UNITED
STATES
ENVIRONMENTAL
PROTECTION
AGENCY
WASHINGTON,
D.
C.
20460
April
13,
2006
OFFICE
OF
PREVENTION
PESTICIDES
AND
TOXIC
SUBSTANCES
Memorandum
SUBJECT:
Biological
and
Economic
Analysis
of
Dichlorvos
in
Mushroom
Houses
FROM:
Don
Atwood,
Entomologist
Biological
Analysis
Branch
TJ
Wyatt,
Economist
Economic
Analysis
Branch
Biological
and
Economic
Analysis
Division
(
7503C)

THRU:
Arnet
Jones,
Chief
Biological
Analysis
Branch
Tim
Kiely,
Acting
Chief
Economic
Analysis
Branch
Biological
and
Economic
Analysis
Division
(
7503C)

TO:
Dayton
Eckerson/
Eric
Olson,
Chemical
Review
Manager
Reregistration
Branch
1
Special
Review
and
Reregistration
Division
(
7508C)

PRP
REVIEW
DATE:
March
31,
2006
SUMMARY
The
amount
of
dichlorvos
used
in
mushroom
houses
is
relatively
low.
While
Sciarid
flies
are
now
generally
controlled
through
exclusion,
sanitation,
and
the
use
of
IGR
=

s
to
control
the
larval
stage,
Phorid
fly
control
still
depends
on
adulticides.
There
are
few
aduticides
registered
for
use
in
mushroom
houses.
Dichlorvos
and
synthetic
pyrethrins
are
the
only
2
available
insecticides
to
control
phorid
fly
adults.
As
phorid
resistance
to
synthetic
pyrethroids
has
been
demonstrated,
dichlorvos
is
the
only
available
alternative.
Dichlorvos
is
currently
used
by
10%
of
growers
in
PA.
Although
only
5%
of
national
mushroom
production
is
currently
treated,
provides
critical
pest
control
for
houses
infested
with
phorid
flies.
If
dichlorvos
is
not
available
for
use
in
mushroom
houses,
it
is
assumed
that
those
Eastern
US
farmers
that
have
phorid
fly
problems
that
require
the
use
of
dichlorvos
(
10%
of
Eastern
US
farmers
per
year)
could
incur
losses
of
as
much
as
$
1.6
million
per
farm,
which
represents
a
30%
decline
in
per
farm
revenues,
due
to
losses
in
the
quality
and
yield
of
the
mushrooms
harvested.
If
resistance
to
synthetic
pyrethrin
continues
throughout
the
industry,
dichlorvos
use
could
expand
to
other
areas.

I.
SCOPE
AND
LIMITATIONS
OF
ASSESSMENT
The
scope
of
this
assessment
is
at
the
national
level
but
relies
heavily
on
data
from
the
2
largest
mushroom
production
states;
Pennsylvania
and
California.
This
mitigation
scenario
is
in
response
to
the
health
risks
identified
by
the
Health
Effects
Division
of
the
Office
of
Pesticide
Programs
for
applicators
in
mushroom
houses.

There
are
limits
to
this
assessment.
The
primary
limit
is
the
lack
of
available
data
associated
with
mushroom
production
(
1996
survey).
In
addition,
this
assessment
is
limited
to
Agaricus
mushrooms
and
does
not
include
specialty
mushrooms
(
shiitake,
oyster,
etc.).
However,
as
a
result
of
different
production
practices
for
specialty
mushrooms,
this
assessment
should
be
reflective
of
enclosed
mushroom
house
production.
This
assessment
ignores
potential
changes
in
production
which
could
occur
associated
with
dichlorvos
availability.
It
is
also
assumed
that
producers
will
not
shift
to
alternate
crops.

II.
MUSHROOM
PRODUCTION
Mushroom
production
can
be
broken
down
into
3
regions
in
the
US:
East
(
CT,
DE,
FL,
FA,
MD,
NY,
PA
and
TN),
Central
(
IL,
IN,
IA,
MI,
MO,
OH,
OK,
TX,
and
WI),
West
(
CA,
CO,
MT,
ND,
OR,
UR,
and
WA)
(
Table
1).
Sales
of
the
2001­
02
US
mushroom
crop
was
851
million
pounds
with
a
sales
value
of
$
911
million,
including
both
Agaricus
and
specialty
mushroom.
Agaricus
mushrooms
accounted
for
98.4%
of
total
mushroom
production.
US
fresh
market
production
was
83
percent
of
total
sales
volume
with
processed
making
up
the
remaining
17
percent.
There
were
262
commercial
mushroom
producers
in
the
US
in
2001­
02,
of
which
129
were
Agaricus
mushroom
growers.
Yields
averaged
5.73
pounds
per
square
foot.
Producers
received
an
average
return
of
$
5.98
per
square
foot.

Pennsylvania
accounted
for
54.9%
of
the
total
volume
of
sales
in
2001­
02
followed
by
California
with
15.3%
of
total
volume
of
sales.
Brown
mushrooms,
including
Portabello
and
Crimini
varieties,
accounted
for
923
million
pounds
or
11%
of
total
Argaricus
volume
sold.

Substrate
preparation,
mushroom
composting,
is
a
process
of
recycling
organic
matter
to
create
a
physical
and
biological
medium
optimized
for
mushroom
production
that
requires
4
­
6
weeks.
The
process
normally
involves
a
2
­
3
week
preconditioning
period,
a
2
­
3
week
windrow
period
with
periodic
turnings,
filling
into
beds
or
trays,
and
the
last
phase
of
composting
that
is
a
closely
managed
process
which
includes
steam
pasteurization
at
140
°
F
for
4­
6
hr.
The
substrate
is
spawned
(
seeded)
and
the
spawn
is
allowed
to
grow
through
the
compost
for
2
wks.
Spawn
is
a
sterilized
cereal
grain,
rye,
millet,
wheat,
etc,
that
is
thoroughly
grown
through
with
mushroom
mycelium.
Spawn
is
produced
in
an
aseptic
building
by
about
a
dozen
highly
specialized
companies
who
sell
their
products
to
mushroom
farmers.

When
the
substrate
is
colonized
by
the
spawn,
a
top
dressing,
a
casing
that
is
made
from
sphagnum
peat
moss
(
or
similar
material)
and
agricultural
limestone,
is
applied
to
the
surface
of
3
the
substrate.
The
casing
is
irrigated
periodically
and
both
temperature
and
carbon
dioxide
levels
are
managed
during
the
4­
10
day
period
required
for
the
spawn
to
reach
the
surface
of
the
casing
and
form
into
small
primordia
of
mushrooms
called
pins
and
buttons.

Table
1.
Area,
Sales,
Price,
and
Value
of
Agaricus
and
Specialty
US
mushroom
production
in
2001­
02
State
Area
in
Production
(
1,000
sq
ft)
Total
Fillings
(
1,000sq
ft)
Volume
of
Sales
(
1,000
lbs)
Price
per
Pound*
($)
Value
of
Sales
(
1,000
$)

East
23,682
96,756
557,417
0.9
503,410
Central
2,476
18,048
103,855
1.39
144,097
West
7,157
31,459
176,594
1.29
227,029
US
33,315
146,263
837,866
1.04
874,536
*
Prices
for
mushrooms
are
the
average
prices
producers
receive
at
the
point
of
first
sale,
commonly
referred
to
as
the
average
price
as
sold.
For
example,
part
of
the
fresh
mushrooms
are
sold
F.
O.
B.
packed
by
growers,
part
are
sold
bulk
to
brokers
or
repackers,
and
some
are
sold
retail
at
roadside
stands,
the
mushroom
average
price
as
sold
is
a
weighted
average
of
the
average
price
for
each
method
of
sale.

Mushrooms
grow
rhythmically,
being
ready
for
harvest
every
5
to
7
days.
Each
wave
of
mushrooms
is
called
a
break
or
flush
with
farms
keeping
the
crop
for
3
breaks.
Harvesting
is
currently
done
by
hand.
After
3
breaks
have
been
harvested,
the
production
room
is
steam
pasteurized,
cleaned
out
and
prepared
for
another
filling.
Each
production
room
is
occupied
by
a
crop
for
10
to
12
weeks
which
means
4­
5
crops
can
be
grown
in
a
room
each
year.
The
standard
production
room
contains
8000
square
feet
of
producing
surface
and
it
is
called
a
>

double
=;
average
production
is
5.8
lbs
square
feet
(
fresh
weight)
per
crop
cycle.

III.
USE
OF
DICHLORVOS
IN
MUSHROOM
HOUSES
Data
for
dichlorovos
use
in
mushroom
houses
is
lacking.
The
registrant,
American
Vanguard
(
AMVAC),
indicated
that
dichlorvos
marketed
for
mushroom
house
use
only
represented
0.31%
of
total
dichlorvos
sales
in
1996.
The
registrant
provided
data
indicates
that
only
424
lbs
were
sold
for
mushroom
house
pest
control
in
1996.
Survey
data
from
1992,
indicated
that
only
3
of
59
(
5%)
mushroom
growers
used
dichlorvos.
Of
the
3
using
dichlorvos,
only
1
grower
indicated
that
dichlorvos
was
a
#
1
priority
at
that
time.
Phone
conversations
with
the
American
Mushroom
Institute
(
AMI)
in
2003
indicated
dichlorvos
sales
in
PA
had
grown
to
10%
of
agaricus
mushroom
producers
representing
5%
of
state
production.

IV.
TARGET
PESTS
IN
MUSHROOM
HOUSES
Dichlorvos
is
used
primarily
to
control
adult
Sciarid
and
Phorid
flies
in
mushroom
4
production.
The
adult
flies
are
attracted
by
the
smell
of
the
substrate
used
in
mushroom
production.
Dichlorvos
can
be
used
early
in
the
crop
cycle
or
at
the
end
of
crop
production.
A.
SCIARID
FLY
Sciarid
flies
are
the
major
pest
in
mushroom
production.
The
Sciarid
fly
larvae
has
caused
major
and
minor
crop
losses
intermittently
at
most
mushroom
farms.
In
addition,
Sciarid
flies
serve
as
vectors
for
disease
causing
organisms,
which
reduce
the
yield
further
and
also
reduce
the
quality
of
harvested
mushrooms,
and
create
a
significant
nuisance
to
the
pickers.
Left
unchecked,
the
Sciarid
fly
will
damage
a
mushroom
crop
by
limiting
the
yield
of
mushrooms
by
as
much
as
70%.

Female
Sciarids
invade
production
houses
as
the
compost
cools
down
after
peak
heating.
The
invasion
continues
during
spawning.
Once
inside,
females
will
land
on
compost
near
the
point
of
entry
and
lay
up
to
150
eggs.
Females
can
detect
residues
of
Dimilin
and
avoid
laying
eggs
on
substrate
with
this
pesticide.
Larvae
hatch
from
eggs
in
4­
6
days
at
regular
compost
temperatures
and
begin
feeding
immediately
on
mycelium
and
the
compost
itself.
Larvae
go
through
4
molts.
Twenty­
one
days
after
egg
hatch,
larvae
forms
a
non­
feeding
pupae.
The
pupal
stage
generally
lasts
about
1
week.

Feeding
of
larvae
in
the
first
generation
probably
does
little
damage
to
the
crop,
except
where
Trichoderma
green
mold
is
prevalent.
In
these
instances,
even
a
small
number
of
flies
can
signigicantly
magnify
the
damage
from
this
disease.
Very
high
numbers
of
larvae
feeding
in
the
compost
during
spawn
run
can
inhibit
fruit
body
production
by
destroying
the
compost
and
the
mycelium.
Crop
damage
and
loss
of
yield
and
quality
may
also
result
from
the
ability
of
sciaried
flies
to
mechanically
spread
mushroom
diseases.
The
feeding
of
the
second
generation
larvae
also
can
be
extensive
and
result
in
yield
loss
through
degradation
of
the
compost
and
casing,
and
destruction
of
mycelium
and
fruit
body
primordia
in
the
casing.
Severe
infestations
may
result
in
larvae
tunneling
up
into
the
stip
resulting
in
a
condition
referred
to
as
A
black
stem
@

which
renders
the
mushrooms
unmarketable.
Left
unchecked,
the
Sciarid
fly
can
reduce
the
yield
of
mushrooms
by
as
much
as
70%.

B.
PHORID
FLY
Phorid
flies
pose
a
threat
to
crop
yields
and
crop
quality
mostly
as
vectors
of
mushroom
pathogens,
both
fungi
and
bacteria.
Adult
phorids
generally
enter
the
production
rooms
and
houses
later
in
the
crop
cycle
than
Sciarids.

Phorids
prefer
warmer
temperatures
and
drier
conditions
in
the
substrate.
Females
lay
about
50
eggs
in
areas
where
there
is
fresh
mycelia
growth.
Eggs
5
hatch
in
several
days
and
larvae
begin
feeding.
Larvae
may
develop
through
3­
4
instars
to
adults
in
only
15
days
in
warm
compost
(
75­
80
E
F).
During
cropping
with
lower
temperatures
(
60­
70
E
F)
in
the
casing,
development
may
extend
up
to
50
days.
Larvae
only
feed
for
1/
3
of
the
development
period
with
the
remainder
spen
as
non­
feeding
pupae.

Because
larvae
feed
selectively,
they
are
not
capable
of
causing
the
kind
of
damage
that
Sciarids
do
as
larvae.
Economic
crop
damage
similar
to
that
caused
by
Sciarids
may
not
occur
until
Phorid
numbers
are
50
to
100
times
greater.
Nevertheless,
Phorid
control
is
necessary
to
maintain
crop
health
as
these
flies
are
capable
transmitters
of
fungal
and
bacterial
diseases.
Phorid
flies
cause
>

fly
speck
=

on
mushroom
caps
which
reduces
the
quality
of
mushrooms
to
the
cull
grade.
Adults
can
also
be
a
significant
irritant
to
picking
crews
and
may
need
to
be
controlled
to
maintain
efficiency.

V.
ALTERNATIVE
CONTROL
A.
INSECTICIDE
ALTERNATIVES
Insecticide
alternatives
for
fly
control
in
mushroom
houses
is
dependent
upon
the
presence
or
absence
of
a
crop.
When
crops
are
present,
only
2
insecticides
are
recommended
for
use.
These
are:
azadirachtin
(
insect
growth
regulator)
and
piperonyl
butoxide
+
pyrethrins
(
adulticide).
Fly
resistance
to
pyrethrins
is
common.
In
the
absence
of
a
production
crop
(
compost
and
casing
only),
6
insecticides
are
available
for
fly
control.
These
include
the
growth
regulators
diflubenzuron,
methoprene,
and
cyromazine.
Adulticides
for
use
in
the
absence
of
a
production
crop
include
diazinon,
malathion,
and
permethrin.
However,
diazinon
application
is
limited
to
the
walls
and
floors
only
and
fly
resistance
to
permethrin
has
been
noted.
Larval
fly
control
using
insect
growth
regulators
in
the
substrate
is
the
preferred
control
strategy.
Outside
perimeter
and
walls
are
also
subject
to
periodic
application
of
methylcarbamate
and
diazinon.

B.
BIOLOGICAL
CONTROL
Mushroom
flies
are
good
targets
for
biological
control.
Some
of
the
agents
which
can
be
used
for
mushroom
fly
control
include
nematodes,
microorganisms,
mites,
fungi,
and
biologically
derived
chemicals.
However,
none
of
these
biological
control
agents
have
proven
as
effective
in
field
situations
as
in
laboratory
studies.
Also,
all
biological
control
agents
have
not
been
successfully
commercialized.

C.
CULTURAL
CONTROL
Cultural
measures
are
a
key
components
in
controlling
flies
in
mushroom
6
houses.
Composting
material
is
steam
pasteurized
to
eliminate
most
insects
and
nematodes
from
the
substrate.
Steam
pasteurization
takes
place
in
a
room
where
the
substrate
is
layed
out
in
beds
or
trays
at
a
depth
of
10
to
18
inches.
Pasteurization
requires
2
to
4
hr
when
the
compost
and
air
temperature
is
held
to
at
least
140
°
F.
The
substrate
containers
are
also
steam
pasteurized
during
this
process.
Outside
air
used
to
manage
the
compost
temperatures
is
filtered
to
minimize
ingress
by
adult
flying
insects
and
fungal
spores.
Fine
screens
over
openings,
caulked
cracks
in
walls
and
ceilings
and
air
filters
reduce
the
insect
threat.
The
threat
to
the
substrate
is
further
reduced
by
minimizing
breeding
and
roosting
sites
of
the
flies
by
mowing
the
grass
and
eliminating
still
water.

D.
SHORTENING
CROP
CYCLE
Any
technique
that
shortens
the
length
of
the
crop
cycle
aids
pest
control
by
reducing
the
amount
of
time
pathogenic
organisms
have
to
reproduce.
The
strategy
is
to
complete
the
harvest
and
pasteurize
the
room
before
pest
populations
can
damage
the
crop.
The
benefits
are
twofold:
first,
when
pest
organisms
enter
a
growing
room,
they
do
not
have
sufficient
time
to
reach
economically
injurious
levels
within
that
crop.
Second,
it
reduces
the
amount
of
innoculum
on
the
farm
for
new
crops
in
other
rooms.
This
applies
to
arthropod
pests
as
well
as
fungal
pathogens.
There
are
many
ways
to
reduce
the
time
needed
for
the
cropping
cycle.
Most
important,
run
the
growing
rooms
properly
from
the
start.
Low
temperatures
or
mechanical
problems
in
spawning
or
casing
can
delay
the
onset
of
picking
and
expose
the
room
to
excessive
increases
in
pest
populations.
Phase
II
rooms
must
be
brought
into
conditioning
range
without
undo
delay.
Cooldown­
tospawning
times
should
be
kept
to
a
minimum,
and
proper
spawning
rates
must
be
used
to
ensure
complete
colonization
in
a
minimal
amount
of
time.
During
cropping,
remaining
mushrooms
from
each
break
should
be
stripped
to
help
the
next
break
come
in
more
quickly.
Growing
techniques
that
shorten
crop
cycles
also
should
be
considered,
such
as
adding
CAC­
ing
(
Compost
At
Casing)
to
the
casing
layer
and
reducing
the
number
of
breaks.
Through­
spawning
and
supplementation
are
examples
of
methods
used
in
the
past
to
shorten
crop
cycles.

VI.
BIOLOGICAL
IMPORTANCE
OF
DICHLORVOS
FOR
MUSHROOM
HOUSES
Exclusion
of
adult
mushroom
flies
from
mushroom
growing
rooms
and
incorporation
of
an
insect
growth
regulator
into
the
mushroom
substrate
have
been
major
factors
in
lowering
crop
losses
caused
by
Sciarid
flies.
However,
adulticides
are
still
important
tools
to
control
Phorid
flies
in
mushroom
production.
Dichlorvos
is
one
of
only
two
adulticides
available
to
mushroom
producers.
Loss
of
dichlorvos
would
ensure
increased
reliance
on
pyrethrins
with
increased
potential
for
insecticide
resistance.
BEAD
concludes
that
although
use
of
dichlorvos
is
low,
dichlorvos
has
a
niche
use
with
high
benefits
for
mushroom
production
due
to
the
lack
of
7
alternatives.

VII.
ECONOMIC
IMPORTANCE
OF
DICHLORVOS
FOR
MUSHROOM
HOUSES
As
discussed
previously,
dichlorvos
is
critical
for
mushroom
growers
for
the
control
of
the
phorid
fly
in
the
Eastern
US
mushroom
producing
areas.
There
is
only
one
alternative
to
dichlorvos
available,
and
resistance
to
this
pesticide
has
developed
in
a
number
of
cases.
As
a
result,
if
dichlorvos
is
not
available
for
use,
it
is
assumed
that
mushroom
growers
that
have
a
phorid
fly
problem
which
necessitates
the
use
of
dichlorvos
(
an
estimated
10%
of
Eastern
US
mushroom
growers
per
year),
will
not
achieve
control
of
the
phorid
fly.
If
uncontrolled,
phorid
flies
pose
a
threat
to
mushroom
crop
quality
by
causing
specking
on
the
surface
of
the
mushrooms,
and
crop
yield,
as
vectors
of
mushroom
pathogens,
both
fungi
and
bacteria.

Adult
phorid
flies
enter
the
production
mushroom
houses
early
in
the
crop
cycle,
and
dichlorvos
is
applied
at
this
time
to
achieve
control
of
the
flies
and
prevent
damage
to
the
mushrooms.
On
average,
there
are
approximately
4
production
(
crop)
cycles
per
year,
with
3
breaks
(
harvests)
per
cycle
in
a
typical
mushroom
house.
If
phorid
flies
are
a
problem
on
a
farm,
it
is
assumed
that
they
will
be
a
problem
for
3
production
cycles
in
that
year
­
with
less
activity
during
the
forth
cycle.
As
a
result
it
is
expected
that
mushroom
growers
would
apply
dichlorvos
3
times
per
year,
once
per
cycle
when
the
phorid
fly
is
a
problem.

Since
the
use
of
dichlorvos
is
estimated
to
occur
only
in
Pennsylvania
(
the
major
mushroom
producing
state
in
the
US),
and
not
in
other
mushroom
production
regions
of
the
US,
we
assume
that
the
phorid
fly
is
only
a
problem
in
the
Eastern
US,
and,
therefore,
impacts
are
assumed
only
to
occur
in
the
Eastern
US
if
dichlorvos
is
not
available
for
use.

Based
on
USDA
data,
there
are
approximately
21
million
square
feet
of
mushroom
production
in
Pennsylvania
and
24
million
square
feet
of
mushroom
production
in
the
Eastern
US.
USDA
data
for
2001/
2002
estimate
that
there
are
88
mushroom
growers
in
the
Eastern
US,
which
produce
an
estimated
558
million
pounds
of
mushrooms,
valued
at
$
503
million
(
at
an
average
price
of
$
0.90
per
pound).
Average
production
per
farm
is
approximately
6
million
pounds,
and
there
is
an
average
of
22
mushroom
houses
per
farm.

A.
IMPACTS
FOR
A
TYPICAL
INFESTED
MUSHROOM
HOUSE
A
typical
mushroom
house
has
4
production
cycles
per
year,
with
3
breaks
per
cycle.
If
dichlorvos
is
not
available
for
use,
it
is
assumed
that
on
those
farms
in
the
Eastern
US
where
phorid
fly
is
a
significant
problem,
the
mushroom
houses
will
likely
face
both
losses
in
mushroom
quality
and
yield
in
each
break
of
a
cycle
in
which
the
phorid
fly
is
active.
Assuming
that
the
phorid
fly
is
active
early
in
a
production
cycle,
the
following
losses
are
expected
per
break
if
dichlorvos
is
not
available
for
use:
8
1.
In
the
first
break
phorid
fly
numbers
are
expected
to
be
relatively
low.
However,
an
estimated
25%
of
the
harvested
mushrooms
will
face
a
loss
in
quality
due
to
specking
on
the
mushrooms
caused
by
the
flies.

2.
By
the
second
break,
phorid
fly
populations
are
expected
to
increase
substantially.
As
a
result,
it
is
estimated
that
as
much
as
70%
of
the
harvested
mushrooms
will
be
lost
due
to
the
rapid
spread
and
development
of
disease
spread
by
the
flies
in
the
mushroom
house.
The
remaining
30%
of
production
would
not
be
damaged.

3.
In
the
third
break,
it
is
expected
that
as
much
as
100%
of
the
harvested
mushrooms
will
be
lost
due
to
the
spread
of
the
disease.
It
is
likely
that
prior
to
this
occurring
(
soon
after
the
second
break),
the
grower
would
abandon
the
house
and
sanitize
the
house
to
rid
it
of
the
phorid
fly,
in
preparation
for
the
next
harvest
cycle.

Assuming
6
million
pounds
of
production,
22
houses
per
farm,
4
cycles
per
year,
and
3
breaks
per
cycle,
there
are
an
estimated
22,750
pounds
of
mushrooms
produced
per
break
in
a
cycle
in
an
average
mushroom
house
on
the
average
mushroom
farm
in
the
Eastern
US
(
6
million
pounds/
22
houses/
4
cycles/
3
breaks).
At
a
price
of
$
0.90
per
pound
of
mushrooms,
the
value
per
break
is
$
20,475.
As
a
result
of
a
phorid
fly
infestation
in
a
house,
based
on
the
assumptions
above,
we
would
expect
the
following
impact
on
production:

1.
In
the
first
break,
as
a
result
a
25%
quality
loss,
5,688
pounds
of
production
would
shift
from
the
fresh
market
to
the
processed
market,
and
receive
the
processed
market
price
of
$
0.30.
The
remaining
17,062
pounds
of
production
would
receive
the
fresh
market
price
of
$
0.90.
The
value
of
production
would
be
$
17,062.
This
represents
a
loss
of
$
3,413
(
or
17%)
from
the
per
break
value
of
production.

2.
In
the
second
break,
as
a
result
of
a
70%
loss
in
yield,
30%
of
production
(
6,825
pounds)
would
be
harvested
for
sale
in
the
fresh
market.
The
value
of
production
in
this
market
would
be
$
6,142,
which
represents
a
loss
of
$
14,333
(
or
70%)
from
the
per
break
value
of
production.

3.
In
the
third
break,
a
100%
yield
loss
is
expected,
so
no
revenue
will
be
earned
for
this
break
in
the
cycle.

The
total
value
of
the
cycle
across
all
three
breaks,
with
an
uncontrolled
phorid
fly
infestation
would
be
$
23,204,
which
is
a
decline
of
$
38,221
(
or
62%)
9
from
the
average
value
of
production
for
a
cycle
($
61,425).
Assuming
(
in
the
worst
case)
that
if
a
house
is
infested
with
phorid
fly
in
the
first
cycle,
2
of
the
remaining
3
cycles
of
a
house
would
face
a
similar
level
of
phorid
fly
infestation
in
a
year,
the
value
of
production
in
that
house
would
decline
to
$
131,037.
This
represents
a
decline
of
$
114,663
(
or
47%)
from
the
value
of
production
for
a
typical
mushroom
house
($
245,700)

A.
IMPACTS
FOR
A
TYPICAL
FARM
A
typical
mushroom
farm
in
the
Eastern
Region
has
an
average
of
22
mushroom
houses.
However,
at
any
one
time,
only
an
average
of
2/
3
of
the
mushroom
houses
on
the
farm
are
in
production.
The
other
1/
3
of
mushroom
houses
are
in
a
non­
production
phase.
As
a
result,
it
is
assumed
that
if
a
farm
is
infested
with
the
phorid
fly,
a
maximum
of
14
houses
could
face
mushroom
damage
from
infestation.
It
is
important
to
note
that
a
mushroom
farm
may
not
have
a
phorid
fly
problem
every
year.
In
fact,
only
an
estimated
10%
of
the
farms
in
the
Eastern
US
are
expected
to
have
a
significant
phorid
fly
problem
from
year
to
year,
and
it
is
not
expected
that
the
same
farms
would
have
a
phorid
fly
problem
every
year,
although
it
certainly
could
be
the
case.

In
the
absence
of
additional
data,
we
assume
that
if
a
farm
has
a
phorid
fly
problem
that
necessitates
the
use
of
dichlorvos,
all
14
mushroom
houses
in
production
on
the
farm
will
face
the
losses
estimated
for
a
typical
mushroom
house
if
diclorvos
is
not
available
for
use
to
control
the
phorid
fly
(
as
discussed
above).
Assuming
revenues
of
$
131,037
for
a
mushroom
house
with
uncontrolled
phorid
fly
infestation,
for
the
14
houses
on
a
farm,
per
farm
revenues
would
fall
to
$
3.8
million
(
assuming
the
other
8
houses
on
an
average
farm
suffer
no
adverse
impacts
to
production
from
the
phorid
fly).
This
represents
a
30%
decline
(
a
loss
of
$
1.6
million)
in
revenues
from
the
typical
per
farm
revenues
($
5.4
million).
10
B.
IMPACTS
FOR
EAST
TOTAL
(
PENNSYLVANIA
AND
OTHER
EASTERN
STATES)

In
2001/
2002
there
were
an
estimated
88
farms
in
the
Eastern
US
(
78
farms
in
Pennsylvania
and
10
farms
in
the
other
Eastern
US
states).
Total
production
in
the
Eastern
US
has
averaged
approximately
558
million
pounds
of
mushrooms
at
a
value
of
around
$
503
million
(
at
$
0.90/
lb).
Assuming
that
only
10
percent
of
these
farms
are
treated
with
dichlorvos
to
control
phorid
fly
in
a
typical
year,
an
estimated
9
farms
will
be
affected
if
dichlorvos
is
not
available
for
use.
These
farms
represents
54
million
pounds
of
mushroom
(
6
million
pounds
per
farm),
at
a
value
of
$
49
million
in
the
absence
of
losses
due
to
the
phorid
fly.
Based
on
the
per
house
and
per
farm
assumptions
presented
above
for
instances
where
phorid
fly
is
a
problem
and
dichlorovos
is
not
available
for
use,
revenues
on
these
9
farms
could
fall
to
$
34
million
(
9
farms
x
$
3.8
million
per
farm),
which
represents
a
loss
of
$
15
million
across
those
9
farms.
As
a
result,
total
revenues
in
the
Eastern
US
would
fall
to
$
488
million,
which
is
a
3%
loss
in
total
revenues
in
the
Eastern
US.

C.
SUMMARY
AND
FINDINGS
If
dichlorvos
is
not
available
for
use
in
mushroom
houses,
it
is
assumed
that
those
Eastern
US
farmers
that
have
phorid
fly
problems
that
require
the
use
of
dichlorvos
(
10%
of
Eastern
US
farmers
per
year)
losses
of
as
much
as
$
1.6
million
per
farm,
which
represents
a
30%
decline
in
per
farm
revenues,
due
to
losses
in
the
quality
and
yield
of
the
mushrooms
harvested.
Assuming
that
only
10%
of
the
farms
(
9
farms)
in
the
Eastern
US
are
expected
to
have
phorid
fly
problems
requiring
the
use
of
dichlorvos
in
an
average
year,
losses
for
the
Eastern
US
mushroom
industry
(
and
for
the
entire
US,
assuming
that
only
the
Eastern
US
has
phorid
fly
problems
necessitating
the
use
of
dichlorvos)
could
be
as
high
as
$
15
million
or
3%
of
the
total
value
of
Eastern
US
mushroom
production
(
or
2%
of
the
total
value
of
US
mushroom
production)
(
see
Table
2).
However,
it
should
be
noted
that
phorid
resistance
to
permethrin
may
increase
over
time
and
increase
the
number
of
growers
impacted
above
the
level
evaluated
in
this
assessment.
11
Table
2.
Estimated
Impacts
to
Mushroom
Growers
Of
Not
Having
Dichlorvos
Available
for
Use
To
Control
Phorid
Flies
Losses
per
House
Losses
per
Farm
Losses
for
the
Eastern
U.
S.

$
114,663
$
3.8
million
$
15
million
47%
decline
in
revenues
per
house
30%
decline
in
revenues
per
farm
3%
decline
in
Eastern
US
revenues
and
2%
decline
in
total
US
revenues
Source:
Agricultural
Statistics
Board,
NASS,
USDA,
Mushrooms,
August
2002.

I.
REFERENCES
1.
Mushrooms.
August
2002.
Agricultural
Statistics
Board,
NASS,
USDA
2.
Crop
Profile
for
Mushrooms
in
Pennsylvania.
January
1999.
USDA.
http://
pestdata.
ncsu.
edu/
cropprofiles/
docs/
pamushrooms.
html
3.
Crop
Profile
for
Mushrooms
in
California.
October
1999.
USDA.
Http://
pestdata.
ncsu.
edu/
cropprofiles/
docs/
camushrooms.
html
4.
Pesticides
for
Agaricus
Production.
Penn
State
University.
Http://
mushgrowinfo.
cas.
psu.
edu/
pesticides_
for_
agaricus_
mushroom_
production.
htm
5.
Proprietary
Survey
Data
­
American
Mushroom
Institute.
1992.
6.
Personal
Communication.
Phillip
Coles.
Giorgi
Mushroom
Company.
7.
Personal
Communication.
Dr.
David
Beyer.
Plant
Pathology
­
Pennsylvania
State
University.
8.
Personal
Communication.
Dr.
Shelby
Fleishcher.
Entomology
­
Pennsylvania
State
University.
9.
Personal
Communication.
Laura
Phelps.
American
Mushroom
Institute.
10.
Pennsylvania
Mushroom
Integrated
Pest
Management
Handbook.
2002.
Pennsylvania
State
University.
http://
paipm.
cas.
psu.
edu/
pdf/
mushroomIPMhandbook.
pdf
11.
Personal
Communication.
Dr.
Cliff
Keil.
Entomology
­
University
of
Maryland.
