione
+
Chlorothalonil
Chipco
26019FLO
2F
(
4
fl
oz)
+
Daconil
Weather
Stik
6F
(
5.5
fl
oz)
Iprodione
+
Chlorothalonil
Chipco
26GT
2SC(
4
fl
oz)
+
Daconil
Weather
Stik
6F
(
5.5
fl
oz)
Azoxystrobin
+
Propiconazole
Heritage
50WDG
(
0.4
oz)
+
Banner
MAXX
(
3
or
4
fl
oz)
Azoxystrobin
+
Propiconazole
+
Chlorothalonil
Heritage
50WDG
(
0.4
oz)
+
Banner
MAXX
(
2
fl
oz)
+
Daconil
Weather
Stik
6F
(
5.5
fl
oz)
Azoxystrobin
+
Iprodione
Heritage
50WG
(
0.4
oz)
+
Chipco
26GT
2SC
(
8
fl
oz)
Azoxystrobin
+
Chlorothalonil
Heritage
50WG
(
0.4
oz)
+
Daconil
Weatherstik
6F
(
8.0
fl
oz)
Azoxystrobin
+
Chlorothalonil
Heritage
50WG
(
0.4
oz)
+
Daconil
Ultrex
82.5WDG
(
3.2,
5,
or
7.5
oz)
Fludioxonil
+
Chlorothalonil
Medallion
50WP
(
0.5
oz)
+
Daconil
Weather
Stik
6F
(
5.5
fl
oz)
(
Thiophanate­
methyl
+
chlorothalonil)
Spectro
Thiophanate­
methyl
Topsin
M
Fungicide
Treatment
With
PCNBc
Propiconazole
+
PCNB
Banner
MAXX
1.24MEC
(
3
fl
oz)
+
Turfcide
400
(
9
fl
oz)
Triademefon
+
PCNB
Bayleton
50WP
(
2
oz)
+
Turfcide
400
(
10
fl
oz)
Triadimefon
+
Trifloxystrobin
+
PCNB
Bayleton
50WP
(
2
oz)
+
Compass
50WG
(
0.25
oz)
+
Turfcide
400
(
6
fl
oz)
Iprodione
+
Chlorothalonil
+
PCNB
Chipco
26GT
2SC
(
4
fl
oz)
+
Daconil
Weather
Stik
6F
(
5.5
fl
oz)
+
Turfcide
400
(
8
fl
oz)
Chlorothalonil
+
PCNB
Daconil
Weather
Stik
6F
(
5.5
fl
oz)
+
Turfcide
400
(
8
fl
oz)
Chlorothalonil
+
PCNB
Daconil
Ultrex
82.5WDG
(
3.7
oz)
+
Turfcide
400
(
9
fl
oz)
Chlorothalonil
+
PCNB
Daconil
Ultrex
82.5WDG
(
3.5
oz)
+
Turfcide
400
(
8
fl
oz)
Azoxystrobin
+
PCNB
Heritage
50WG
(
0.4
oz)
+
Turfcide
(
6
fl
oz)
Flutolanil
+
PCNB
ProStar
70WP
(
4
oz)
+
Turfcide
400
(
6
fl
oz)
(
Thiophanate­
methyl
+
chlorothalonil)
+
PCNB
Spectro
+
Defend
PCNB
Used
Alone
PCNB
Defend
75
WP
(
8
oz)
(=
0.375
lb
PCNB
per
1000
ft2,
or
16.335
lb/
acre)
a
Based
on
results
from
trials
conducted
in
1995,
1996,
1999,
2000,
and
2001
(
Schumann,
2003).
b
Pesticide
application
rates
for
turf
are
typically
calculated
for
1000
square
feet,
rather
than
on
a
per­
acre
basis.
Multiply
by
43.56
to
calculate
rate
per
acre.
Rates
shown
are
amount
of
product,
not
a.
i.
Since
percent
of
a.
i.
in
individual
products
vary,
comparison
of
product
amount
requires
calculating
amount
of
a.
i.
for
each
product.
c
PCNB
in
combination
with
other
fungicides
is
typically
used
at
rates
<
12
fl
oz
of
product,
which
is
equal
to
<
0.375
lb
PCNB/
1000
ft2
(=
16.335
lb
per
acre),
based
on
4
lb
PCNB
per
gallon
of
product.
6
For
treatment
of
diseases
that
may
be
treated
with
PCNB
there
are
effective
alternatives
determined
by
extensive
fungicide
trials
over
several
years.
Based
on
performances
of
fungicides
from
672
reports
in
Fungicide
and
Nematicide
Tests,
Vincelli
(
2006)
rated
the
efficacy
of
(
mostly)
individual
fungicides
for
turf
diseases
in
a
University
of
Kentucky
extension
publication,
Chemical
Control
of
Turfgrass
Diseases,
2006.
While
combinations
of
fungicides
are
frequently
recommended
(
see
Schumann,
2003),
these
ratings
provide
an
insight
into
comparative
efficacy.
Efficacy
ratings
were
"++++"
=
excellent,
"+++"=
good
to
excellent,
"++"=
fair
to
good;
ratings
followed
by
"
½
"
were
intermediate
between
two
categories.
Alternatives
were
available
for
PCNB
for
all
of
the
diseases.

For
pink
snow
mold,
fludioxonil
was
rated
"++++",
iprodione
+
chlorothalonil
was
rated
"+++
½
"
(
as
was
PCNB),
and
several
fungicides
were
rated
"+++"
(
iprodione,
propiconazole,
pyraclostrobin,
thiophanate­
methyl,
trifloxystrobin).

Vincelli
states
that
"
PCNB
has
proven
to
be
an
outstanding
fungicide
for
controlling
pink
snow
mold 
However,
application
of
PCNB
has
been
shown
to
cause
notable
phytotoxicity
to
certain
cultivars
of
creeping
bentgrass
and
to
Poa
annua
under
some
conditions.
Superintendents
can
expect
a
similar
level
of
disease
control
without
the
risk
of
phytotoxicity
from
a
mixture
of
iprodione
and
chlorothalonil,
each
at
their
labeled
rates.
Indeed,
the
tank­
mix
often
provides
a
greater
level
of
disease
control
than
either
product
alone."
See
Table
1
for
effective
fungicide
combinations
for
managing
pink
(
and
gray)
snow
mold.

For
gray
snow
mold,
Vincelli
states
that
"
although
gray
snow
mold
is
rarely
a
problem
in
Kentucky,
this
mixture
[
iprodione
+
chlorothalonil]
also
controls
that
disease,
should
it
occur."

For
brown
patch,
there
were
several
fungicides
available
that
were
rated
"++++"
(
e.
g.,
azoxystrobin,
pyraclostrobin,
trifloxystrobin),
"+++
½
"
(
fludioxonil,
flutolanil,
polyoxin
D),
or
"+++"
(
chlorothalonil,
iprodione);
PCNB
was
rated
"++".

For
dollar
spot
management,
PCNB
was
not
included
in
trials
to
a
sufficient
extent
to
receive
an
efficacy
rating,
but
boscalid,
myclobutanil,
propiconazole,
thiophanate­
methy,
and
triadimefon
were
rated
"++++".
Iprodione
was
rated
"+++
½
"
,
and
chlorothalonil
and
fenarimol
were
rated
"+++".

For
large
patch
of
Zoysia,
which
affects
Bermudagrass
as
well
as
Zoysia,
azoxystrobin,
flutolanil,
and
triadimefon
were
rated
"++++",
as
was
PCNB.

For
leaf
spot/
melting­
out
(
Bipolaris
spp.
and
Drechslera
spp.)
iprodione
was
rated
"++++"
and
azoxystrobin
was
rated
"+++
½
"
.
Chlorothalonil
was
rated
"++
½
"
and
PCNB
was
rated
"++".

PCNB
Use
on
Golf
Course
Turf
Approximately
500,000
lbs
of
PCNB
are
applied
to
turf
per
year
with
application
occurring
predominantly
in
northern
states
(
EPA
Proprietary
Data).
Though
PCNB
targets
several
pests,
the
majority
of
PCNB
is
applied
to
turf
for
control
of
snow
mold.
Table
2
shows
the
top
ten
states
where
PCNB
is
used.
7
Table
2.
Leading
States
where
PCNB
is
used
on
golf
course
turf
State
Percent
of
Total
U.
S
Golf
Courses
that
Apply
PCNB
Michigan
11%
New
York
9%
California
8%
Wisconsin
7%
Washington
7%
Minnesota
7%
Ohio
7%
Colorado
5%
Pennsylvania
4%
Oregon
4%
Source:
EPA
Proprietary
Data.

Costs
of
PCNB
and
Alternatives,
and
Golf
Course
Level
Impacts
The
following
focuses
on
the
costs
of
PCNB
alternatives
that
have
been
identified
as
providing
equal
or
better
control
of
the
major
pests
controlled
by
PCNB
and
provides
a
summary
of
increased
costs
that
might
result
from
changing
to
these
alternatives.
The
Agency's
understanding
of
impacts
to
golf
courses
currently
using
PCNB
is
then
provided.
The
primary
focus
of
our
analysis
is
on
the
control
of
snow
mold,
but
many
of
the
same
pesticide
products
are
used
widely
to
control
brown
patch,
dollar
spot,
large
patch
of
Zoysia,
and
leaf
spot/
melting­
out.
Given
that
the
control
of
these
pests
are
relatively
similar
in
cost
to
snow
mold
control,
the
conclusions
drawn
for
snow
mold
control
will
apply
generally
to
all
PCNB
use
sites.

PCNB
and
other
fungicides
used
for
snow
mold
control
are
most
effective
when
applied
concurrently
with
other
fungicide
active
ingredients.
For
this
reason,
the
most
informative
measure
available
to
compare
the
costs
of
PCNB
and
its
alternatives
is
the
cost
of
tank­
mixes
of
fungicides
containing
active
ingredients
that
provide
snow
mold
control.
Table
3
shows
pesticide
costs,
with
and
without
PCNB,
for
selected
tank
mixes
that
provide
effective
snow
mold
control
(
see
Table
1).
8
Table
3.
Cost
of
pesticide
combinations
for
snow
molds.
Active
Ingredient
Tank
Mix
and
use
rate
per
1,000
square
feet
Cost
per
1,000
Square
Feeta
Propiconazole
+
Fludioxonil
Banner
Maxx
(
3­
4
fl
oz)
+
Medallion
50WP
(
0.5
oz)
$
17.70
Propiconazole
+
Fludioxonil
+
Chlorothalonil
Banner
Maxx
(
3­
4
fl
oz)
+
Medallion
50WP
(
0.5
oz)
+
Daconil
WS
6F
(
5.5
fl
oz)
$
21.20
Propiconazole
+
Flutolonil
Banner
MAXX
(
4
fl
oz)
+
ProStar
70WP
(
4
or
6
oz)
$
26.05
Propiconazole
+
Trifloxystrobin
Banner
MAXX
(
2
fl
oz)
+
Compass
50WG
(
0.2
oz)
$
9.95
Triadimefon
+
Flutolonil
Bayleton
50WP
(
6
oz)
+
ProStar
70WP
(
4
oz)
$
40.60
Triadimefon
+
Trifloxystrobin
Bayleton
50WP
(
2
oz)
+
Compass
50WG
(
0.25
oz)
$
15.25
Iprodione
+
Chlorothalonil
Chipco
26019FLO
2F
(
4
fl
oz)
+
Daconil
2787
4F
(
8
fl
oz)
$
9.95
Iprodione
+
Chlorothalonil
Chipco
26019FLO
2F
(
4
fl
oz)
+
Daconil
Weather
Stik
6F
(
5.5
fl
oz)
$
7.85
Azoxystrobin
+
Propiconazole
Heritage
50WDG
(
0.4
oz)
+
Banner
MAXX
(
3
or
4
fl
oz)
$
20.20
Azoxystrobin
+
Propiconazole
+
Chlorothalonil
Heritage
50WDG
(
0.4
oz)
+
Banner
MAXX
(
2
fl
oz)
+
Daconil
Weather
Stik
6F
(
5.5
fl
oz)
$
19.75
Azoxystrobin
+
Iprodione
Heritage
50WG
(
0.4
oz)
+
Chipco
26GT
2SC
(
8
fl
oz)
$
19.65
Azoxystrobin
+
Chlorothalonil
Heritage
50WG
(
0.4
oz)
+
Daconil
Weatherstik
6F
(
8.0
fl
oz)
$
16.10
Azoxystrobin
+
Chlorothalonil
Heritage
50WG
(
0.4
oz)
+
Daconil
Ultrex
82.5WDG
(
7.5
oz)
$
16.30
Fludioxonil
+
Chlorothalonil
Medallion
50WP
(
0.5
oz)
+
Daconil
WeatherStik
6F
(
5.5
fl
oz)
$
12.00
Propiconazole
+
PCNB
Banner
MAXX
1.24MEC
(
3
fl
oz)
+
Turfcide
400
(
9
fl
oz)
$
11.30
Triademefon
+
PCNB
Bayleton
50WP
(
2
oz)
+
Turfcide
400
(
10
fl
oz)
$
13.15
Triadimefon
+
Trifloxystrobin
+
PCNB
Bayleton
50WP
(
2
oz)
+
Compass
50WG
(
0.25
oz)
+
Turfcide
400
(
6
fl
oz)
$
17.50
Iprodione
+
Chlorothalonil
+
PCNB
Chipco
26GT
2SC
(
4
fl
oz)
+
Daconil
Weather
Stik
6F
(
5.5
fl
oz)
+
Turfcide
400
(
8
fl
oz)
$
10.85
Chlorothalonil
+
PCNB
Daconil
Weather
Stik
6F
(
5.5
fl
oz)
+
Turfcide
400
(
8
fl
oz)
$
6.55
Chlorothalonil
+
PCNB
Daconil
Ultrex
82.5WDG
(
3.7
oz)
+
Turfcide
400
(
9
fl
oz)
$
6.00
Chlorothalonil
+
PCNB
Daconil
Ultrex
82.5WDG
(
3.5
oz)
+
Turfcide
400
(
8
fl
oz)
$
5.50
Azoxystrobin
+
PCNB
Heritage
50WG
(
0.4
oz)
+
Turfcide
(
6
fl
oz)
$
13.25
Flutolonil
+
PCNB
ProStar
70WP
(
4
oz)
+
Turfcide
400
(
6
fl
oz)
$
14.75
Source:
Cost
data
taken
from
EPA
Proprietary
Data.
Rate
information
from
Table
1.
a
Pesticide
application
rates
for
turf
are
typically
calculated
for
1000
square
feet,
rather
than
on
a
per­
acre
basis.
Multiply
by
43.56
to
calculate
rate
per
acre.
Rates
shown
are
amount
of
product,
not
a.
i.
Since
percent
of
a.
i.
in
individual
products
vary,
comparison
of
product
amount
requires
calculating
amount
of
a.
i.
for
each
product.

When
adjusted
for
typical
tank­
mix
fungicide
combinations
and
use
rates
typical
of
snow
mold
control,
the
predominant
PCNB
use
site,
tank­
mixes
containing
PCNB
range
in
cost
from
$
5.50
to
$
17.50,
and
alternatives
that
do
not
contain
PCNB
range
in
cost
from
$
7.85
to
$
40.60.
The
cost
of
PCNB
application
is
similar
to
many
of
the
alternatives,
though
at
the
upper
end
of
the
cost
range,
alternatives
are
significantly
more
expensive.

Maintaining
high­
quality
playing
surfaces
is
important
for
the
golf
industry's
economic
viability.
However,
the
Agency
does
not,
at
present,
have
the
necessary
information
to
gauge
the
impacts
of
costs
increases
on
representative
golf
courses
or
the
golf
industry.
For
this
reason,
our
analysis
of
the
economic
impact
of
switching
from
PCNB
to
a
PCNB
alternative
can
not
explicitly
consider
the
direct
impacts
to
golf
course
economic
viability.
Nonetheless,
given
that
there
are
PCNB
alternatives
available
that
provide
equal
or
better
snow
mold
control
at
a
9
comparable
cost,
we
anticipate
that
switching
from
PCNB
to
its
alternatives
will
not
significantly
reduce
the
economic
viability
of
golf
courses
using
PCNB.

Conclusion
BEAD
has
identified
several
effective
fungicides
that
are
alternatives
to
PCNB
for
managing
pink
and
gray
snow
molds
on
tees,
greens,
and
fairways
of
golf
courses.
Effective
fungicide
treatments
without
PCNB
have
been
identified
through
numerous
studies
and
are
comprised
of
tank­
mixes
of
two
or
three
fungicides
of
different
chemistries.
While
PCNB
can
be
an
effective
component
of
tank­
mixes
to
manage
snow
molds,
other
fungicides
for
tank­
mixing
are
available
to
golf
course
managers
to
manage
these
diseases
as
effectively
as
PCNB,
and
in
several
cases,
more
effectively
than
when
PCNB
is
used.
In
addition,
use
of
alternatives
avoids
the
phytotoxic
effects
experienced
in
some
turf
cultivars
(
Vincelli,
2006).

While
successful
disease
management
can
be
more
difficult
on
tees
and
greens
due
to
the
intensively
managed
nature
of
these
areas,
there
are
several
very
effective
fungicide
alternatives
to
PCNB
available
to
golf
course
superintendents
for
tees,
greens,
as
well
as
fairways.
In
addition,
there
are
effective
fungicides
available
for
the
successful
management
of
brown
patch,
dollar
spot,
large
patch
of
Zoysia,
and
leaf
spot.
PCNB
has
been
widely
used
because
of
relatively
low
costs.
Several
of
the
available
PCNB
alternatives
are
of
a
substantially
higher
cost
than
many
combination
products
containing
PCNB.
However,
there
are
also
several
alternatives
that
will
result
in
similar
or
moderately
higher
costs
than
PCNB,
and
potentially
provide
more
effective
control
and
lower
risk
of
turf
damage
due
to
phytoxicity.
Given
data
limitations,
we
were
unable
to
directly
evaluate
the
impact
of
possible
pesticide
cost
increases
to
the
economic
viability
of
golf
courses.
However,
based
on
our
evaluation
of
treatment
costs
and
our
finding
that
there
are
numerous
available
and
similarly
priced
effective
alternatives,
we
anticipate
that
if
PCNB
is
no
longer
available,
golf
courses
that
currently
use
PCNB
would
not
experience
substantial
negative
impacts.

References
for
Golf
Course
Turf
Anderson,
M.
A.,
Ross,
R.
B.,
and
Tompkins,
D.
K.
2003.
Fungicidal
control
of
overwintering
diseases
in
eastern
British
Columbia,
Canada,
2001­
2002.
Fungicide
and
Nematicide
Tests
58:
T059.

Gregos,
J.
and
Jung,
G.
2003.
Evaluation
of
fungicides
for
the
control
of
pink
snow
mold
and
Typhula
light
in
annual
bluegrass,
2001­
2002.
Fungicide
and
Nematicide
Tests
58:
T019.

Johnston,
W.
J.
and
Golob,
C.
T.
2003.
Snow
mold
control
in
the
intermountain
northwest.
USGA
[
United
States
Golf
Association]
Turfgrass
and
Environmental
Research
Online
2
(
23):
1­
9.
http://
usgatero.
msu.
edu/
v02/
n23.
pdf
Li,
D.,
Ross,
J.
B.,
and
Tompkins,
D.
K.
2003.
Snow
mold
control
trials
on
creeping
bentgrass
in
eastern
British
Columia,
Canada,
2000­
2001.
Fungicide
and
Nematicide
Tests
58:
T058.
10
Nelson,
M.
2004.
Carving
an
edge
in
snow
mold.
United
States
Golf
Association
Green
Section
Record.
March/
April
(
2004).
http://
turf.
lib.
msu.
edu/
2000s/
2004/
040306.
pdf
Schumann,
G.
2003.
UMass
snow
mold
fungicide
trial
results
and
real
world
results
from
superintendents
2002­
2003.
University
of
Massachusetts
Extension.
http://
www.
umassturf.
org/
publications/
online_
pubs/
snow_
mold_
summary_
03.
pdf
Schumann,
G.
L.,
Anair,
R.,
and
Ebdon,
J.
S.
2002.
Evaluation
of
fungicides
and
application
timing
for
preventive
control
of
snow
mold
on
creeping
bentgrass,
2000­
2001.
Fungicide
and
Nematicide
Tests
57:
T19.

UI
(
University
of
Illinois).
1997.
Reports
on
Plant
Diseases:
Snow
molds
of
turfgrasses.
RPD­
404,
UI
Extension
IPM.
http://
www.
ipm.
uiuc.
edu/
diseases/
series400/
rpd404/
index.
html
Vincelli,
P.
and
Powell,
A.
J.
2006.
Chemical
control
of
turfgrass
diseases
2006.
University
of
Kentucky
Extension
Service.
http://
www.
ca.
uky.
edu/
agc/
pubs/
ppa/
ppa1/
ppa1.
pdf
Vincelli,
P.
2001.
More
on
phytotoxicity
risk
with
PCNB.
Kentucky
Pest
News,
U.
KY
Extension.
Dec.
10,
2001,
number
938.
http://
www.
uky.
edu/
Ag/
kpn/
kpn_
01/
pn011210.
htm#
lawmor.

COTTON
A
total
of
400,000
lb
of
PCNB
were
applied
in­
furrow
to
cotton
on
4%
of
the
total
acres
in
the
U.
S.
(
USDA­
NASS,
1998­
2001,
2003).
It
is
most
commonly
used
as
an
in­
furrow
treatment
applied
to
the
soil
as
the
planter
is
dropping
seed.
Azoxystrobin,
iprodione,
and
PCNB
are
the
three
fungicides
available
for
in­
furrow
treatments
for
control
of
Rhizoctonia
seedling
disease.
Fungicide
resistance
has
not
occurred
for
Rhizoctonia
damping­
off
of
cotton
and
Rhizoctonia
spp.
are
generally
considered
of
low
risk
of
developing
resistance
to
fungicides
(
FRAC,
2005).
Therefore,
fungicide
efficacy
is
the
main
concern
for
farmers
in
attempting
to
manage
this
disease.

Rhizoctonia
Seedling
Disease
PCNB
has
been
used
to
manage
Rhizoctonia
seedling
disease,
which
is
a
post­
emergence
damping­
off
disease
caused
by
Rhizoctonia
solani.
It
can
be
a
problem
for
cotton
growers
in
some
locations,
especially
in
the
south
(
UG,
2006;
Mueller,
1996).
This
disease
is
primarily
a
problem
when
planting
takes
place
in
cool
and
wet
weather
and,
therefore,
may
occur
only
in
localized
growing
areas.
Crop
rotation
might
reduce
populations
of
pathogens,
and
other
cultural
practices,
such
as
a
well­
prepared
seedbed,
which
can
help
create
optimal
soil
temperatures
for
planting
to
improve
crop
stands
(
UT,
2005).
However,
common
soil
pathogens
can
infest
rotation
crops
such
as
corn,
peanut,
and
soybeans
and
growers
usually
rely
on
fungicide
seed
treatment
and
where
needed,
in­
furrow
fungicide
treatments
(
Mueller,
1996).
11
Planting
treated
seed
in
optimal
conditions
greatly
reduces
the
incidence
of
seedling
diseases
(
UG,
2006).
Warmer
temperatures
and
soils
greatly
increase
germination
and
seedling
emergence
and
reduce
damping­
off
incidences.
In
North
Carolina,
it
was
estimated
that
5%
losses
occur
in
cotton
due
to
the
combined
effects
of
various
damping­
off
diseases,
including
Rhizoctonia
damping­
off
(
Koenning,
2004).

Fungicides
for
Rhizoctonia
Management
Seed
treatment.
Fungicide
seed
treatment
is
standard
practice
for
cotton
seed,
and
can
help
to
reduce
the
incidences
of
damping­
off
diseases.
Nearly
all
commercial
cotton
seed
sold
for
planting
is
treated
with
fungicides
to
help
manage
damping­
off
diseases
(
Mueller,
1996).
Several
effective
fungicides
are
available
for
cotton
seed
treatment
for
control
of
Rhizoctonia
damping­
off,
including
carboxin
(
Vitavax
®
)
,
carboxin
+
PCNB,
triadimenol
(
Baytan
®
)
,
triadimenol
+
thiram,
2­(
thiocyanomethylthio)
benzothiazole
(
Argent
®
)
,
chloroneb
(
Nuflow
®
M),
fludioxonil
(
Maxim
®
)
,
and
azoxystrobin
(
Protégé
®
)
(
TAMU,
2005).
In
fungicide
trials
in
Texas,
"
all
fungicide
treatments
performed
similarly
and
better
than
the
seed
without
fungicide
protection"
(
TAMU,
2005).

In­
furrow
treatment.
Much
research
has
been
conducted
on
cotton
to
identify
alternatives
to
PCNB
for
in­
furrow
treatment
of
Rhizoctonia
damping­
off.
BEAD
reviewed
results
of
the
26
infurrow
fungicide
trials
(
Table
4)
published
in
Fungicide
and
Nematicide
Tests
from
2001
to
2005
(
see
reference
list
for
cotton,
below)
that
compared
the
efficacy
of
azoxystrobin,
iprodione,
and
PCNB
against
Rhizoctonia
damping­
off.
These
26
trials
showed
that
azoxystrobin,
iprodione,
or
both
were
at
least
as
effective
as
PCNB
in
managing
Rhizoctonia
damping­
off
in­
furrow
based
on
seedling
stand,
skip
index,
and
yield
(
measured
by
either
seed
cotton
or
lint).

In­
furrow
treatments
involve
application
of
a
fungicide
or
tank
mix
of
fungicides
into
the
seed
furrow
while
planting
seed,
followed
by
covering
the
seed
with
the
treated
soil.
Depending
on
disease
pressure
and
location,
costs
and
benefits
of
in­
furrow
treatments
are
calculated
by
farmers
before
planting.
"
As
significant
yield
losses
to
seedling
disease
are
sporadic
in
Georgia,
the
Cooperative
Extension
Service
does
not
recognize
the
need
for
an
additional
fungicide
treatment
for
each
and
every
cotton
field"
(
UG,
2006).
Research
in
Texas
(
TAMU,
1996),
the
largest
cotton
growing
state,
suggests
that
the
cost
of
in­
furrow
fungicide
treatment
must
be
weighed
with
the
likelihood
of
damping­
off
disease
for
the
expense
to
be
warranted.
"
Cost
of
infurrows
is
generally
higher,
in
the
$
10.00
per
acre
range,
compared
to
approximately
$
2.00
per
acre
for
two
of
the
better
seed
treatments
in
combination.
In­
furrows
also
have
not
outperformed
the
better
seed
treatments
in
tests
on
the
High
Plains"
(
TAMU,
1996).
Where
high
disease
pressure
is
present
(
frequently
in
wet
locations),
in­
furrow
applications
of
fungicides
appear
to
be
useful
(
UT,
2005).

For
the
fungicides
available
to
treat
Rhizoctonia
damping­
off,
azoxystrobin
is
typically
used
at
rates
ranging
from
0.08
to
0.12
lb
per
acre.
Iprodione
is
typically
used
at
rates
ranging
from
0.16
to
0.20
lb
per
acre.
PCNB
is
used
at
rates
ranging
from
1.0
to
1.5
lb
per
acre,
with
a
season
maximum
of
2.0
lb
per
acre.
12
A
product
(
Messenger
®
,
EPA
reg.
no.
69834­
2)
containing
3%
harpin
protein
was
an
in­
furrow
treatment
in
six
of
the
trials
reviewed
(
McLean
et
al.,
2002a,
2002b,
2002d,
2002g,
2003a,
2003b).
Results
appeared
promising,
although
the
label
does
not
include
recommendations
for
in­
furrow
application.
In
addition,
water
used
for
dilution
has
to
be
of
such
quality
(
e.
g.,
chlorine
content,
salts)
not
to
de­
activate
the
product.
Further
testing
may
help
define
this
product's
usefulness
for
managing
Rhizoctonia
damping­
off.

Table
4.
Comparison
of
efficacya
against
Rhizoctonia
and
other
damping­
off
diseases
with
azoxystrobin
(
A),
iprodione
(
I),
and
PCNB
(
P)
for
in­
furrow
application
in
cotton
based
on
plant
stand,
gaps
in
planted
rows,
and
yield.
Number
Plant
standb
Skip
indexc
Yieldd
(
lb/
Acre)
Fungicide
trial
citation
1
(
Ae=
If)
>
Pg
Not
tested
Not
tested
Colyer
and
Vernon,
2003
2
A=
I=
P
Not
tested
Not
tested
Colyer
and
Vernon,
2004a
3
A=
I=
P
Not
tested
Not
tested
Colyer
and
Vernon,
2004b
4
(
A=
P)
>
I
A=
I=
P
A=
I=
P
(
seed
cotton)
Lawrence
et
al.,
2004a
5
A=
I=
P
A=
I=
P
A=
I=
P
(
seed
cotton)
Lawrence
et
al.,
2004b
6
(
A=
P)
>
I
A=
I=
P
A=
I=
P
(
seed
cotton)
McLean
et
al.,
2001
7
A=
I=
P
A=
I=
P
A=
I=
P
(
seed
cotton)
McLean
et
al.,
2002a
8
(
A=
P)
>
I
(
A=
P)
>
I
A=
I=
P
(
seed
cotton)
McLean
et
al.,
2002b
9
A=
I=
P
A=
I=
P
I
>
(
A=
P)
(
seed
cotton)
McLean
et
al.,
2002c
10
A=
I=
P
A=
I=
P
A=
I=
P
(
seed
cotton)
McLean
et
al.,
2002d
11
A=
I=
P
A=
I=
P
I
>
(
A=
P)
(
seed
cotton)
McLean
et
al.,
2002e
12
A=
I=
P
A=
I=
P
A=
I=
P
(
seed
cotton)
McLean
et
al.,
2002f
13
(
A=
P)
>
I
(
A=
P)
>
(
A=
I)
(
A=
P)
>
I
(
seed
cotton)
McLean
et
al.,
2002g
14
A=
I=
P
A=
I=
P
(
A=
P)
>
(
P=
I)
(
seed
cotton)
McLean
et
al.,
2003a
15
A=
I=
P
A=
I=
P
I
>
(
A=
P)
(
seed
cotton)
McLean
et
al.,
2003b
16
(
A=
P)
>
I
(
A=
P)
>
I
(
A=
P)
>
I
(
seed
cotton)
McLean
et
al.,
2003c
17
A=
I=
P
A=
I=
P
(
A=
I)
>
P
(
seed
cotton)
McLean
et
al.,
2003d
18
A=
I=
P)
Not
tested
A=
I=
P
(
lint)
Padgett
and
Price,
2001
19
A=
I=
P
Not
tested
A=
I=
P
(
lint)
Padgett
and
Price,
2002
20
(
A=
P)
>
I
Not
tested
A=
I=
P
(
lint)
Padgett
and
Price,
2003
21h
A=
P
Not
tested
A=
P
(
seed
cotton)
Padgett
and
Price,
2004
22h
A=
P
Not
tested
A=
P
(
lint)
Phipps
and
Maitland,
2002
23i
I=
P
Not
tested
I=
P
(
lint)
Phipps,
2004
24h
A
>
P
Not
tested
A
>
P
(
lint)
Phipps
and
Rideout,
2005a
25
A
>
I
>
P
Not
tested
A
>
I
>
P
(
lint)
Phipps
and
Rideout,
2005b
26
(
A=
I)
>
(
I=
P)
A=
I=
P
A
>
(
I=
P)
(
seed
cotton)
Seebold
and
Horten,
2003
a
Efficacy
ratings
are
based
on
findings
of
statistical
significance
provided
in
the
results
reported
in
Fungicide
and
Nematicide
(
F&
N)
Tests
(
see
References
for
Cotton
section,
below).
b
Number
of
plants
in
a
defined
row
length 
scale
varies
according
to
the
trial.
c
Gaps
within
a
row 
scale
varies
according
to
the
trial.
d
Based
on
yield
of
cotton
seed
or
lint
as
specified
(
in
parentheses)
for
individual
fungicide
trials.
e
Azoxystrobin
f
Iprodione
g
PCNB
h
Iprodione
was
not
included
in
this
trial.
i
Azoxystrobin
was
not
included
in
this
trial.

U.
S.
Cotton
Production
Cotton
is
a
major
crop
in
the
United
States,
with
a
total
annual
value
of
production
averaging
over
$
4.5
billion
(
see
Table
5).
There
are
two
varieties
of
cotton
grown
in
the
U.
S.
Upland
13
cotton
is
grown
predominantly
from
Texas
in
the
west,
throughout
the
southeast
to
the
Atlantic
Coast,
extending
as
far
north
as
Kansas
and
Missouri.
Pima
cotton
is
a
higher
value,
longer
staple
cotton
grown
in
California,
Texas,
Arizona,
and
New
Mexico.
Table
5
shows
the
area
harvested,
production,
and
the
value
of
production
by
state
for
both
types
of
cotton,
averaged
over
the
years
2001
 
2005.

Table
5.
Cotton
are
harvested,
production
and
value:
2001­
2005
(
average).
State
Area
Harvested
1,000
Acres
Production
1,000
Bales*
Value
of
Production
1,000
Dollars
Texas
4,810
5,955
1,221,090
Georgia
1,324
1,971
431,468
Mississippi
1,228
2,191
451,680
Arkansas
974
1,917
410,207
North
Carolina
838
1,261
267,356
California
734
2,088
677,228
Louisiana
590
961
204,751
Tennessee
567
958
201,810
Alabama
548
795
167,303
Missouri
395
744
156,329
Arizona
242
649
148,033
South
Carolina
239
338
73,504
Oklahoma
195
258
54,325
Florida
101
122
27,058
Virginia
92
152
30,906
Kansas
66
71
15,841
New
Mexico
62
114
29,828
United
States
13,003
20,547
4,568,718
Source:
United
States
Department
of
Agriculture,
National
Agricultural
Statistics
Service:
Crop
Production
2003
Summary,
Crop
Production
2005
Summary,
Crop
Values
2003
Summary,
Crop
Values
2005
Summary.
*
A
standard
bale
weighs
480
pounds.
14
PCNB
Use
on
Cotton
PCNB
is
a
widely
used
fungicide
in
U.
S.
cotton
production
with
the
majority
of
PCNB
use
on
cotton
in
past
years
centered
in
the
southern
and
southeastern
portion
of
the
U.
S.
(
Table
6).
This
is
where
upland
cotton
is
the
dominant
variety.
Areas
where
PCNB
is
used
in
cotton
production
is
in
the
USDA
Farm
Resource
Regions
of
Eastern
Uplands,
Eastern
Seaboard,
and
Mississippi
Portal
(
Farm
Resource
Regions,
2000).

Table
6.
PCNB
use
in
cotton
by
State:
1998,
1999,
2000,
2001,
and
2003
average
State
Total
A.
I.
Percent
Crop
Treated
Number
of
Applications
A.
I.
per
Application
A.
I.
per
Year
Mississippi
87,600
12
1.10
0.51
0.59
Arkansas
68,250
12
1.00
0.58
0.58
Alabama
65,500
17
1.05
0.63
0.67
Tennessee
62,500
17
1.00
0.64
0.65
Louisiana
48,670
11
1.03
0.68
0.73
Georgia
35,000
4
1.50
0.44
0.66
North
Carolina
28,250
6
1.00
0.60
0.61
South
Carolina
4,000
3
1.00
0.60
0.60
All
Program
States
399,800
4
1.02
0.59
0.63
Source:
Agricultural
Chemical
Usage,
Field
Crop
Summary,
1998,
1999,
2000,
2001,
and
2003
(
USDA,
NASS).
Notes:
Sum
of
States
may
not
equal
All
Program
States
due
to
rounding.
All
Program
States
are
those
states
that
USDA
NASS
surveys
for
pesticide
use
on
a
given
crop.
They
survey
states
that
account
for
at
least
80%
of
the
total
production.

Cost
of
PCNB
and
Alternatives
Our
analysis
has
found
that
there
are
two
comparable
alternatives
to
PCNB
in­
furrow
use
in
cotton
that
will
provide,
at
minimum,
equal
control
of
the
pests
targeted
by
PCNB.
These
alternatives
are
azoxystrobin
and
iprodione.
The
per
acre
application
rates
and
costs
of
PCNB
and
these
alternatives
are
given
below.

PCNB
is
typically
applied
in
cotton
at
0.5
to
1.0
Lb
of
a.
i.
per
acre
(
the
label
maximum
application
rate
is
2
lbs
a.
i.
per
acre)
(
USDA,
NASS).
Given
per
acre
application
costs
of
the
product
formulations
under
the
brand
names
Ridomil
and
Terraclor,
and
typical
application
rates
and
use
patterns
in
cotton
production,
the
cost
of
PCNB
is
estimated
to
range
from
$
6.00
to
$
7.50
with
the
typical
per
acre
application
cost
at
$
6.50
per
acre
(
EPA
Proprietary
Data,
and
Mississippi
State
University,
2005).

Azoxystrobin
is
applied
in
cotton
at
0.07
to
0.
Under
the
10
lbs
a.
i.
per
acre
(
U.
S.
EPA
Data).
Given
the
per
acre
application
costs
of
the
product
formulations
under
the
brand
names
Quadris,
and
typical
application
rates
and
use
patterns
in
cotton
production,
the
per
acre
application
cost
of
azoxystrobin
is
estimated
to
range
from
$
9.00
to
$
11.50
with
the
typical
per
acre
application
cost
at
approximately
$
10.00
(
EPA
Proprietary
Data,
and
Mississippi
State
University,
2005).
15
Iprodione
is
applied
in
cotton
at
0.14
to
0.17
lbs
a.
i.
per
acre
(
EPA
Proprietary
Data).
Given
per
acre
application
costs
of
the
product
formulations
under
the
brand
names
Rovral,
and
typical
application
rates
and
use
patterns
in
cotton
production,
the
per
acre
cost
of
iprodione
is
estimated
to
range
from
$
5.50
to
$
7.00
with
the
typical
per
acre
application
cost
at
approximately
$
6.50
(
EPA
Proprietary
Data,
and
Mississippi
State
University,
2005).

Grower
Level
Impacts
This
section
provides
the
impacts
that
cotton
producers
would
be
expected
to
experience
if
PCNB
is
no
longer
available
Information
used
in
this
assessment
is
based
primarily
on
cost
of
production
data
from
the
USDA
Economic
Research
Service,
and
covers
the
USDA
Farm
Resource
Regions
of
Eastern
Uplands,
Eastern
Seaboard,
and
Mississippi
Portal,
which
are
the
areas
where
PCNB
is
most
widely
used
in
U.
S.
cotton
production.

Our
analysis
assumes
that
there
are
equally
effective
alternatives
to
PCNB,
and
that
there
will
be
no
yield
or
quality
losses
to
growers
that
switch
from
PCNB
to
these
alternatives.
It
is
also
assumed
that
there
are
no
additional
application
costs
that
will
arise
from
using
alternatives
instead
of
PCNB.
Given
these
assumptions,
changes
in
operating
costs
associated
with
using
PCNB
alternatives
are
the
sole
source
of
grower
level
impacts
that
could
result
if
cotton
producers
switch
from
using
PCNB
to
the
identified
alternatives.

Cotton
producers
receive
revenue
through
the
sale
of
cotton
and
through
government
support
as
authorized
by
the
Farm
Bill
of
2002.
Table
7
presents
data
describing
the
typical
cost
and
returns
resulting
from
the
sale
of
cotton
for
cotton
producers
in
the
relevant
Farm
Resource
Regions
(
2000).

Table
7.
Cotton
costs
and
returns
per
acre
for
southern
seaboard,
Mississippi
portal,
and
eastern
uplands
production
regions,
2003
and
2004
average
Description
/
Production
Region
Southern
Seaboard
Mississippi
Portal
Eastern
Uplands
Total
operating
costs
324.8
413.09
287.12
Total
costs
509.81
625.10
437.50
Yield,
Cotton:
(
pounds)
793.00
980.50
787.50
Yield,
Cottonseed:
(
pounds)
1283.00
1,587.00
1274.00
Revenue
from
Cotton
428.22
558.89
448.88
Revenue
from
Cottonseed
60.63
77.14
61.38
Total
Revenue
488.85
636.02
510.26
Net
Operating
Revenue
164.05
222.93
223.14
Source:
Cotton
Production
Costs
and
Returns
per
Planted
Acre,
Excluding
Government
payments,
2003­
2004,
USDA,
Economic
Research
Service,
http://
www.
ers.
usda.
gov/
data/
CostsandReturns
The
portion
of
cotton
producers'
revenues
derived
from
government
payments
are
based
on
several
factors.
These
factors
are
described
below
and
are
used
in
combination
with
cotton
production
data
to
estimate
government
payment
by
production
region.
Our
estimates
are
based
16
on
information
from
the
United
States
Department
of
Agriculture,
Economic
Research
Service
(
USDA
ERS).

Eligibility
for
payments
is
based
on
historical
cotton
yield
and
acreage.
The
base
yield
for
the
program
is
93.5
percent
of
the
1998
 
2001
average,
and
base
acreage
is
based
on
85
percent
of
cotton
acreage
for
the
same
time
period.
A
cotton
grower
is
eligible
for
government
payments
on
85%
of
their
base
acreage.
For
government
payments,
the
yield
on
that
base
acreage
is
assumed
to
be
93.5%
of
the
base
yield.
Because
our
estimates
of
the
impacts
are
on
a
per
acre
basis,
we
approximate
base
yield
and
acreage
by
multiplying
the
average
per
acre
yields
(
shown
in
Table
7)
by
0.935
for
base
yield
and
by
multiplying
that
by
0.85
to
approximate
base
yield
on
a
per
acre
basis.
This
calculation
gives
the
per
acre
pounds
of
cotton
eligible
for
government
payments.

We
then
approximate
the
value
of
government
payments
to
cotton
producers
by
subtracting
the
market
price
from
the
target
price
(
the
target
price
equals
$
0.724
per
pound
for
upland
cotton).
This
number
is
then
multiplied
by
the
base
yield
(
on
a
per
acre
basis)
and
is
a
per
acre
approximation
of
government
payments
received
by
cotton
producers.
Cotton
growers
also
receive
direct
and
marketing
loan
program
payments,
but
because
the
marketing
loan
price
is
generally
close
to
the
market
price
and
because
the
market
price
rarely
exceeds
the
target
price,
these
payments
are
captured
in
the
above
calculations.
Table
8
shows
our
estimates
of
government
support
payments
for
the
relevant
Farm
Resource
Regions.

Table
8.
Estimated
per
acre
government
support
payments
to
cotton
producers,
by
farm
resource
region
Description
/
Production
Region
Southern
Seaboard
Mississippi
Portal
Eastern
Uplands
Yield
eligible
for
support
payments
630.24
779.25
625.87
Difference
between
market
price
and
target
price
0.18
0.15
0.15
Per
acre
support
payment
115.96
120.00
96.38
Note:
Calculations
were
made
using
yield
data
shown
in
Table
7.

Grower
level
impacts
of
switching
from
PCNB
to
alternatives
are
measured
on
a
per
acre
basis
and
are
reflected
in
the
change
in
a
typical
producer's
net
operating
revenues
(
net
operating
revenue
is
equal
to
total
revenue
minus
operating
costs).
Changes
in
net
operating
revenues
are
shown
in
the
Table
9.
The
information
shows
the
impact
of
switching
from
PCNB
to
azoxystrobin
because
the
per
acre
costs
for
PCNB
and
iprodione
are
approximately
the
same,
which
means
that
there
are
no
measurable
impacts
of
switching
from
PCNB
to
iprodione
17
Table
9.
Farm
level
per
acre
impacts
of
switching
from
pcnb
to
azoxystrobin,
by
farm
resource
region
Southern
Seaboard
PCNB
Azoxystrobin
Percentage
Change1
Net
Operating
Revenue2
$
164.05
$
161.05
­
2%
Net
Operating
Revenue
(
Including
Support
Payments)
3
$
280.01
$
277.01
­
1%
Mississippi
Portal
PCNB
Azoxystrobin
Percentage
Change1
Net
Operating
Revenue2
$
222.93
$
219.93
­
1%
Net
Operating
Revenue
(
Including
Support
Payments)
3
$
342.93
$
339.93
­
1%
Eastern
Uplands
PCNB
Azoxystrobin
Percentage
Change1
Net
Operating
Revenue2
$
223.14
$
220.14
­
1%
Net
Operating
Revenue
(
Including
Support
Payments)
3
$
319.52
$
316.52
­
1%
Source:
Information
shown
in
the
table
is
based
on
operating
cost
and
revenue
data
from
Tables
7
and
8,
and
pesticide
cost
data
from
above
section,
"
Cost
of
PCNB
and
Alternatives".
Note:
The
per
acre
cost
of
iprodione
is
approximately
the
same
as
PCNB.
For
this
reason,
there
are
no
measurable
impacts
of
switching
from
PCNB
to
iprodione.
1.
Percentage
change
represents
the
change
from
PCNB
to
Azoxystrobin.
2.
"
Net
operating
revenue"
equals
total
revenue
(
excluding
government
payments)
minus
operating
costs.
3.
"
Net
operating
revenue
(
including
support
payments)"
equals
total
revenue
(
including
government
payments)
minus
operating
costs.

Given
that
azoxystrobin
and
iprodione
are
equally
effective
alternatives
to
PCNB,
and
that
they
are
both
similarly
priced
on
a
per
acre
basis
to
PCNB,
we
do
not
anticipate
that
the
impacts
of
switching
from
PCNB
to
either
alternative
would
be
significant.
In
the
case
of
iprodione,
there
are
no
measurable
impacts.
Though
azoxystrobin
is
more
costly
on
a
per
acre
basis,
the
added
costs
would
decrease
net
operating
revenues
by
no
more
than
2%
in
any
of
the
regions
evaluated,
and
would
lead
to
a
reduction
in
net
revenues
(
including
government
support
payments)
by
no
more
than
1%
in
any
of
the
regions.

Conclusion
Azoxystrobin,
iprodione,
and
PCNB
currently
are
the
three
choices
of
fungicides
available
to
farmers
for
in­
furrow
treatment
of
cotton
for
Rhizoctonia
damping­
off.
This
assessment
reviewed
extension
information
and
results
of
26
published
fungicide
trials
that
were
conducted
over
a
four­
year
period.
These
trials
compared
efficacy
of
azoxystrobin,
iprodione,
and
PCNB
and
showed
that,
overall,
azoxystrobin
or
iprodione
were
at
least
as
effective
as
PCNB
for
disease
management.
Resistance
to
these
fungicides
is
not
a
concern
for
managing
Rhizoctonia
damping­
off
disease.
Iprodione
provided
effective
management
of
Rhizoctonia
damping­
off
at
a
cost
similar
to
PCNB.
Azoxystrobin
is
more
expensive
than
PCNB
but,
when
compared
to
18
cotton
producers
overall
economic
situations,
the
anticipated
impact
of
substituting
azoxystrobin
for
PCNB
is
minor.

References
for
Cotton
EPA
Proprietary
Data,
2002,
2003,
and
2004.

Farm
Resource
Regions.
2000.
USDA­
Economic
Research
Service.
http://
www.
ers.
usda.
gov/
publications/
aib760/

FRAC
(
Fungicide
Resistance
Action
Committee).
2005.
Pathogen
risk
list
(
Dec.
2005).
http://
www.
frac.
info/
frac/
index.
htm.

Koenning,
S.
20004.
Cotton
seedling
disease.
North
Carolina
State
University
Plant
Pathology
Department.
Cotton
Disease
Information
Note
No.
1.
http://
www.
ces.
ncsu.
edu/
depts/
pp/
notes/
Cotton/
cdin1/
cdin1.
htm.

Mississippi
State
University,
Department
of
Agricultural
Economics,
Budget
Report
2005­
01,
December
2005,
"
Cotton
2006
Planning
Budgets."

Mueller,
J.
D.
1996.
Cotton
seedling
disease
control.
Clemson
University
Extension,
Edisto
Research
&
Education
Center.
www.
clemson.
edu/
edisto/
cotton/
seedling.
pdf.

TAMU
(
Texas
A&
M
University).
1996.
Plant
pathology
document.
http://
plantpathology.
tamu.
edu/
Texlab/
Fiber/
Cotton/
cotton.
html
TAMU.
2005.
Fungicidee
Seed
Treatments
for
Cotton.
http://
ag­
cares.
tamu.
edu/
pdf/
fungseedtreatcot.
pdf.

UG
(
University
of
Georgia).
2006.
Cotton
disease
and
nematode
management.
2006
Georgia
Cotton
Production
Guide.
Univ.
Georgia
Extension.
http://
www.
griffin.
peachnet.
edu/
caes/
cotton/
2006cottonguide/
cottondiseasemanagement.
pdf
http://
www.
griffin.
peachnet.
edu/
caes/
cotton/

USDA,
ERS.
2002.
Farm
Bill,
Title
I,
Commodity
Programs.
http://
www.
ers.
usda.
gov/
Features/
Farmbill/
titles/
titleIcommodities.
htm.

USDA,
NASS.
1998,
1999,
2000,
2001,
and
2003.
Agricultural
Chemical
Usage,
Field
Crop
Summary.
http://
usda.
mannlib.
cornell.
edu/
reports/
nassr/
other/
pcu­
bb/#
field.

UT
(
University
of
Tennessee).
2005.
http://
www.
utextension.
utk.
edu/
fieldCrops/
cotton/
cotton_
images/
2005­
cotton­
diseasecontrol
pdf
19
Citations
for
in­
furrow
fungicide
trials
published
in
Fungicide
and
Nematicide
(
F&
N)
Tests:

Colyer,
P.
D.
and
Vernon
P.
R.
2003.
Evaluation
of
fungicides
for
seedling
disease
control
in
cotton,
2002.
F&
N
Tests
58:
FC032.

Colyer,
P.
D.
and
Vernon
P.
R.
2004a.
Evaluation
of
fungicides
for
seedling
disease
control
in
cotton
on
clay
soil,
2003.
F&
N
Tests
59:
FC020.

Colyer,
P.
D.
and
Vernon
P.
R.
2004b.
Evaluation
of
fungicides
for
seedling
disease
control
in
cotton,
2003.
F&
N
Tests
59:
FC019.

Lawrence,
K.
S.,
Jones,
J.
R.,
Usery,
S.
R.,
and
Norris,
B.
E.
2004a.
Evaluation
of
selected
infurrow
fungicides
for
management
of
cotton
seedling
disease
in
the
Tennessee
Valley
region
of
Alabama,
2003.
F&
N
Tests
59:
ST024.

Lawrence,
K.
S.,
Jones,
J.
R.,
Usery,
S.
R.,
and
Moore,
D.
2004b.
Evaluation
of
selected
infurrow
fungicides
for
management
of
cotton
seedling
disease
in
central
Alabama,
2003.
F&
N
Tests
59:
ST023.

McLean,
K.
S.,
Campbell,
H.
L.,
Palmateer,
A.
and
Moore,
D.
2001.
Evaluation
of
selected
infurrow
fungicides
for
control
of
Pythium
spp.
and
Rhizoctonia
solani
seedling
disease
in
central
Alabama,
2000.
F&
N
Tests
56:
FC18.

McLean,
K.
S.,
Palmateer,
A.
J.,
Greer,
N.
W.
and
Moore,
D.
2002a.
Evaluation
of
in­
furrow
fungicides
for
control
of
cotton
seedling
disease
in
central
Alabama,
2001.
F&
N
Tests
57:
FC18.

McLean,
K.
S.,
Palmateer,
A.
J.,
Greer,
N.
W.
and
Moore,
D.
2002b.
Evaluation
of
in­
furrow
fungicides
for
control
of
cotton
seedling
disease
in
central
Alabama,
2001.
F&
N
Tests
57:
FC18.

McLean,
K.
S.,
Palmateer,
A.
J.,
Greer,
N.
W.
and
Moore,
D.
2002c.
Evaluation
of
selected
infurrow
fungicides
for
control
of
Rhizoctonia
solani
seedling
disease
of
cotton
in
central
Alabama,
2001.
F&
N
Tests
57:
FC25.

McLean,
K.
S.,
Palmateer,
A.
J.
Greer,
N.
W.
and
Norris,
B.
E.
2002d.
Evaluation
of
in­
furrow
fungicides
for
control
of
seedling
disease
of
cotton
in
north
Alabama,
2001.
F&
N
Tests
57:
FC18.

McLean,
K.
S.,
Palmateer,
A.
J.,
Greer,
N.
W.
and
Moore,
D.
2002e.
Evaluation
of
Terraclor,
Rovral,
and
Quadris
for
control
of
cotton
seedling
disease
of
cotton
in
central
Alabama,
2001.
F&
N
Tests
57:
FC17.
20
McLean,
K.
S.,
Palmateer,
A.
J.,
Greer,
N.
W.
and
Moore,
D.
2002f.
Evaluation
of
in­
furrow
fungicides
for
control
of
Rhizoctonia
solani
seedling
disease
of
cotton
in
central
Alabama,
2001.
F&
N
Tests
57:
FC16.

McLean,
K.
S.,
Palmateer,
A.
J.,
Greer,
N.
W.,
and
Norris,
B.
E.
2002g.
Evaluation
of
in­
furrow
fungicides
for
Rhizoctonia
solani
seedling
disease
of
cotton
in
north
Alabama,
2001.
F&
N
Tests
57:
FC14.

McLean,
K.
S.,
Palmateer,
A.
J.,
Hutchinson,
J.
L.,
and
Norris,
B.
E.
2003a.
Evaluation
of
selected
in­
furrow
fungicides
for
management
of
cotton
seedling
disease
in
the
Tennessee
Valley
region
of
Alabama,
2002.
F&
N
Tests
58:
FC010.

McLean,
K.
S.,
Palmateer,
A.
J.,
Hutchinson,
J.
L.,
and
Moore,
D.
2003b.
Evaluation
of
selected
in­
furrow
fungicides
for
management
of
cotton
seedling
disease
in
central
Alabama,
2002.
F&
N
Tests
58:
FC012.

McLean,
K.
S.,
Palmateer,
A.
J.,
Hutchinson,
J.
L.,
and
Norris,
B.
E.
2003c.
Evaluation
of
infurrow
fungicides
for
management
of
Rhizoctonia
solani
seedling
disease
in
the
Tennessee
Valley
region
of
Alabama,
2002.
F&
N
Tests
58:
FC011.

McLean,
K.
S.,
Palmateer,
A.
J.,
Hutchinson,
J.
L.,
and
Moore,
D.
2003d.
Evaluation
of
selected
in­
furrow
fungicides
for
management
of
Rhizoctonia
solani
seedling
disease
in
the
central
Alabama,
2002.
F&
N
Tests
58:
FC013.

Padgett,
G.
B.
and
Price,
J.
L.
2001.
In­
furrow
and
foliar
fungicides
for
seedling
disease
management,
2000.
F&
N
Tests
56:
FC27.

Padgett,
G.
B.
and
Rea,
W.
2002.
In­
furrow
or
hopper­
box
applications
of
fungicides
for
the
management
of
seedling
diseases,
2001.
F&
N
Tests
57:
FC30.

Padgett,
G.
B.
and
Rea,
W.
2003.
In­
furrow
or
hopper­
box
applications
of
fungicide
for
the
management
of
seedling
diseases,
2002.
F&
N
Tests
58:
FC015.

Padgett,
G.
B.
and
Garber,
B.
C.
W.
2004.
Selected
in­
furrow
applied
fungicides
for
seedling
disease
management
in
cotton,
2003.
F&
N
Tests
59:
FC005.

Phipps,
P.
M.
and
Maitland,
J.
C.
2002.
Response
of
cotton
to
in­
furrow
fungicide
treatments
at
planting
for
seedling
disease
control,
2001.
F&
N
Tests
57:
FC28.

Phipps,
P.
M.
2004.
Effect
of
seed
treatments
and
in­
furrow
fungicides
on
emergence,
growth
and
yield
of
cotton,
2003.
F&
N
Tests
59:
FC070.

Phipps,
P.
M.
and
Rideout,
S.
L.
2005a.
Effect
of
seed
treatment
and
in­
furrow
fungicide
on
emergence,
growth
and
yield
of
cotton,
2004.
F&
N
Tests
60:
ST025.
21
Phipps,
P.
M.
and
Rideout,
S.
L.
2005b.
Effect
of
in­
furrow
fungicide
treatments
on
seedling
emergence,
growth
and
yield
of
cotton,
2004.
F&
N
Tests
60:
ST081.

Seebold,
K.
W.
and
Horton,
T.
B.
2003.
Evaluation
of
in­
furrow
fungicides
for
the
control
of
seedling
diseases
of
cotton,
2002.
F&
N
Tests
58:
FC024.

POTATOES
According
to
the
U.
S.
Department
of
Agriculture,
there
were
200,000
pounds
of
PCNB
applied
to
potatoes
in
2003,
and
85,000
were
applied
in
2001
(
USDA,
NASS).
Washington
was
the
only
major
production
state
that
used
PCNB.
PCNB
use
appears
to
be
regional,
with
the
most
use
in
the
northwestern
U.
S.
PCNB
was
used
on
38%
of
Washington
potatoes
and
3%
of
Idaho
potatoes.

Two
of
the
most
important
cultural
means
of
managing
potato
diseases
are
crop
rotation
and
use
of
clean
potato
seed­
pieces
(
WPC,
2006).
In
Washington,
typically
crops
are
grown
for
one
year
and
rotated
out
of
potatoes
for
three
years
(
WPC,
2006).
In
addition,
fungicide
treatment
of
seed
pieces
helps
create
a
healthy
crop
(
WPC,
2006).
Treating
seed
pieces
is
essential
to
achieving
healthy
plants
at
emergence.
Effective
seed
piece
treatments
include
flutolanil
+
mancozeb
(
Moncoat
MZ),
fludioxonil
(
Maxim),
fludioxonil
+
mancozeb
(
Maxim
MZ),
thiophanate­
methyl
+
mancozeb
(
Tops
MZ)
(
Zitter
and
Halseth,
2004).
PCNB
is
not
used
for
this
purpose.

Diseases
Managed
with
PCNB
Stem
canker
and
black
scurf.
PCNB
is
primarily
used
in­
furrow
when
planting
potato
seedpieces
to
manage
the
soil­
borne
pathogen
Rhizoctonia
solani,
cause
of
stem
canker
and
black
scurf.
R.
solani
attacks
tubers,
underground
stems,
and
stolons
of
potato
plants
(
Crop
Profiles
North
Dakota,
2000).
It
is
generally
only
a
problem
when
seed
potatoes
are
planted
in
cool,
wet
soils.

White
mold.
PCNB
is
used
in
some
areas
as
a
foliar
application
for
suppression
of
white
mold
caused
by
Sclerotinia
sclerotiorum,
a
pathogen
with
a
wide
host
range.
While
this
disease
is
not
listed
on
standard
PCNB
labels
as
a
target
pest,
there
are
Special
Local
Needs
(
SLN)
labels
in
effect
for
use
of
PCNB
through
chemigation
in
Washington,
Nevada
and
Idaho.

The
white
mold
pathogen
overwinters
in
the
soil
as
sclerotia.
In
spring
the
sclerotia
germinate
and
produce
spore­
forming
structures
(
apothecia),
which
infect
potato
leaves
and
stem
(
OSU,
2005).
Because
of
long­
term
viability
of
the
pathogen
in
the
soil
and
its
wide
host
range,
crop
rotations
of
four
or
more
years
with
non­
host
rotation
crops
(
e.
g.,
corn)
may
be
required
to
reduce
inoculum
where
disease
pressure
has
been
high
(
Maine,
1991;
Olsen
et
al.,
2003).
Weed
management
to
control
weeds
that
are
susceptible
to
the
pathogen
is
also
an
important
management
strategy
(
Olsen
et
al.,
2003).
The
severity
of
the
disease
can
be
localized
depending
on
conducive
conditions
(
primarily
in
moist
conditions,
including
frequent
irrigation
(
WSU,
1994).
According
to
Oregon
State
University
(
OSU)
extension,
"
Though
widespread,
and
at
times
appearing
to
be
quite
damaging,
the
effect
of
yield
is
likely
marginal
in
most
fields,
22
particularly
in
the
Columbia
Basin"
(
OSU,
2005).
In
addition,
OSU
extension
states
that
"
the
disease
must
be
severe
for
fungicide
application
to
be
economically
effective"
(
OSU,
2005).
In
cooler
climates,
white
mold
can
be
a
significant
problem
if
not
properly
managed
(
Maine,
1991).
Reducing
humidity
among
plants
by
increasing
spacing,
decreasing
vine
growth,
and
irrigating
less
frequently
can
help
reduce
disease
(
OSU,
2005;
WSU,
1994).

Fungicide
Alternatives
to
PCNB
Seed­
piece
fungicide
treatment.
PCNB
is
not
used
for
seed­
piece
treatment
of
potatoes,
but
treating
seed
pieces
with
labeled
fungicides
before
planting
is
a
common
approach
to
preventing
soil
diseases
of
young
potato
plants.
There
are
several
fungicides
that
are
effective
in
controlling
Rhizoctonia,
as
well
as
other
soil­
borne
pathogens.
According
to
Zitter
and
Halseth
(
2004),
"
with
Rhizoctonia
being
a
major
concern,
growers
now
have
the
option
to
select
between
several
seed
piece
products.
Moncoat
MZ
with
the
active
ingredient
flutolanil
is
very
active
for
Rhizoctonia
and
provides
safe
control
of
Fusarium.
The
biological
agent
T­
22
Planter
Box
(
Trichoderma
harzianum)
has
good
activity
against
Rhizoctonia,
and
may
also
suppress
Pythium
and
Fusarium.
Two
additional
products
that
extend
the
range
of
pathogens
controlled
are
Tops
MZ
and
Maxim
MZ.
Tops
MZ
relies
upon
the
activity
of
thiophanate
methyl
plus
mancozeb
to
provide
activity
against
Rhizoctonia,
Fusarium,
and
silver
scurf
(
Helminthosporium
solani).
This
product
has
not
performed
as
well
as
others
for
daughter
tuber
protection
against
silver
scurf
in
tests
conducted
at
Freeville.
On
the
other
hand,
Maxim
MZ
(
active
ingredient
fludioxonil
with
mancozeb)
has
provided
consistent
control
of
Rhizoctonia,
Fusarium,
and
silver
scurf".

In­
furrow
fungicide
treatment
for
managing
Rhizoctonia
diseases.
In­
furrow
applications
of
fungicides
are
the
major
chemical
means
to
manage
black
scurf
and
stem
canker
caused
by
R.
solani.
Azoxystrobin
(
Amistar
®
80%,
Quadris
®
)
,
flutolanil
(
Moncut
®
70%),
and
PCNB
were
all
rated
"
best"
in
an
evaluation
in
New
York
(
Zitter
and
Halseth,
2004).
No
significant
difference
in
yield
was
found
between
in­
furrow
applications
of
azoxystrobin,
flutolanil,
and
PCNB
in
a
trial
in
Wisconsin
(
Stevenson
et
al.,
2004).
According
to
Zitter
and
Halseth
(
2004),
azoxystrobin,
flutolanil,
as
well
as
PCNB
have
shown
"
excellent
Rhizoctonia
control".
Zitter
and
Halseth
(
2004)
have
observed
that
some
potato
cultivars
have
delayed
emergence
with
the
highest
rates
of
azoxystrobin.

Typical
use
rates
(
Zitter,
2006)
for
in­
furrow
application
for
azoxystrobin
(
for
a
36"
row)
range
from
0.1
to
0.14
lb
a.
i.
per
acre.
Flutolanil
typically
is
used
in­
furrow
at
rates
ranging
from
0.5
to
0.75
lb
a.
i.
per
acre.
PCNB
typically
is
used
at
rates
ranging
from
5
to
10
lb
a.
i.
per
acre.

Fungicide
treatment
applied
to
potato
plants
for
managing
white
mold.
Fungicide
applications
for
white
mold
control
generally
are
applied
to
base
of
plants
or
through
chemigation,
where
allowed.
If
disease
pressure
is
high,
fungicides
are
usually
recommended.
For
example,
in
Oregon
(
OSU,
2005)
(
Table
10)
recommendations
for
fungicides
when
disease
is
likely
include
boscalid,
fluazinam,
iprodione,
thiophanate­
methyl,
and
PCNB.
DCNA
is
among
recommended
treatments
and
is
currently
undergoing
reregistration.
23
Fluazinam
has
a
multi­
site
mode
of
action
making
it
an
excellent
partner
for
alternating
or
tankmixing
with
site­
specific
fungicides
(
such
as
thiophanate­
methyl
and
iprodione),
which
may
have
higher
rates
of
resistance
to
the
white
mold
pathogen.
PCNB
has
been
used
for
this
purpose,
but
fluazinam
is
an
effective
alternative
with
a
lower
risk
of
resistance
development
(.
Michigan
specialists
(
Wharton
and
Kirk,
2005)
recommend
iprodione,
fluazinam,
azoxystrobin,
thiophanate­
methyl,
DCNA,
and
boscalid
for
managing
white
mold.
A
consortium
of
growers
from
Colorado,
Nebraska,
Wyoming,
and
Montana
recommend
boscalid,
fluazinam,
iprodione,
and
DCNA
(
Schwartz
and
Gent,
2005).

Table
10.
Recommended
fungicides
for
management
of
white
mold
of
potato
in
Oregon
(
OSU,
2005).
Fungicide
A.
I.
(
Product)
Rate
(
lb
a.
i./
A)
Maximum
amount
or
applications
per
season
REI
(
hours)
PHI
(
days)
Risk
of
Resistanceb
Boscalid
(
Endura
®
)
0.2­
0.4
2
appl/
season
12
30
Medium
Fluazinam
(
Omega
®
)
0.18­
0.26
1.8
lb
a.
i./
A/
season
48
14
Low
Thiophanate­
methyl
(
Topsin
®
)
0.7­
1
2.8
lb/
A/
season
12
21
High
Iprodione
(
Rovral
®
)
1
4
appl/
season
24
14
Medium­
High
PCNB
(
Blocker
®
)
1.5­
5
20
lb
a.
i./
A/
season
12
45
Low­
Medium
a
Oregon
State
University
Extension
(
OSU,
2005).
b
According
to
the
National
Potato
Council,
based
on
information
from
the
Fungicide
Resistance
Action
Committee,
http://
www.
nationalpotatocouncil.
org/
NPC/
p_
documents/
document_
210506110218.
pdf.

Risk
of
Resistance
to
Fungicides
The
risk
of
Rhizoctonia
developing
resistance
to
fungicides
is
considered
"
low"
(
FRAC,
2005)
and
the
one­
time
application
at
planting
reduces
pathogen
exposure
in
the
soil.
The
risk
of
Sclerotinia
sclerotiorum
developing
resistance
to
fungicides
is
considered
"
medium"
(
FRAC,
2005).
Because
there
are
several
fungicides
available
for
rotation
throughout
the
season
for
white
mold
management,
and
because
these
alternative
fungicides
have
different
chemistries
and
modes
of
action
(
including
fluazinam
with
multi­
site
activity),
effective
alternatives
to
PCNB
can
acceptably
manage
this
disease
without
concern
for
development
of
pathogen
resistance.

U.
S.
Potato
Production
and
PCNB
Use
on
Potatoes
According
to
pesticide
use
data
available
from
the
USDA
(
USDA,
NASS),
PCNB
is
used
primarily
in
Washington
Potato
Production
with
minor
use
also
occurring
in
Idaho.
Surveys
of
pesticide
use
patterns
further
indicate
that
the
primary
use
of
PCNB
is
for
control
of
black
scurf/
stem
canker.
White
mold
suppression,
though
a
secondary
benefit
of
PCNB,
is
not
the
primary
target
pest
(
EPA
Proprietary
Data).
Table
11
provides
potato
production
and
PCNB
use
data
for
Idaho
and
Washington,
the
states
where
PCNB
is
predominantly
used
in
potato
production.
24
Table
11.
Fall
potato
production
and
PCNB
use
in
Idaho
and
Washington
Data
Idaho
Washington
Potato
Production
Harvested
Acres
345,000
158,000
Yield
(
CWT)
360
595
Production
(
1,000
CWT)
124,200
94,010
Price
(
CWT)
$
4.65
$
5.25
Value
of
production
(
1,000)
$
577,530
$
493,552
PCNB
Use
Percent
crop
treated
3
38
Total
a.
i.
Applied
10,000
184,000
A.
i.
per
Application
1
1.77
Number
of
Applications
1
1.7
A.
i.
per
Year
1.07
3
Source:
Source:
United
States
Department
of
Agriculture,
National
Agricultural
Statistics
Service:
Crop
Production
2003
Summary,
Crop
Production
2005
Summary,
Crop
Values
2003
Summary,
Crop
Values
2005
Summary,
Agricultural
Chemical
Usage,
Field
Crop
Summary,
2003,
USDA,
NASS.

Cost
of
PCNB
and
Alternatives
Data
for
the
average
application
rate
and
per
acre
cost
of
PCNB
and
its
identified
alternatives
were
taken
from
EPA
data
sources
(
EPA
Proprietary
Data).
PCNB
is
applied
in
potato
production
at
an
average
rate
of
1.80
lbs
of
a.
i.
per
acre
at
an
average
cost
of
$
16.30.
Azoxystrobin
is
applied
in
potato
production
at
an
average
rate
of
0.11
lbs
of
a.
i.
per
acre
at
an
average
cost
of
$
15.05.
Flutolanil
is
applied
in
potato
production
at
an
average
rate
of
0.54
lbs
of
a.
i.
per
acre
at
an
average
cost
of
$
23.00.

Grower
Level
Impacts
This
section
provides
the
impacts
that
potato
producers
would
be
expected
to
experience
if
PCNB
is
no
longer
available.

This
assessment
focuses
on
Washington
State
because
only
3
percent
of
Idaho
potato
acreage
is
treated
with
PCNB,
and
because
the
vast
majority
of
PCNB
use
on
potato
(
approximately
95%)
is
in
Washington.
Information
used
in
this
assessment
is
based
primarily
on
cost
of
production
data
from
the
State
of
Washington
(
Hinman,
H.,
G.
Pelter,
and
E.
Sorensen,
2001),
production
data
from
USDA
(
USDA,
NASS),
and
pesticide
cost
data
from
above.

Our
analysis
assumes
that
there
are
equally
effective
alternatives
to
PCNB,
and
that
there
will
be
no
yield
or
quality
losses
to
growers
that
switch
from
PCNB
to
these
alternatives.
It
is
also
assumed
that
there
are
no
additional
application
costs
that
will
arise
from
using
alternatives
instead
of
PCNB.
Given
these
assumptions,
changes
in
operating
costs
associated
with
using
PCNB
alternatives
are
the
sole
source
of
grower
level
impacts
that
could
result
if
potato
producers
switch
from
using
PCNB
to
the
identified
alternatives.
Grower
level
impacts
of
switching
from
PCNB
to
alternatives
are
measured
on
a
per
acre
basis
and
are
reflected
in
the
change
in
a
typical
producer's
net
operating
revenues
(
net
operating
revenue
is
equal
to
total
revenue
minus
operating
costs).
Table
12
provides
a
summary
of
the
impact
of
switching
from
25
PCNB
to
flutolanil.
Note
that
low
and
high
production
cost
scenarios
represent
the
variation
in
production
practices
and
costs
associated
with
potatoes
destined
for
the
fresh
and
processed
markets.

Table
12.
Grower
and
state
level
impacts
of
switching
from
PCNB
to
flutolanil
for
control
of
black
scurf/
stem
canker
Data
Description
PCNB
Flutolanil
Low
Cost
Production
Scenario
High
Cost
Production
Scenario
Low
Cost
Production
Scenario
High
Cost
Production
Scenario
Change
In
Pesticide
Costs
$
0
$
0
$
7
$
7
Total
Operating
Cost
$
1,644
$
1,931
$
1,651
$
1,937
Initial
Total
Cost
$
2,374
$
2,660
$
2,380
$
2,666
Yield
(
CWT)
595
595
595
595
Total
Revenue
$
3,124
$
3,124
$
3,124
$
3,124
Net
Operating
Revenue
$
1,479
$
1,193
$
1,473
$
1,186
%
Change
In
Net
Operating
Revenue
0%
0%
0%
1%
Source:
Hinman,
H.,
G.
Pelter,
and
E.
Sorensen,
2001,
"
Cost
Of
Producing
Processing
And
Fresh
Potatoes
Under
Center
Pivot
Irrigation
Columbia
Basin,
Washington
(
EB
1906)",
Washington
State
University
Cooperative
Extension.
United
States
Department
of
Agriculture,
National
Agricultural
Statistics
Service:
Crop
Production
2003
Summary
and
U.
S.
EPA
Data
Note:
Low
and
high
Production
cost
scenarios
represent
the
variation
in
production
practices
and
costs
associated
with
potatoes
destined
for
the
fresh
and
processed
markets.

Per
acre
application
costs
of
flutolanil
are
higher
than
PCNB
($
6.67
per
acre).
This
added
production
cost
reduces
net
operating
revenues
by
1%
in
the
high­
cost
scenario.
This
reduction
is
well
outside
the
range
of
impacts
that
would
typically
reduce
the
economic
viability
of
potato
production.

Given
that
PCNB
and
azoxystrobin
are
similarly
priced,
with
azoxystrobin
being
approximately
$
1
cheaper,
the
impact
of
switching
from
PCNB
to
azoxystrobin
is
minimal.
The
secondary
benefit
of
mold
suppression
is,
however,
not
included
in
this
analysis
and
might
explain
why
growers
use
PCNB
instead
of
azoxystrobin
at
the
present
time.

Conclusion
Azoxystrobin
and
flutolanil
are
fungicides
that
are
effective
for
in­
furrow
application
to
manage
Rhizoctonia
solani.
These
fungicides
provide
at
least
equal
efficacy
to
in­
furrow
applications
of
PCNB
for
managing
R.
solani
in
potato.
For
control
of
white
mold
of
potato,
several
fungicides
are
available
that
are
applied
throughout
the
season
to
manage
this
disease.
PCNB
is
considered
suppressive
of
the
pathogen
Sclerotinia
sclerotiorum
and
has
not
been
the
primary
fungicide
used
for
management
of
white
mold.
Changes
in
cost
of
potato
production
and
its
impact
on
net
revenues
are
expected
to
be
minimal
with
use
of
azoxystrobin
or
flutolanil,
instead
of
PCNB.
Based
on
our
finding
that
effective
alternatives
are
available
for
white
mold
control,
we
did
not
evaluate
the
benefit
of
white
mold
suppression
capacity
provided
by
PCNB.
26
References
for
Potatoes
Crop
Profiles
Potatoes
in
Michigan.
2000.
http://
www.
ipmcenters.
org/
cropprofiles/
docs/
MIPotato.
html
Crop
Profiles
Potatoes
in
North
Dakota.
2000.
http://
www.
ipmcenters.
org/
cropprofiles/
docs/
Ndpotatoes.
html
EPA
Proprietary
Data,
2002,
2003,
and
2004.

FRAC
(
Fungicide
Resistance
Action
Committee).
2005.
Pathogen
risk
list
(
Dec.
2005).
http://
www.
frac.
info/
frac/
index.
htm.

Maine
(
University
of
Maine).
1991.
Potato
Facts:
White
Mold.
Extension
Publication
2248.
http://
www.
umext.
maine.
edu/
onlinepubs/
htmpubs/
2248.
htm.

Olsen,
N.,
Miller,
J.,
Nolte,
P.,
and
Miller,
T.
2003.
White
mold
and
potatoes.
University
of
Idaho
Extension
Bulletin
CIS
1105.
http://
www.
kimberly.
uidaho.
edu/
potatoes/
CIS1105.
pdf.

OSU
(
Oregon
State
University),
2005.
Potato
(
Solanum
turberosum) 
White
mold
(
Sclerotinia
stem
rot).
Oregon
State
University
Extension.
http://
plantdisease
ippc.
orst.
edu/
disease.
cfm?
recordID=
911.

Schwartz,
H.
F.
and
Gent,
D.
H.
2005.
White
mold.
www.
highplainsipm.
org/
HpIPMSearch/
docs/
whitemold­
potato.
htm.

Stevenson,
W.
R.,
James,
R.
V.,
Rand,
R.
E.
2004.
Evaluation
of
the
efficacy
of
seedpiece
or
infurrow
fungicide
treatment
for
potato
disease
control 
Montello,
WI,
2003.
Fungicide
and
Nematicide
(
F&
N)
Tests
59:
V042.

Thomas,
J.
2005.
Response
to
inquiry
from
Western
Integrated
Pest
Management
Center.
http://
www.
wrpmc.
ucdavis.
edu/
NewsAlerts/
pcnbresponsepnw.
pdf.

USDA,
NASS.
2001
and
2003.
Agricultural
Chemical
Usage,
Field
Crop
Summary.
http://
usda.
mannlib.
cornell.
edu/
reports/
nassr/
other/
pcu­
bb/#
field
Wharton,
P.
and
Kirk,
W.
2005.
White
mold.
Michigan
State
University
Department
of
Plant
Pathology.
http://
www.
potatodiseases.
org/
whitemold.
html.

WSU
(
Washington
State
University).
1994.
Sclerotinia
stem
rot
on
potato.
Washington
State
University
Extension
Bulletin
1790.
http://
cru.
cahe.
wsu.
edu/
CEPublications/
eb1790/
eb1790.
html
Zitter,
T.
A.
and
Halseth,
D.
E.
2004.
Potato
seed
piece
and
in­
furrow
treatments
for
2004.
Cornell
University
Department
of
Plant
Pathology.
http://
vegetablemdonline.
ppath.
cornell.
edu/
NewsArticles/
Pot_
Treat2004.
html
27
Zitter,
T.
A.
2006.
Potato
fungicides
(
labeled
and
rates/
A)
as
of
March
23,
2006.
Cornell
University,
Department
of
Plant
Pathology.
http://
vegetablemdonline.
ppath.
cornell.
edu/
NewsArticles/
Pot_
LabeledRts.
html
COLE
CROPS
(
Cabbage,
Brussels
Sprouts
and
Cauliflower)

The
term
"
cole"
crops
refers
to
plants
in
the
crucifer
family
within
the
genus
Brassica
(
more
specifically,
varieties
of
the
species
Brassica
oleracea)
that
have
similar
pest
complexes.
These
crops
include
cabbage,
collards,
mustard
greens,
turnip
greens,
radish,
broccoli,
Brussels
sprouts,
cauliflower,
Chinese
cabbage,
and
kale.
For
this
assessment,
we
have
reviewed
the
management
of
two
fungal
diseases
(
clubroot
and
wirestem)
affecting
cabbage,
cauliflower
and
Brussels
sprouts
that
are
controlled
by
PCNB.

PCNB
is
labeled
(
Table
13)
for
the
control
of
clubroot
(
caused
by
Plasmodiophora
brassicae)
disease
and
wirestem
(
caused
by
Rhizoctonia
solani).
A
one
time
per
season
application
of
PCNB
is
made
at
planting
in­
furrow,
as
a
transplant
dip,
or
broadcast
(
NY,
1999).
Approximately
23,000
lbs
of
PCNB
is
used
per
on
cabbage,
Brussels
sprouts
and
cauliflower.

Clubroot
Disease.
The
infected
roots
enlarge,
become
distorted,
and
resemble
clubs.
The
disease
development
on
the
roots
of
affected
plants
can
be
extensive
before
above­
ground
portions
show
any
symptoms.
Leaves
on
infected
plants
turn
yellow,
wilt,
and
die.
Clubroot
can
be
a
problem
in
cole
crop
production.
Commonly
less
than
1%
of
the
broccoli
acreage
in
Michigan
is
affected
with
clubroot,
but
100%
yield
losses
can
occur
in
infected
acreage
(
MI
Crop
Profile
Broccoli,
1999).
In
New
York,
the
largest
cabbage
producer,
typical
yield
losses
range
from
1­
15%,
but
can
be
as
high
as
50%
in
severely
infested
fields
(
NY
Crop
Profiles,
1999).
In
California,
approximately
1180
acres
(
approximately
3
percent
of
total
acreage
of
cauliflower)
were
treated
with
PCNB
for
the
control
of
this
pest
during
1997
(
CA
Crop
Profile
Cauliflower,
2000).
The
disease
incidence
and
affected
acreage
varies
from
state
to
state.

Pathogen.
This
disease
is
caused
by
the
fungus
Plasmodiophora
brassicae.
The
fungus
gains
entrance
into
the
plant
by
attaching
to
the
root
hairs.
As
the
fungus
begins
to
develop
in
the
roots,
it
produces
spores.
These
spores
are
released
and
can
be
disseminated
by
water
and
infested
soil.
Acid
soils
and
cool
wet
weather
favor
pathogen
development.
The
disease
is
not
seed­
borne.

Control.
Location
of
the
seedbed
is
important
in
clubroot
management.
To
avoid
local
and
wide­
spread
distribution
of
the
pathogen,
the
seed
and
transplant
should
be
planted
in
diseasefree
soil.
Hydrated
lime
incorporated
into
the
soil
to
raise
the
pH
to
7.2
reduces
clubroot;
however,
on
muck
soils
the
application
of
lime
is
of
little
value
because
of
the
high
soil
buffering
capacity.
Clubroot
can
be
reduced
by
using
PCNB
fungicides
as
per
label
recommendations.
These
control
programs
should
be
coupled
with
crop
rotation
(
MN,
1999;
WI,
2004).
28
PCNB
is
usually
applied
once
at
planting
time.
The
recommended
method
of
application
for
the
control
of
clubroot
is
transplant
solution
[
6
lbs/
A
in
100
gallon
water
(
equal
to
4.5
lbs
ai)],
band
or
broadcast
application
[
15­
40
lbs/
A
in
25
to
50
gallon
of
water
(
equal
to
11­
30
lbs
ai/
A)].

Alternatives
to
PCNB
for
club
root
control.
Clubroot
disease
incidence
and
severity
can
be
reduced
by
PCNB.
There
is
no
other
registered
fungicide
(
Table
13)
that
may
reduce
the
disease
(
Louws,
2005;
NY
Crop
Profile
Cabbage,
1999;
MI
Crop
Profiles
Cauliflower,
1999;
HI,
unknown
date;
MN,
1999;
IL,
1989;
Good,
2005;
Lewis
Ivey
et
al.,
2004a,
2004b,
2004c).
However,
raising
pH
of
the
soil
to
7.2­
7.5
can
prevent
serious
losses
to
the
disease.
The
soil
fumigants
(
such
as
metam
sodium
and
methyl
bromide)
control
the
disease
(
Louws,
2005;
NY
Crop
Profile
Cabbage,
1999;
MI
Crop
Profiles
Cauliflower,
1999;
HI,
unknown
date;
MN,
1999;
IL,
1989;
Good,
2005;
Lewis
Ivey
et
al.,
2004a,
2004b,
2004c;
UW,
2004),
but
this
may
not
be
a
feasible
solution
for
small
growers.
Long
crop
rotation
with
non
cruciferous
crops
(
6­
7
years)
and
raising
soil
pH
to
7­
2­
7.5
have
been
recommended
to
reduce
disease
pressure
and
incidence,
but
these
practices
may
not
be
commercially
feasible
options
(
e.
g.,
NY,
1999;
IL,
1989).

Wirestem
Disease:
Wirestem
gets
its
name
from
symptoms
that
occur
on
the
stem
at
the
soil
level.
A
dark,
water
soaked
lesion
initially
appears
on
the
stem.
Later
stems
become
wiry
and
slender
at
the
point
of
the
lesion.
This
disease
usually
affects
seedlings
and
newly
transplanted
plants,
when
disease
pressure
is
high
and
plants
are
stressed
due
to
inadequate
soil
moisture.
The
affected
crucifer
plants
may
grow
poorly,
are
stunted
and
may
eventually
die.
If
infected
plants
remain
alive,
the
stem
becomes
tough
and
woody.
Plants
that
survive
usually
mature
late
and
fail
to
produce
a
marketable
head
(
VA,
2000).

Pathogen:
The
pathogen
(
Rhizoctonia
solani)
is
present
in
the
field
soils
and
transplant
seedlings
may
be
infested
without
symptoms.

Control.
Planting
disease
free
transplants
in
well­
drained
soils
can
reduce
disease
severity
and
incidence.
If
seed
is
planted
rather
than
transplants,
seed
planted
as
shallow
as
possible,
when
soil
temperature
reaches
69
°
F
(
21
°
C)
or
higher,
encourages
rapid
germination
and
emergence
for
plants
to
escape
R.
solani
infections.
PCNB
can
be
used
in
the
transplant
dip
water.
However,
according
to
NY
Crop
Profile
for
Cabbage
(
1999),
yield
losses
are
usually
from
damping­
off
diseases
early
in
plant
development,
rather
than
from
the
later
development
of
wirestem.
Soil
fumigation
of
plant
beds
will
eradicate
Rhizoctonia
solani;
however,
fumigated
soil
can
become
reinfested
if
pathogen­
infested
field
soil
is
moved
to
fumigated
areas.
For
R.
solani,
PCNB
is
applied
once
as
row
or
broadcast
or
drench
at
the
time
of
or
immediately
after
seeding
(
15­
40
lbs/
A
in
25
to
50
gallon
of
water,
equal
to
11­
30
lbs
ai/
A).

Alternatives
to
PCNB
for
wirestem
control.
Azoxystrobin
is
registered
for
use
on
cole
crops
in
broadcast
or
band
applications,
or
transplant
drench
for
managing
wirestem
(
Table
13).
Fludioxonil
(
Maxim
4FS)
is
an
effective
seed
treatment
that
protects
seedlings
against
Rhizoctonia
diseases.
Azoxystrobin
has
been
reported
to
reduce
wirestem
disease
incidence
on
heading
Brassica
vegetables
from
44%
(
in
infested
control)
to
0.05%
(
Keinath
et
al.,
2003).
In
another
trial
azoxystrobin
reduced
disease
incidence
from
19.5%
(
in
infested
control)
to
2.6%
29
(
Keinath
et
al.,
2002).
Shallow
planting
has
been
reported
to
reduce
disease
incidence
by
50­
90%
(
Keinath
et
al.,
2003;
Keinath
et
al.,
2004).

Table
13.
PCNB
and
alternatives
used
on
cole
crops
(
cabbage,
califlower
and
Brussels
sprouts).

Disease/
Pest
Application
method
(
PCNB)
Fungicide
Alternatives
(
Trade
Name)*
Application
method
(
Alternative
s)
Efficacy
of
Alternatives
Clubroot
(
Plasmodiophora
brassicae)
Transplant
solution,
Band
and
broadcast
application,
Row
drench
treatment
No
fungicide
is
registered
as
an
alternative
to
PCNB.
Metam
sodium
and
methyl
bromide
(
soil
fumigants)
kill
the
pathogen,
but
may
not
be
feasible
due
to
cost
or
regulatory
issues.
NA
Clubroot
disease
pathogen
can
only
be
controlled
or
suppressed
using
soil
fumigants
(
metam
sodium
and
methyl
bromide).
Raising
soil
pH
to
6.8­
7.2
prevent
serious
losses
to
this
disease
(
Louws,
2005;
NY
Crop
Profile
Cabbage,
1999;
MI
Crop
Profiles
Cauliflower,
1999;
HI,
unknown
date;
MN,
1999;
IL,
1989;
Good,
2005).
Transplant
seedling
must
be
disease
free.

Azoxystrobin
(
Amistar)
Labeled
for
aerial
&
ground
application
and
chemigation
Wirestem
(
Rhizoctoni
solani)
Band
and
Broadcast
application,
drench
application
Fludioxonil
(
Maxim
4FS)
Seed
treatment
Fludioxonil
seed
treatment
and
azoxystrobin
ground
application
is
reported
to
control
this
disease
(
NY
Crop
Profile
Cabbage,
1999;
MI
Crop
Profiles
Cauliflower,
1999;
Keinath
et
al.,
2002,
2003,
2004).
Azoxystrobin
alone
has
been
found
to
control
this
disease
very
effectively
(
Keinath
et
al.,
2002,
2003,
2004).

Risk
of
Resistance
to
Fungicides
The
risk
of
Rhizoctonia
developing
resistance
to
fungicides
is
considered
"
low"
(
FRAC,
2005).
Presently,
azoxystrobin
is
an
effective
alternative
to
PCNB
for
field
application
for
the
control
of
the
wirestem
pathogen
with
no
reports
of
Rhizoctonia
resistance
in
cole
crops.
There
appear
to
be
no
reports
of
resistance
to
the
seed
treatment
fludioxonil
by
Rhizoctonia.
30
U.
S.
Cole
Crop
Production
Brussels
sprouts
and
cauliflower
are
grown
predominantly
in
California
(
Table
14).
Cabbage
is
grown
throughout
the
U.
S.
with
major
production
states
including
California,
Florida,
Georgia,
New
York,
North
Carolina,
and
Texas.

Table
14.
Brussels
sprouts,
cabbage,
and
cauliflower
area
harvested,
production,
and
value
for
2005.1
Commodity
State
Acres
Harvested
Production
1,000
CWT
Value
of
production
1,000
Dollars
Brussels
sprouts1
California
2,200
396
$
14,471
Cabbage
Arizona
3,100
1,395
$
22,739
California
13,300
4,655
$
70,291
Colorado
3,400
1,632
$
15,504
Florida
7,800
2,652
$
31,294
Georgia
10,000
2,800
$
30,800
Illinois
750
236
$
2,053
Michigan
1,400
630
$
3,969
New
Jersey
1,500
390
$
6,942
New
York
9,700
4,559
$
67,289
North
Carolina
6,500
1,430
$
15,730
Ohio
1,400
252
$
4,360
Pennsylvania
1,300
221
$
4,022
Texas
8,700
2,610
$
41,499
Virginia
750
169
$
2,451
Wisconsin
4,100
615
$
6,519
United
States
73,700
24,246
$
325,462
Cauliflower
Arizona
4,700
1,010
$
39,693
California
31,900
5,396
$
154,377
New
York
900
104
$
3,349
United
States
37,500
6,510
$
197,419
Source:
USDA
National
Agricultural
Statistics
Service
­
Quick
Stats,
U.
S.
&
All
States
Data
­
Vegetables,
2001
and
2005.
http://
www.
nass.
usda.
gov:
8080/
QuickStats/
Create_
Federal_
All.
jsp.
1.
California
is
the
major
U.
S.
producer
of
Brussels
sprouts.
Production
data
collection
for
California
Brussels
sprouts
was
discontinued
after
2001.
Note:
Data
for
Brussels
Sprouts
is
for
2001.
All
other
data
is
from
2005.

PCNB
Use
on
Cole
Crops
We
reviewed
pesticide
use
data
from
the
U.
S.
Department
of
Agriculture
(
USDA
NASS),
California
Pesticide
Use
Reports
(
CA­
DPR,
2001­
2004),
and
EPA
pesticide
use
data
(
EPA
proprietary
data)
to
identify
PCNB
use
patterns
in
the
cole
crops.
According
to
these
sources,
cabbage
and
Brussels
sprouts
are
the
only
crops
where
PCNB
has
been
used
in
recent
years.
Fewer
than
5,000
lb
of
PCNB
are
applied
annually
in
cabbage
production,
with
the
majority
of
the
application
occurring
in
New
York
(
EPA
proprietary
data).
Approximately
5,000
lbs
of
PCNB
are
applied
annually
in
California
on
Brussels
sprouts
(
CA­
DPR,
2001­
2004).
Use
of
PCNB
in
cabbage
production
has
been
predominantly
for
the
control
of
clubroot
(
EPA
31
Proprietary
Data).
The
Agency
does
not,
however,
have
pesticide
use
data
that
describes
PCNB
target
pests
in
Brussels
sprout
production.

Cost
of
PCNB
and
Alternatives
When
used
in­
furrow,
PCNB
is
applied
once
per
growing
season
and
at
a
typical
rate
range
of
6­
15
lb
per
acre
(
EPA
Proprietary
Data;
NY,
1999)
and
can
be
applied
in­
furrow
at
the
same
rate
for
both
wirestem
and
clubroot.
PCNB
costs
are
approximately
$
60­
150
per
acre
at
$
10
per
pound
(
EPA
Proprietary
Data).

Azoxystrobin
has
been
identified
as
a
PCNB
alternative
for
the
control
of
wirestem
in
cole
crop
production.
For
wirestem
control,
azoxystrobin
would
typically
be
applied
once
per
year
at
a
rate
of
0.25
pounds
per
acre,
and
a
cost
of
approximately
$
33
per
acre,
which
is
less
than
the
$
10
per
pound
required
for
PCNB.

Seed
treatments
using
fludioxonil
are
also
effective
against
wirestem
in
cole
crops.
However,
at
present,
the
Agency
does
not
have
adequate
information
to
gauge
the
per
acre
cost
of
this
control
method.

Grower
Level
Impacts
Based
on
our
above
review
that
there
are
no
comparable
alternatives
to
PCNB
for
the
control
of
clubroot
in
cole
crops.
If
PCNB
is
no
longer
available,
we
expect
the
impact
on
affected
producers
could
be
significant
for
fields
with
a
history
of
clubroot
disease.
At
present,
cole
crop
production
where
PCNB
is
applied
to
treat
clubroot
can
experience
yield
losses
of
up
to
15%
(
NY,
1999).
As
stated
above,
yield
losses
could
approach
100%
without
PCNB
in
heavily
infested
fields.
Losses
of
these
magnitudes
would
be
expected
to
lead
to
significant
impacts
to
affected
cole
crop
producers.

For
managing
wirestem
disease,
azoxystrobin
provides
as
good,
or
better,
control
compared
to
PCNB,
and
at
a
lower
cost.
Seed
treatment
using
fludioxonil
also
provide
excellent
control
of
wirestem.
Given
that
there
are
effective
treatments
for
this
disease,
and
the
finding
of
low
reported
use
of
PCNB
(
EPA
Proprietary
Data),
we
do
not
anticipate
that
cole
crop
producers
would
experience
significant
adverse
economic
impacts
as
a
result
of
using
alternative
wirestem
disease
management
treatments
instead
of
PCNB.

Conclusion
PCNB
may
be
important
for
the
management
of
clubroot
disease
of
cole
crops
where
disease
pressure
is
high
and
the
growers
can
not
fumigate
their
fields
with
metam
sodium.
Other
fungicides
do
not
appear
to
be
effective
in
managing
this
disease.
Cultural
control
methods,
such
as
a
long
rotation
(
6­
7
years)
with
non­
cruciferous
crops,
and
changing
soils
to
pH
7.2­
7.5,
may
not
be
practical
options
for
managing
this
disease
under
field
conditions.

PCNB
is
not
essential
for
the
control
of
wirestem
disease
of
cole
crops
since
registered
alternatives
are
at
least
equally
effective
in
managing
the
disease.
In
addition,
shallow
planting
32
will
further
reduce
R.
solani
disease
incidence
by
50­
90
percent.
Fludioxonil
seed
treatment
provides
additional
protection
to
cole
crops
against
this
pest.
Switching
from
PCNB
to
azoxystrobin
and
using
fludioxonil­
treated
seed
will
result
in
minor
impacts,
especially
since
PCNB
appears
to
have
limited
use
on
these
crops.

References
for
Cole
Crops
CA
Crop
Profile
for
Cauliflower.
2000.
http://
cipm.
ncsu.
edu/
cropprofiles/
docs/
cacauliflower.
html
CA­
DPR
(
California
Department
of
Pesticide
Regulation),
California
Pesticide
Information
Portal,
2001­
2004,
http://
calpip.
cdpr.
ca.
gov/
cfdocs/
calpip/
prod/
main.
cfm.

EPA
Proprietary
Data,
2002,
2003,
and
2004.

FRAC
(
Fungicide
Resistance
Action
Committee).
2005.
Pathogen
risk
list
(
Dec.
2005).
http://
www.
frac.
info/
frac/
index.
htm.

Good,
G.
2005.
Cornell
University
comment
through
USDA.
Seed
and
in
furrow
treatment
is
important
against
clubroot
disease.

HI
(
University
of
Hawaii)
(
unknown
date).
Clubroot:
Use
clean
and/
or
treated
seed.
University
of
Hawaii
Extension.
http://
www.
extento.
hawaii.
edu/
kbase/
reports/
recommendations/
colecrops.
asp
IL
(
University
of
Illinois).
1989.
Clubroot
of
cabbage
and
other
crucifers.
University
of
Illinois
Extension
Bulletin
No.
923.
http://
web.
aces.
uiuc.
edu/
vista/
pdf_
pubs/
923.
PDF;
http://
www.
aces.
uiuc.
edu/
ipm/
fruits/
cole/
cole_
mgtrec.
html#
Club%
20Root
Keinath,
A.
P.,
Dubose,
V.
B.
May
III.
2003.
Evaluating
soil­
applied
fungicides
to
control
wirestem
on
heading
Brassica
vegetables.
F
&
N
Tests
Vol.
60:
V003.

Keinath,
A.
P.,
Dubose,
V.
B.
May
III,
W.
H.
and
Cantrell,
J.
P.
2004.
Evaluating
new
soilapplied
fungicides
to
control
wirestem
on
heading
Brassica
vegetables.
F
&
N
Tests
Vol.
60:
V038.

Keinath,
A.
P.,
Dubose,
V.
B.,
Cantrell
and
May
III,
W.
H.
2002.
Evaluating
foliar­
applied
fungicides
to
control
wirestem
on
heading
Brassica
vegetables.
F
&
N
Tests
Vol.
58:
V010.

Lewis
Ivey,
M.
L.,
Mera,
J.
R.
and
Miller
S.
A.
2004a.
Evaluation
of
fungicides
for
the
management
of
clubroot
in
mustard
greens.
F
&
N
Tests
Vol.
60:
V100.

Lewis
Ivey,
M.
L.,
Mera,
J.
R.
and
Miller
S.
A.
2004b.
Evaluation
of
fungicides
for
the
management
of
Rhizoctonia
hypocotyls
rot,
clubroot
and
downy
mildew
in
radishes.
F
&
N
Tests
Vol.
60:
V097.
33
Lewis
Ivey,
M.
L.,
Mera,
J.
R.
and
Miller
S.
A.
2004c.
Evaluation
of
fungicides
for
the
management
clubroot
on
radishes.
F
&
N
Tests
Vol.
60:
V098.

Louws,
F.
2005.
NC
through
USDA.
PCNB
is
no.
1
choice
for
controlling
clubroot
and
wire
stem
diseases
and
does
not
have
any
alternative.

MI
Crop
Profile
for
Broccoli.
1999.
http://
www.
cips.
msu.
edu/
cropprofiles/
Broccoli/
BroccoliInMichigan.
html
MI
Crop
Profile
for
Cauliflower.
1999.
Http://
pestdata.
ncsu.
edu/
cropprofiles/
docs/
micauliflower.
html
MN
(
University
of
Minnesota).
1999.
Clubroot.
University
of
Minnesota
Extension.
http://
www.
extension.
umn.
edu/
distribution/
horticulture/
dg1169.
html
NY.
1999.
Crop
Profile
Cabbage
for
New
York.
http://
www.
ipmcenters.
org/
cropprofiles/
docs/
nycabbage.
html
USDA­
NASS,
2005,
Agricultural
Chemical
Usage,
Vegetable
Summary,
http://
usda.
mannlib.
cornell.
edu/
reports/
nassr/
other/
pcu­
bb/#
vegetables.

VA
(
Virginia
Tech
University).
2000.
Wire
Stem
and
Bottom
Rot
of
Cabbage.
Virginia
Tech
Cooperative
Extension
Publication
Number:
450­
713..
http://
www.
ext.
vt.
edu/
pubs/
plantdiseasefs/
450­
713/
450­
713.
html
WI
(
University
of
Wisconsin).
2004.
Cole
crops
disorder:
Clubroot.
University
of
Wisconsin
Extension
Bulletin
No.
A1128.
http://
cecommerce.
uwex.
edu/
pdfs/
A1128.
pdf#
search='
cole%
20crops%
20and%
20club%
20ro
ot
GREEN
(
SNAP)
BEANS
Green
bean,
Phaseolus
vulgaris,
belongs
to
the
Leguminosae,
or
pea,
family.
The
seeds
are
planted
when
the
soil
temperature
is
above
62
degrees
F
in
spring
and
summer.
Spring
crop
snap
beans
are
planted
1
to
1
1/
2
inches
deep
after
the
beginning
of
the
frost­
free
period.
Fall
crop
snap
beans
are
planted
early
enough
in
the
summer
for
harvest
to
be
completed
before
the
first
killing
frost.
Row
spacing
for
bush
beans
is
2­
3
inches
in
the
row
and
18
to
36
inches
between
rows.
The
optimum
temperature
for
plant
growth
is
60
to
70
degrees
F.
Snap
beans
require
moist
soil
for
germination.
Water
availability
at
pod
fill
is
also
critical
to
ensure
high
yields.
Because
of
the
relatively
shallow
root
system
of
the
snap
bean
the
water
requirement
is
high
(
Mossler
and
Nesheim,
2000).

Approximately
30,000
lb
PCNB
are
used
per
year
to
treat
green
beans
(
EPA
Proprietary
Data).
PCNB
is
labeled
for
the
control
of
root/
stem
rot
(
caused
by
Rhizoctonia
solani)
and
white
mold
34
(
Sclerotinia
sclerotiorum)
diseases.
The
recommended
PCNB
application
method
for
the
control
of
R.
solani
is
band
row
treatment
directed
spray
in
the
seed
furrow
and
to
the
covering
soil
at
planting
and
in­
furrow
application.
For
S.
sclerotiorum,
PCNB
is
applied
once
as
a
spray
on
bands
centered
on
a
row
immediately
after
or
at
the
time
of
planting.
Later,
sprays
are
directed
to
the
soil
at
the
base
of
plants.
PCNB
application
rates
are
2.75
lbs/
A
(
equal
to
2
lbs
ai/
A)
in
8­
10
gallons
of
water.

White
Mold
Disease.
White
mold
is
caused
by
Sclerotinia
sclerotiorum,
it
is
also
called
sclerotinose,
watery
soft
rot,
and
Sclerotinia
rot
of
beans.
It
is
one
of
the
key
diseases
of
snap
beans
during
the
cool
season.
The
disease
also
affects
vegetable
crops,
including
potato,
tomato,
cabbage,
celery,
and
lettuce,
as
well
as
wild
hosts,
particularly
ragweed.
Approximately
15
percent
of
snap
bean
acreage
is
affected
with
white
mold
in
Florida
(
Mossler
and
Nesheim,
2000).

The
presence
of
small,
black
resting
structures
(
sclerotia)
and
a
cottony,
white
mass
(
mycelium)
are
characteristic
of
the
pathogen.
Sclerotia,
which
are
able
to
survive
between
crop
cycles,
are
the
source
of
inoculum
infesting
individual
fields
from
year
to
year.
Usually,
white
mold
in
snap
beans
appears
after
the
start
of
blossoming.
The
fungus
enters
senescent
petals
and
from
there
moves
into
the
plant,
killing
the
stem
above
the
infection
point.
The
pathogen
can
also
enter
the
plant
through
leaves
or
pods
on
the
soil
surface
(
Mossler
and
Nesheim,
2000;
Pernezny
and
Purdy,
1994).

Pathogen.
This
pathogen
prefers
cool
and
moist
weather.
The
resulting
disease
is
most
severe
at
temperatures
in
the
range
of
60
to
70
°
F
(
15
to
21
°
C).
The
disease
is
spread
most
readily
under
conditions
of
high
humidity
with
dew
formation.
Reduced
air
circulation
due
to
close
plant
spacing
or
weed
growth
increases
severity
of
the
disease.
Under
sufficiently
moist
conditions,
sclerotia
in
the
soil
produce
infectious
spores,
which
are
carried
in
the
air
and
splashing
rain
to
host
plants,
initiating
disease
development
upon
germination.
Sprinkler
irrigation
may
favor
disease
development,
and
poor
drainage
can
also
increase
white
mold
problems.
Timing
of
fungicidal
applications
is
critical.
Essential
time
for
treatment
is
during
the
blooming
period,
when
the
fungus
attacks
senescing
flower
petals
(
Mossler
and
Nesheim,
2000;
Pernezny
and
Purdy,
1994;
Simone,
1998;
Pernezny,
1997).

Control.
PCNB
is
a
protectant
fungicide
that
snap
bean
growers
apply
at
planting
for
the
management
of
white
mold
disease.

Alternatives
to
PCNB.
The
other
fungicides
registered
(
Table
15)
for
use
on
beans,
for
the
control
of
white
mold,
are:
dicloran
(
Botran
®
75­
W),
pyraclostrobin
(
Cabrio
®
EG,
Headline),
boscalid
(
Endure
®
)
,
iprodione
(
Iprodione
4L
AG,
Rovral
®
75WG),
azoxystrobin
(
Quadris
®
)
,
thiophanate­
methyl
(
Thiophante
Methyl
85WDG).
Under
field
conditions,
boscalid,
azoxystrobin
and
thiophanate
methyl
have
been
reported
to
reduce
disease
incidence
and
severity
that
equals
or
better
than
PCNB
(
Strausbaugh
and
Koehn,
2003a;
Strausbaugh
and
Koehn,
2003b;
Strausbaugh
et
al.,
2002;
CA,
1999).
35
Rhizoctonia
Root/
Stem
Rot
Disease.
The
disease
causes
postemergence
damping­
off
of
the
seedlings
that
is
characterized
by
sharp­
edged
oval
to
elliptical
reddish
brown
lesions
on
the
hypocotyl.
Heavy
infection
may
girdle
the
stem
and
the
seedlings
may
die.
Often
the
lesions
heal
over
as
the
plant
ages.
Rhizoctonia
root
canker
also
occasionally
occurs
on
the
upper
taproots
of
older
plants
as
discrete,
reddish
brown
lesions.
The
disease
is
most
severe
at
15­
18
degrees
C
(
60­
65
F).
Soil
moisture
has
little
effect
on
disease
severity.
Seedlings
and
young
plants
are
susceptible
to
disease
whereas
the
disease
is
rarely
a
problem
on
older
plants.
However,
the
pathogen
can
affect
aerial
parts
of
plants
under
high
disease
pressure.

Pathogen.
The
pathogen
survives
between
crop
seasons
as
sclerotia
or
mycelium
in
soil
in
or
on
infested
plant
debris
or
on
perennial
plants.
It
may
be
borne
on
or
in
bean
seed.
It
is
generally
disseminated
in
infested
soil
or
plant
debris
by
wind,
rain,
irrigation
water
and
farm
equipment.
When
soils
become
infested,
they
remain
so
for
many
years.

Control.
Cultural
practices
such
as
shallow
seeding,
rotation
of
beans
with
non­
host
crops,
and
planting
in
warm
soil
may
significantly
reduce
Rhizoctonia
root
rot.
PCNB
spray
is
applied
once
in
the
seed
furrow
and
to
the
covering
soil
at
planting
time
to
control
this
disease.
Metam
sodium
fumigation
has
also
been
recommended
for
heavily
infested
soils
(
http://
cipm.
ncsu.
edu/
cropprofiles/
docs/
Cabeans­
green.
html).

Alternatives
to
PCNB.
Azoxystrobin,
chlorothalonil,
iprodione
,
pyraclostrobin
and
fludioxonil+
mefenoxam
are
registered
for
use
on
beans
to
control
R.
solani
(
Table
15).
Azoxystrobin,
chlorothalonil
and
iprodione
have
been
reported
to
be
highly
effective
in
controlling
R.
solani
on
beans
when
applied
as
foliar
treatment
to
control
root
rot
and
aerial
infections
(
Kirk
et
al.,
2000;
Cody
and
Cubeta,
2001;
Waldenmaier,
2004).
Iprodione
has
been
reported
to
be
highly
effective
against
this
pathogen
(
Spotts
and
Cervantes,
1996).
Azoxystrobin
+
chlorothalonil
treated
plots
had
the
least
amount
of
root
rot
(
77%
disease)
in
comparison
to
the
untreated
control
(
100%
disease)
and
other
fungicide
treatments
(
Kirk
et
al.,
2000).
Azoxystrobin
treatments
also
reduced
R.
solani
infections
on
pea
pod
(
71­
92
percent).
36
Table
15.
PCNB
use
on
beans
(
green)
and
alternative
fungicides.

Disease/
Pest
Application
method
(
PCNB)
Fungicide
Alternatives
(
Trade
Name)*
Application
method
(
Alternatives)
Efficacy
Dicloran
(
Botran
75­
W)
Chemigation
Pyraclostrobin
(
Cabrio
EG,
Headline)
Ground
and
Air
Boscalid
(
Endure)
Ground,
air
or
sprinkler
Irrigation
Iprodione
(
Iprodione
4L
AG,
Rovral
75WG)
Ground,
Air,
spray
to
seed
furrow
and
Chemigation
Azoxystrobin
(
Quadris)
Ground
Spray
and
drip
chemigation
White
mold
(
Sclerotinia
sclerotiorum):
Band,
row
and
in
seedfurrows
Thiophanatemethyl
(
Thiophante
Methyl
85WDG
Ground
Spray
Azoxystrobin,
boscalid,
iprodione,
thiophanate
methyl
are
effective
against
soil
level
and
aerial
infections
of
this
pest
(
Kucharek
2005;
Gibbs,
2005;
Mulrooney,
2005;
Eaten,
2005;
Louws,
2005;
Toth,
2005;
Mossler
and
Nesheim,
2000;
simone,
1998;
Pernezny
and
Purdy,
1994).
The
efficacy
of
these
fungicides
has
been
reported
to
be
as
good
or
sometimes
better
than
PCNB
in
controlling
the
disease
(
Kucharek
2005;,
Strausbaugh
and
Koehn,
2003a;
Strausbaugh
and
Koehn,
2003b;
Strausbaugh
et
al.,
2002).
Iprodione
has
been
reported
to
be
highly
effective
against
this
pest
(
Spotts
and
Cervantes,
1996).

Azoxystrobin
(
Amister)
In
furrow
and
band
application,
Chemigation
Chlorothalonil
(
Equus
500ZN)
Air,
ground
and
chemigation
Iprodione
(
Iprodione
4L
AG,
Rovral
75WG)
Ground,
Air,
spray
to
seed
in
furrow
and
Chemigation
Pyraclostrobin
(
Headline)
In
furrow,
ground,
air
and
chemigation
Root/
Stem
rot
(
Rhizoctonia
solani)
Band,
Row
and
infurrows
Fludioxonil+
mefenoxam
(
Apron
Maxx
RTA),
Seed
treatment,
effective
against
R.
solani,
Pythium
and
Phytpphthora
PCNB
use
is
not
critical
to
growers.
A
combination
of
alternative
registered
fungicides
are
likely
to
provide
commercially
acceptable
disease
control.
In
addition,
cultural
practices
will
further
reduce
disease
incidence
*
Listed
are
US­
EPA
registered
fungicide
alternatives
on
given
crops.
The
registration
was
confirmed
using
http://
premier.
cdms.
net/
WebApls/
FormsLogin.
asp?/
WebApls
37
Risk
of
Resistance
to
Fungicides
The
risk
of
Rhizoctonia
developing
resistance
to
fungicides
is
considered
"
low"
(
FRAC,
2005).
The
risk
of
Sclerotinia
sclerotiorum
developing
resistance
to
fungicides
is
considered
"
medium"
(
FRAC,
2005).
Because
there
are
several
fungicides
available
with
different
chemistries
and
modes
of
action
(
Table
15)
effective
alternatives
to
PCNB
appear
to
be
available
to
acceptably
manage
both
pathogens
without
pathogen
resistance.

U.
S.
Snap
Bean
Production
Snap
beans
are
an
important
vegetable
crop
grown
throughout
the
United
States,
with
an
average
total
value
of
production
from
2003
to
2005
of
approximately
$
400
million
(
Table
16).
Snap
beans
are
grown
for
both
the
fresh
and
processing
market
in
the
U.
S.
Table
16
shows
the
area
harvested,
production,
and
the
value
of
production
for
snap
beans
grown
for
both
fresh
consumption
and
processing
by
state
for
2003
to
2005.

Table
16.
U.
S.
snap
bean
(
fresh
and
processed)
area
harvested,
production,
and
value:
2003
 
2005
average.
Produced
for
the
Fresh
Market
Produced
for
the
Processing
Market
State
Area
Harvested
(
Acres)
Production
(
Thousand
CWT*)
Value
of
Production
(
Thousand
Dollars)
Area
Harvested
(
Acres)
Production
(
Thousand
CWT*)
Value
of
Production
(
Thousands
Dollars)
California
6,367
637
$
39,690
Delaware
2,900
9,250
$
1,775
Florida
33,000
2,557
$
142,158
2,100
9,300
$
2,274
Georgia
16,833
800
$
27,289
Illinois
14,833
58,847
$
8,491
Indiana
5,800
17,390
$
3,093
Maryland
1,667
48
$
1,848
2,700
6,350
$
1,288
Michigan
4,100
185
$
5,858
17,933
56,250
$
9,352
New
Jersey
2,767
107
$
4,858
New
York
8,500
294
$
21,233
21,167
70,887
$
13,177
North
Carolina
5,733
277
$
8,997
Oregon
17,433
110,683
$
20,120
Other
States
38,470
137,760
$
25,425
Pennsylvania
10,267
32,443
$
6,938
South
Carolina
1,100
47
$
2,149
Tennessee
9,200
479
$
15,913
Virginia
4,833
209
$
6,166
1,000
2,850
$
690
Wisconsin
71,600
301,587
$
32,038
United
States
94,100
5,640
$
276,159
200,403
795,097
$
120,643
Source:
United
States
Department
of
Agriculture,
National
Agricultural
Statistics
Service:,
Crop
Production
2003­
2005
Summaries
and
Crop
Values
2003­
2005.

*
CWT
indicates
that
the
value
is
in
100
pound
units.
38
PCNB
Use
on
Snap
Beans
According
to
EPA
Proprietary
Data
and
USDA
NASS,
an
annual
average
of
30,000
pounds
of
PCNB
are
used
in
snap
bean
production
in
the
U.
S.
The
majority
of
PCNB
use
in
snap
beans
(
approximately
90%)
is
in
Florida
and
Georgia.
These
are
states
that
grow
predominantly
for
the
fresh
market
with
Florida
accounting
for
approximately
10%
of
total
U.
S.
snap
bean
acreage
and
35%
of
fresh
market
snap
bean
acreage,
and
Georgia
accounting
for
approximately
5%
of
total
U.
S.
snap
bean
acreage
and
20%
of
fresh
market
snap
bean
acreage.
PCNB
is
applied
in
these
states
at
about
1
pound
per
acre
and
typically
once
per
growing
year
(
USDA
NASS).

Costs
of
PCNB
and
Alternatives
Table
17
shows
typical
application
rates
and
prices
for
PCNB
and
those
active
ingredients
identified
as
alternatives
for
PCNB
in
snap
bean
production.

Table
17.
Typical
application
rates
and
per
acre
costs
for
use
of
PCNB
and
alternatives
in
snap
bean
production.
Active
Ingredient
Average
Application
Rate
per
Acre
(
Lbs)
Average
Cost
per
Acre
PCNB
0.90
$
10
Azoxystrobin
0.15
$
19
Boscalid
0.45
$
83
Chlorothalonil
1.45
$
11
Iprodione
0.80
$
30
Thiophanate­
Methyl
1.05
$
25
Source:
EPA
Proprietary
Data,
and
USDA
NASS.

Grower
Level
Impacts
This
section
provides
the
impacts
that
snap
bean
producers
would
be
expected
to
experience
if
PCNB
is
no
longer
available.
Information
used
in
our
assessment
is
based
primarily
on
cost
of
production
data
from
Florida
snap
bean
production
for
the
fresh
market
(
Table
18).
This
is
because
budgets
describing
typical
cost
and
returns
to
snap
bean
producers
and
other
cost
information
covering
Georgia
snap
bean
production
are
not
readily
available.
Total
costs
and
operating
costs
will
likely
vary
between
Georgia
and
Florida,
but
because
several
of
the
available
alternatives
are
similarly
priced
to
PCNB,
we
do
not
anticipate
significantly
different
impacts
would
be
experienced
in
Georgia
as
in
Florida,
should
PCNB
no
longer
be
available.
Data
sources
covering
fresh
market
snap
bean
production
are
used
because
fresh
snap
beans
are
the
variety
predominantly
grown
in
both
Georgia
and
Florida.

Our
analysis
assumes
that
there
are
equally
effective
alternatives
to
PCNB,
and
that
there
will
be
no
yield
or
quality
losses
to
growers
that
switch
from
PCNB
to
these
alternatives.
It
is
also
assumed
that
there
are
no
additional
application
costs
that
will
arise
from
using
alternatives
instead
of
PCNB.
Given
these
assumptions,
changes
in
operating
costs
associated
with
using
PCNB
alternatives
are
the
sole
source
of
grower
level
impacts
that
could
result
if
snap
bean
producers
switch
from
using
PCNB
to
the
identified
alternatives.
39
Grower
level
impacts
of
switching
from
PCNB
to
alternatives
are
measured
on
a
per
acre
basis
and
are
reflected
in
the
change
in
a
typical
producer's
net
operating
revenues
(
net
operating
revenue
is
equal
to
total
revenue
minus
operating
costs)
when
using
PCNB
and
alternatives.
Changes
in
net
operating
revenues
are
shown
in
the
table
rows
below
entitled
"
Net
Operating
Revenue"
and
"%
Change
In
Net
Operating
Revenue"
for
PCNB
and
each
alternative.
Other
rows
in
the
table
show
source
information
used
in
the
calculation
of
net
operating
revenue.

Table
18.
Florida
farm
level
per
acre
impacts
of
switching
from
PCNB
to
alternatives
in
fresh
snap
bean
production
Category
PCNB
Azoxystrobin
Boscalid
Chlorothalonil
Iprodione
Thiophanate­
Methyl
Change
in
fungicide
costs
$
0
$
9
$
73
$
1
$
20
$
15
Total
Fungicide
costs
$
161
$
170
$
234
$
162
$
181
$
176
Total
Operating
Cost
$
1,553
$
1,562
$
1,626
$
1,554
$
1,573
$
1,568
Total
Costs
$
4,082
$
4,091
$
4,155
$
4,083
$
4,102
$
4,098
Yield
per
Acre
(
CWT)
78
78
78
78
78
78
Total
Revenue
$
4,308
$
4,308
$
4,308
$
4,308
$
4,308
$
4,308
Net
Operating
Revenue
$
2,755
$
2,746
$
2,682
$
2,754
$
2,735
$
2,739
%
Change
in
Net
Operating
Revenue
0%
0%
3%
0%
1%
1%
Source:
"
Snap
Beans:
Estimated
production
costs
in
the
Dade
County
area,
2004­
2005,"
Cost
of
Production
for
Florida
Vegetables
2004­
05,
University
of
Florida,
http://
www.
agbuscenter.
ifas.
ufl.
edu/
cost/
and
Yield
and
revenue
data
are
2003­
2005
average
taken
from
USDA­
NASS,
Quick
Stats
Agricultural
Statistics
Database,
U.
S.
and
State
Data,
Vegetables,
2003­
2005.
http://
www.
nass.
usda.
gov/
Data_
and_
Statistics/
Quick_
Stats/
index.
asp.
Note:
Price
of
fresh
snap
per
CWT
is
$
55.60
and
is
a
2003
 
2005
average.

As
reflected
in
Table
18,
snap
bean
producers
under
typical
Florida
production
systems,
have
very
thin
operating
margins.
However,
because
the
cost
of
PCNB
and
its
alternatives
are
similar
in
cost,
using
PCNB
alternatives
would
be
anticipated
to
have
a
minimal
economic
impact
on
snap
bean
producers.
Of
the
five
identified
PCNB
alternatives,
the
greatest
impact
would
come
from
switching
to
boscalid
from
PCNB,
and
would
result
in
a
3%
reduction
in
net
operating
revenues.
Use
of
other
alternatives
would
result
in
a
zero
to
1%
reduction
in
net
operating
revenues.

Conclusion
For
management
of
white
mold
on
green
beans
there
are
several
alternatives
to
PCNB
available
to
farmers.
Under
field
conditions,
boscalid,
azoxystrobin
and
thiophanate
methyl
have
been
reported
to
reduce
white
mold
disease
incidence
and
severity
with
equal,
or
greater,
efficacy
to
PCNB.

For
the
management
of
Rhizoctonia
root
and
stem
rots
on
green
beans,
there
are
effective
alternatives
to
PCNB.
Azoxystrobin
or
pyraclostrobin,
and
iprodione
are
among
the
registered
alternatives
that
are
as
effective
as
PCNB
in
managing
the
disease.
40
Green
bean
growers,
under
typical
production
systems,
have
thin
operating
margins.
However,
because
the
cost
of
PCNB
and
alternative
fungicides
are
similar,
there
are
likely
to
be
minimal
impacts
on
net
revenues
to
these
growers
if
alternatives
are
used
instead
of
PCNB.

References
for
Beans:

CA.
1999.
Crop
Profile
for
Green
Beans
in
California.
http://
cipm.
ncsu.
edu/
cropprofiles/
docs/
Cabeans­
green.
html
Cody,
B.
R
and
Cubeta,
M.
A.
2001.
Fungicide
evaluation
for
snap
bean
pod
rot.
F
&
N
Tests
Vol.
57:
V004.

Eaten,
Alan.
2005.
NH
through
USDA.
Rotation
or
delayed
planting
will
handle
the
problem.
Approximately
5
acres
are
treated
with
PCNB
in
NH.

EPA
Proprietary
Data,
2002,
2003,
and
2004.

FRAC
(
Fungicide
Resistance
Action
Committee).
2005.
Pathogen
risk
list
(
Dec.
2005).
http://
www.
frac.
info/
frac/
index.
htm.

Gibbs,
Mac.
2005.
NC
through
USDA.
Some
growers
use
PCNB+
mefenoxam
for
damping­
off.
Some
growers
use
azoxystrobin
for
damping­
off.

Kirk,
W.
W.
Shaw,
R.
S
and
Schafer,
R.
L.
2000.
Evaluation
of
foliar
treatment
for
snap
bean
root
rot.
F
&
N
Tests
Vol.
56:
V71.

Kucharek,
Thomas.
2005.
FL
through
USDA.
PCNB
used
by
some
growers.
It
is
not
a
dependable
fungicide
for
the
suppression
of
Rhizoctonia
spp.

Louws,
Frank.
2005.
NC
through
USDA.
Used
occasionally
on
snap
beans
as
a
rescue
treatment
if
high
disease
incidence.

Mossler,
M.
A.
and
Nesheim,
O.
N.
2000.
Florida
Crop/
Pest
Management:
Snap
Beans.
Florida
Cooperative
Extension
Service
Bulletin
CR1231.
http://
edis.
ifas.
ufl.
edu/
PI032
Mulrooney,
Bob.
2005.
DE
through
USDA.
Used
against
Rhizoctonia
and
Sclerotinia
although
there
are
alternatives
such
as
azoxystrobin.
PCNB
is
less
prone
to
resistance.

Pernezny,
K.
and
Purdy,
L.
H.
(
1994).
Sclerotinia
Diseases
of
Vegetable
and
Field
Crops
in
Florida.
Plant
Pathology
Fact
Sheet
PP­
22.
Florida
Cooperative
Extension
Service,
Institute
of
Food
and
Agricultural
Sciences,
University
of
Florida.
http://
edis.
ifas.
ufl.
edu/
scripts/
VH015
Pernezny,
K.
(
1997).
Controlling
white
mold
and
common
bacterial
blight.
Citrus
&
Vegetable
Magazine
62(
4):
26­
27.
41
Simone,
G.
W.
(
1998).
Disease
Control
in
Beans:
Bush,
Lima,
Pole,
Wax
(
Phaseolus
spp.)
and
Southern
Peas
(
Vigna
spp.).
Plant
Pathology
PDMG­
V3­
33.
Florida
Cooperative
Extension
Service,
Institute
of
Food
and
Agricultural
Sciences,
University
of
Florida.

Spotts,
R.
A
and
Cervantes,
L.
A.
1996.
Sclerotinia
rot
of
pears
in
Oregon.
Plant
Disease
80:
1262­
1264.

Strausbaugh,
C.
A
and
Koehn,
A.
C.
2003a.
Control
of
white
mold
of
dry
beans
with
foliar
sprays
in
Jerome
County,
ID.
F
&
N
Tests
Vol.
59:
FC001.

Strausbaugh,
C.
A
and
Koehn,
A.
C.
2003b.
Control
of
white
mold
of
dry
beans
with
foliar
sprays
in
Minidoka
County,
ID.
F
&
N
Tests
Vol.
59:
FC002.

Strausbaugh,
C.
A,
Forster,
R.
L
and
Koehn,
A.
C.
2002.
Control
of
white
mold
of
dry
beans
with
foliar
sprays
in
Jerome
County,
ID.
F
&
N
Tests
Vol.
58:
FC52.

Toth,
S.
2005.
TN
through
USDA.
Its
in­
furrow
use
is
important
for
protection
against
R.
solani.
No
mention
of
alternatives.

USDA,
NASS.
2000,
2002,
and
2004.
Agricultural
Chemical
Usage,
Vegetable
Summary.
http://
usda.
mannlib.
cornell.
edu/
reports/
nassr/
other/
pcu­
bb/.

Waldenmaier,
C.
M.
2004.
Evaluation
of
fungicides
for
control
of
web
blight
in
snap
beans.
F
&
N
Tests
Vol.
60
F
&
N
Tests
Vol.
087.
