PANDORA
MOTH
4
J
A
nfestations
of
pandora
moth
{Colomdia
pandora)
periodically
de-
foliate
trees
in
forests
and
urban
landscapes
in
central
Oregon.
.
Pandora
moth
larvae
(caterpillars)
feed
primarily
on
the
needles
of
ponderosa
and
lodgepole
pines,
and
they
cause
severe
growth
loss—even
tree
death.
This
publication
provides
information
on
identification,
life
cycle,
and
control
methods
for
pandora
moth
for
home
and
forest
owners.
Stephen
A.
Fitzgerald,
area
Extension
forestry
agent,
central
Oregon
(Deschutes,
Crook,
Jefferson,
and
Grant
counties
and
Warm
Springs
Reservation),
Oregon
State
University.
ORGGON
STATG
UNIVGRSITY
GXTGNSION
SGRVICG
'l
EC
1383
•
February
1992
Identification
Adults
are
large,
heavily-
bodied,
grayish-brown
moths
with
a
wingspan
of
2.5
to
4
inches.
Fore-
and
hindwings
have
a
distinctive
black
spot.
Hindwings
are
rose-colored
(figure
1).
Male
moths
have
large,
yellow,
featherlike
antennae;
female
antennae
are
also
yellow,
but
not
featherlike.
Newly
hatched
larvae
have
shiny
black
heads
and
black
or
brownish
bodies
with
short,
dark
hairs.
Larvae
are
about
1
inch
long
in
late
fall
(figure
1)
and
may
grow
to
1.5
inches
by
late
winter.
By
early
sum-
mer
the
next
year,
larvae
are
about
2
inches
long,
yellow-
ish-green
in
color,
with
a
few
stout-branched
spines
on
each
body
segment.
Life
cycle
The
pandora
moth
requires
2
years
to
complete
the
four
stages
of
its
life
cycle:
egg,
larva,
pupa,
moth
(figure
2).
Adult
moths
appear
in
June
or
early
July.
Most
of
the
moths
fly
at
night,
but
male
moths
can
often
be
seen
flying
around
during
the
day
in
search
of
mates.
When
populations
are
high,
moths
can
some-
times
cover
the
sides
of
buildings,
swarm
around
streetlights,
and
become
a
nuisance
to
homeowners.
Eggs
are
laid
in
July
and
August
on
foliage,
bark,
and
the
sides
of
buildings
and
other
structures.
The
young
larvae
hatch
in
late
August
and
September
and
climb
up
into
trees
and
begin
feeding
on
needles.
During
winter,
the
young
larvae
hibernate
in
clusters
at
the
base
of
needles.
During
mild
winters,
they
may
periodically
resume
feeding
on
warm
days.
At
this
early
stage,
the
caterpil-
Figure
1.
—
Pandora
moth
(above)
and
caterpillar
(below).
lars
are
difficult
to
see
and
often
go
unnoticed.
The
larvae
resume
feeding
in
early
spring
(March-April)
of
the
next
year,
and
continue
feeding
until
late
June
or
early
July.
Caterpillars
then
move
down
the
tree
and
burrow
in
the
soil,
where
they
form
a
pupa
(transform
from
caterpillar
to
moth),
and
remain
through
winter
and
spring.
In
late
June
or
early
July
of
the
second
year,
the
adult
moths
emerge
and
mate
to
complete
their
2-year
life
cycle.
Population
cycle
Pandora
moth
infestations
build
up
to
epidemic
propor-
tions
over
several
genera-
tions.
Studies
in
Arizona
showed
that
pandora
moths
increase
from
endemic
(low)
to
medium
or
high
levels
after
one
or
two
generations
(2
to
4
years).
The
population
continues
to
increase
for
a
total
of
three
or
four
generations
(6
to
8
years)
before
the
population
crashes,
which
usually
happens
when
the
population
becomes
in-
fected
by
a
naturally
occurring
virus.
Tree
symptoms
and
impact
The
larvae
feed
on
needles
in
the
fall
of
the
first
year
and
spring
and
early
summer
of
the
second.
In
spring,
on
heavily
defoliated
trees,
crowns
(area
of
live
foliage)
can
appear
thin,
and
the/re
sometimes
totally
void
of
needles
because
the
old
foliage
has
been
consumed
and
new
needles
haven't
yet
emerged
(figure
3).
Trees
are
refoliated
because
new
growth
occurs
immediately
after
defolia-
tion
and
because
trees
have
a
chance
to
grow
new
needles
the
next
year,
when
the
insects
are
pupating
in
the
soil
and
no
feeding
takes
place.
Severe
defoliation
can
be
rather
spotty,
with
severely
defoliated
tree
clumps
as
large
as
30
to
40
acres
(figure
3).
Severely
defoli-
ated
trees
lose
vigor
and
diameter
growth
is
reduced.
Nevertheless,
trees
seldom
die
outright
from
pandora
moth
defoliation.
However,
defoliation
in
combination
with
other
stress
factors,
such
as
mistle-
toe,
drought,
competition
from
other
trees,
and
physi-
cal
damage
can
lead
to
tree
death.
Severely
defoliated
trees
could
be
at
increased
risk
from
bark
beetles
attacks,
including
mountain
pine
beetle
{Dendroctonus
ponderosae)
and
pine
engraver
dps
pini).
Figure
2
Pandora
moth
has
a
2-year
life
cycle.
Direct
control
No
insecticide
is
specifi-
cally
registered
for
the
control
of
pandora
moth
in
Oregon.
Studies
in
Arizona
found
that
the
insecticide
Orthene
was
useful
in
controlling
pandora
moth
in
the
fall
(October)
of
the
first
year,
when
larvae
are
in
the
early
developmental
stages.
There
are
several
other
broad-spectrum
insecticides
that
may
be
useful
for
controlling
pandora
moth
caterpillars
around
the
home
and
in
forested
areas.
Consult
your
county
office
of
the
OSU
Extension
Service
for
a
list
of
appro-
priate
insecticides.
Remember:
Always
read
and
follow
label
directions!
Homeowners
who
want
to
spray
trees
on
their
prop-
erty
may
want
to
hire
a
tree
care
professional
with
equip-
ment
capable
of
spraying
tall
trees.
This
will
ensure
even
and
thorough
coverage.
which
improves
control.
Spray
only
when
caterpil-
lars
are
visible
and
actively
feeding.
Because
pandora
moths
are
attracted
to
light,
you
can
prevent
attracting
them
to
your
property
by
keeping
outside
lights
off
until
the
moth
flight
is
over.
Figure3.
—
Caterpillars
eat
the
older
needles
ofponderosa
pine
trees
(right),
and
they
can
completely
defoliate
an
entire
stand
(below).
__________
mam
Life
Stage
Moth
Caterpillar
Pupa
Yearl
Year
2
I
Moth
Flight
Moth
flight
Lay
eggs
on
trees
and
buildings
First
and
second
Instar
3rd,
4th,
&
5th
Instar
Light
feeding
on
needles
Above
Ground
Crawl
down
tree
to
soil
Emerge
from
pupa
chamber
elow
Ground
C?
Burrow
below
duff
and
litter
and
pupate
in
mineral
soil
Stay
below
ground
12
months;
no
feeding
I
I
I
I
I
I
I
I
ONDJFMAM
I
I
I
I
I
I
I
I
I
I
I
JJASONDJFMA
Months
M
I
I
J
J
I
I
A
S
Mountain
pine
beetle
Because
defoUated
trees
may
be
at
greater
risk
to
mountain
pine
beetle,
you
may
want
to
use
a
preventive
insecticide
to
reduce
the
chance
of
beetle
attack.
To
provide
1
and
perhaps
2
years
of
protection
against
this
pest,
there
are
pesticides
that
you
can
apply
to
the
trunk
of
defoliated
trees
in
the
spring.
See
EC
1085
for
more
information.
Since
this
treatment
is
expensive,
spray
only
high-value
trees,
such
as
those
in
home
landscapes
and
in
campgrounds.
Improving
tree
recovery
after
defoliation
When
heavily
defoliated,
trees
use
a
considerable
amount
of
energy
to
regrow
new
needles.
This
depletes
food
reserves
and
reduces
the
tree's
ability
to
withstand
other
stresses,
such
as
insects,
disease,
and
drought.
You
can
take
several
steps
to
speed
recovery
and
boost
tree
vigor
under
varying
levels
of
defoliation.
Home
owners
If
you're
a
homeowner,
you
may
want
to
spray
the
affected
trees
to
prevent
further
defoliation.
In
addition,
if
the
defolia-
tion
is
severe,
you
may
want
to
fertilize
affected
trees
to
improve
their
vigor.
Use
a
fertilizer
high
in
nitrogen.
This
treatment
provides
the
necessary
nutrients
for
the
tree
to
regrow
its
needles.
For
proper
coverage,
fertilize
outward
from
the
base
of
the
tree
to
three
times
the
radius
of
the
tree's
crown.
For
example,
if
the
radius
of
the
tree's
crown
is
4
feet,
evenly
apply
the
fertilizer
out
to
12
feet
around
the
tree.
This
ensures
the
entire
root
system
is
fertilized.
You
can
use
granular
fertilizer
and
fertilizer
"spikes";
they're
sold
in
most
farm
and
garden
stores.
For
specific
fertilizer
rates,
see
your
county
Extension
agent.
Forest
owners
If
you're
a
forest
land-
owner,
spraying
and
fertiliz-
ing
an
entire
stand
of
trees
is
costly.
If
defohation
to
your
trees
is
light,
no
special
treat-
ment
is
needed
nor
practical.
If
your
stand
of
trees
is
severely
defoliated
(that
is,
most
of
the
needles
cosumed),
you
may
want
to
consider
thinning
the
stand.
Thinning
provides
more
water,
nutrients,
and
sunlight
to
the
remaining
trees
and,
there-
fore,
improves
tree
vigor.
However,
wait
to
thin
your
stand
until
the
follow-
ing
year
after
defohation,
so
the
trees
have
time
to
regrow
their
needles.
This
will
also
make
it
easier
for
you
to
determine
which
trees
have
survived.
When
you
thin,
select
the
most
vigorous
trees
in
your
stand,
providing
a
16-
to
18-
foot
spacing
between
leave
trees.
Trees
that
are
vigorous
generally
have
the
largest
crown
area
(green
foliage)
when
compared
to
other
trees
within
the
same
stand.
Good
candidate
leave
trees
should
also:
be
straight,
have
good
form,
and
be
free
of
other
insects,
pests,
and
disease.
For
further
reading
Capizzi,
Joe,
Mountain
Pine
Bark
Beetle:
Protecting
Individual
High-Value
Pine
Trees,
Oregon
State
University
Extension
Service
Circular
1085
(CorvaUis,
1981).
No
charge.
This
publication
(and
the
one
you're
holding,
EC
1383,
Controlling
Pandora
Moth
in
Central
Oregon
Forests
and
Landscapes,
75t)
are
available
from
Publica-
tions
Orders,
Agricultural
Communications,
Oregon
State
University,
Adminis-
trative
Services
Bldg.
422,
CorvaUis,
OR
97331-2119.
Shipping
and
handling
For
orders
up
to
$3.50,
please
include
50c.
For
orders
between
$3.50
and
$100,
include
15%.
For
orders
of
$100
or
more,
or
for
100
copies
or
more,
call
Agricultural
Communica-
tions
(503-737-2513)
for
a
quote
on
reduced
shipping
and
handling
rates.
Use
pesticides
safely
•
Wear
protective
clothing
and
safety
devices
as
recommended
on
the
la-
bel.
Bathe
or
shower
after
each
use.
•
Read
the
pesticide
label—even
if
you've
used
the
pesticide
before.
Follow
closely
the
instructions
on
the
label
(and
any
other
directions
you
have).
•
Be
cautious
when
you
apply
pesticides.
Know
your
legal
responsibility
as
a
pesticide
applicator.
You
may
be
liable
for
injury
or
damage
result-
ing
from
pesticide
use.
This
publication
was
partially
funded
by
monies
from
the
Stewardship
Program,
Oregon
Department
of
Forestry.
The
Stewardship
Program
is
part
of
the
Forest
Stewardship
Act
of
1990.
Its
purpose
is
to
stimulate
integrated
management
of
other
natural
resources
with
timber
on
nonindustrial,
private
forest
land.
Extension
Service,
Oregon
State
University,
CorvaUis,
O.E.
Smith,
director.
This
publication
was
produced
and
distributed
in
further-
ance
of
the
Acts
of
Congress
of
May
8
and
June
30,1914.
Extension
work
is
a
cooperative
program
of
Oregon
State
University,
the
U.S.
Department
of
Agriculture,
and
Oregon
counties.
Oregon
State
University
Extension
Service
offers
educational
programs,
activities,
and
materials—
without
regard
to
race,
color,
national
origin,
sex,
age,
or
disability
—as
required
by
Title
VI
of
the
Civil
Rights
Act
of
1964,
Title
IX
of
the
Education
Amendments
of
1972,
and
Section
504
of
the
Rehabilita-
tion
Act
of
1973.
Oregon
State
University
Extension
Service
is
an
Equal
Opportunity
Employer.
