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Gypsy
Moth Threat, 2008 - 2009
Gone
for now ... until the cycle
begins again.
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July
10, 2009: The following
information is from Gypsy Moth
News - July 2009 from the Centre
County Gypsy Moth Program.
The
Gypsy Moth has left the County (and
State)
Most of you probably will not be
surprised to hear that the Pennsylvania
DCNR is finding that there has been
a near-complete collapse of the
gypsy moth population in the state.
This is very much what many of you
reported when you filled out the
Gypsy Moth Activity Report on the
county's gypsy moth web site. Many
thanks for your efforts - and for
your unique observations in the
text box. Such surveys are extremely
helpful in getting a big picture
view of what is happening in our
large county.
The
general collapse occurred as a result
of the extremely unseasonal rainy
weather that the whole of Pennsylvania
experienced during late May and
June. On three separate occasions,
stationary fronts parked themselves
over the Ohio valley and poured
rain on us for a whole week. These
were very favorable conditions for
the pathogenic fungus, Entomophaga
maimaiga, to grow from strength
to strength until it killed even
strong, late-stage caterpillars
all over the county.
Long-term
Monitoring
During the current outbreak, many
municipalities were subjected to
a defoliation and Rush Township
was subjected to two before any
control measures were taken. The
main reason that such delays occur
is that during times of no gypsy
moth activity, the county personnel
used in monitoring gypsy moths are
stood down and eventually reassigned
to other duties, with only professional
foresters (mostly DCNR state employees)
left on watch. Even these foresters
can be caught unawares, especially
if a population build-up occurs
seemingly out of synchrony with
when it was expected to rise.
Although
my contract with the county terminates
at the end of July, I would like
to set up a group of 'citizen entomologists'
who would monitor the county for
gypsy moths and would fill out online
surveys each April (for young caterpillars)
and September (for new egg masses).
.
Of
course as well as monitoring the
gypsy moth situation, there will
need to have an action plan on how
to respond to any population build-up.
It is likely that during the initial
population build-up phase there
may not be any state program or
funding available for any local
gypsy moth suppression programs.
In such cases, any suppression measure
would have to be handled at municipality
or county level.
I
will be contacting some of you who
showed a keen interest in the gypsy
moth situation over the last two
years. I would like to get as complete
a geographical coverage of the county
as possible, so that we can monitor
comprehensively.
Karl
Mierzejewski
Gypsy Moth Coordinator
We
want to thank everyone, especially
College Township, who contributed
time and money to the Conservancy
in order to fight the impact of
the Gypsy Month on the Mountain
over the past two years. The
Conservancy still needs your support
though! Please help the Conservancy
by becoming a Friend
of Mt. Nittany
The
Mountain sprayed on May 18, 2009
Helicopter
spraying took place from first light
until around 10 am according to
the Centre
County Gypsy Moth Program.
April
28, 2009: The following
information is from Gypsy Moth
News - April 2009 from the Centre
County Gypsy Moth Program.
"Many
of you may have noticed the emergence
of tiny gypsy moth caterpillars
from their egg masses last weekend.
Over the next week to ten days,
Centre County will be experiencing
the dispersal of these caterpillars
as they blow with the wind on fine
silk threads. The little larvae
are only interested in one objective
- to get to a tree which has their
favorite type of leaf (such as oak
or apple) and start feeding.
Their appetites are miniscule at
this stage and spraying them with
Bt (the biological larvicide that
DCNR uses) is not effective. Because
they eat so little, the chances
of them meeting a droplet of Bt
on a leaf is small, plus they could
exhibit avoidance behavior as they
eat around the dried droplet, which
appears very big to them. Another
reason why spraying is inadvisable
is the possibility of more gypsy
moth being blown in from a different
source which could arrive at a spray
site where earlier-sprayed Bt has
little activity left. (Bt is inactivated
by ultra violet light and nearly
all of its activity is gone a week
after spraying.)
Spraying is most affective once
the caterpillar has reached the
second stage. It still has a small
appetite, so the damage it can do
is very small, yet it is still very
sensitive to Bt and there is a good
chance that it will eat a droplet
of it in the course of its normal
feeding.
Spraying: So when will it take place?
The development of leaves and caterpillars
is very much determined by the temperature.
If this turns out to be a typical
spring, then spraying will take
place around Memorial Day."
April
20, 2009: Centre
Daily Times article called
"Gypsy moths back for another
year" reported on the reemergance
of Gypsy moths in the upcoming weeks..
"Property
owners in the parts of Centre County
still plagued by gypsy moths can
expect to see the caterpillars emerging
from egg masses in the coming weeks.
Centre
County gypsy moth coordinator Karl
Mierzejewski said the state’s
spraying program will likely happen
in mid-May. Landowners who aren’t
covered by the program or who want
to give the gypsy moths a double
whammy can also buy a spraying kit
from a garden store.
"Now
is really the perfect time,"
Mierzejewski said.
Once
the caterpillars hatch from their
yellowish, quarter-sized masses,
they fall to the ground on their
threads and make their way up trees.
The off-the- shelf spraying kits
include burlap to wrap around the
tree trunks that you spray with
the insecticide.
Otherwise,
Mierzejewski said, the caterpillars
climb to the tree tops and wait
until the leaves are big enough
and they’re ready to start
feeding.
He
said he expects the gypsy moths
will start hatching toward the end
of April, although it could be earlier
in warm, dry places.
Aerial
spraying of a biological pesticide
through the state Department of
Conservation and Natural Resources
could take place in mid-May, depending
on how the foliage develops.
Which
parts of the county will get sprayed
has already been determined.
After
blanketing parts of Centre County
for several years, the gypsy moth
population has collapsed in many
places, but is still present in
some areas.
Mierzejewski
said his guess is that the infestation
is ending, in keeping with the typical
gypsy moth pattern of hitting an
area for about three years before
a population collapse.
"Pockets
may need to be treated next year,”
he said, "But it’s not
going to be this area-wide
defoliation we had in 2007 and 2008.""
PDF
version
Jan
29, 2009: Centre
Daily Times article called
"Gypsy moth spraying set for
county" reported on plans for
2009 spraying.
"Centre
County and the state are preparing
for gypsy moth spraying in parts
of the county this spring, although
less land will be covered than last
year.
The
Centre County Board of Commissioners
voted Tuesday to approve an agreement
with the state Department of Conservation
and Natural Resources for the spray
program. Director of Planning and
Community Development Bob Jacobs
said the $137,676 contract is for
more than 6,000 acres at a cost
of $21 an acre.
The
money will come from residents whose
land is being sprayed and municipalities.
Gypsy
moth caterpillars eat the leaves
off oaks and other trees which,
over several years, can cause trees
to die. The population of gypsy
moths in Centre County has been
collapsing, and program coordinator
Karl Mierzejewski said he expects
that will continue.
Last
year's spraying took place at the
end of May. The state contractors
uses Bacillus thuringiensis or Bt,
which only affects caterpillars
in the larval stage that eat sprayed
leaves."
Centre
County Gypsy
Moth News - The Big Picture
The
following information is from Gypsy
Moth News - October 2008 from
the Centre
County Gypsy Moth Program.
"Parts
of Centre County have had gypsy
moth outbreaks for three years in
succession and residents have come
to expect an onslaught in spring,
which they hope will be mitigated
as the helicopters of the state
DCNR spray program fly overhead
spraying their biological insecticide.
So it is not surprising that the
reaction of property owners in the
County's western townships to the
news that they will not need spraying
is one of disbelief that things
have returned to normal. In fact,
this is the usual sequence of events
in a gypsy moth outbreak.
When
talking with federal and state insect
pathologists, they point out that
the environment for any gypsy moth
caterpillars that manage to emerge
is extremely hostile in areas that
have been infested for three years
in a row. All sizes of organisms
are now after gypsy moths: microorganisms
such as fungal and viral pathogens,
parasitoids (parasitic insects that
end up killing the host) and even
predators like birds and rodents
that have adapted their diet to
include gypsy moths.
However
it is the first category, pathogens,
that led to the major population
collapses that we witnessed at the
end of the gypsy moth season this
year in parts of the Centre Region
and western townships. A USDA Forest
Service program conducted in Centre
County this year estimated that
the Entomophaga fungus killed 80%
of the gypsy moth population this
year, and in concert with another
pathogen, NPV virus, caused the
population collapse where gypsy
moth mortality was close to 100%.
However,
Centre County is a large county,
with three quarters of a million
acres of forest. Such a large area
does not behave uniformly to events
like an insect infestation. Over
the last three years we have seen
a west-to-east progression of gypsy
moths and this year it is the eastern
townships which in 2009 will be
experiencing their first or second
gypsy moth outbreak."
Gypsy
Moth Situation in Centre County
- the next (2009) generation
The
following information is from Gypsy
Moth News - September 2008 from
the Centre
County Gypsy Moth Program.
The arrow tag to Mt. Nittany was
added by us.
"The
map below shows the areas that are
more likely to have infestations
next year based on a month-long
survey that I did in the county,
counting new egg masses which develop
into the next generation. The color
ramp shows relative egg mass densities,
with white indicating no egg masses
(or very small numbers below the
DCNR treatment threshold) and increasing
redness showing increased egg mass
densities. Because I was primarily
surveying land parcels based on
users' spray requests, the sampling
was by no means evenly distributed
across the county. The gray areas
on the map indicate parts of the
county which were not surveyed because
there were no requests for spraying.
The
main trend for next year is that
the gypsy moths have moved east
and south and have mostly left the
western municipalities except for
an area in south Taylor Township.
So the ‘hot' areas next year
will be in the eastern townships
as well as southern ones which prior
to 2008 had not experienced an outbreak.
Clinton County, which borders Centre
County's eastern boundary, will
experience a major upsurge in population
next year.
There
are some small residual gypsy moth
populations in areas previously
infested in the Upper Bald Eagle
Valley Region (Worth, Huston and
Union Townships), many of which
meet DCNR treatment thresholds of
250 egg masses/acre. Homeowners
who have requested spraying will
most likely be sprayed. However,
it is my estimate that unless it
is a very dry spring which aids
the survival of caterpillars, many
of the areas that have such low
populations will not suffer any
major defoliation next year if left
unsprayed."
Gypsy
moth on the Mountain - July 28,
2008
The
following information is from Alan
Cameron, MNC Board Member and Penn
State Professor Emeritus of Entomology.
"Yesterday
Jule and I took a look at the top
of Mt. Nittany to see what is happening
with respect to the gypsy moth.
We did the white blazed trail only.
I saw maybe as many as half a dozen
females still laying eggs; few males
were seen; flight is almost over.
The
good news is that the spray job
this year was, for the most part,
very effective. Not only did trees
not suffer defoliation, but gypsy
moth larvae were killed. This was
especially evident on the ascending
trail from Mt. Nittany Road. We
saw no new egg masses as we hiked,
and there is only very light defoliation
evident in a few places. On the
top of the Mountain, however, the
story is a little different. The
area generally to the north-east
of the eastern junction of the Blue
blazed trail coming back from the
Mt. Nittany School/Boalsburg viewpoint
suffered moderate to heavy defoliation.
[Standard definitions of defoliation
levels are as follows: 'light' -
<30% leaf surface lost; 'moderate'
- 30 - 60% leaf surface lost; 'heavy'
- >60% leaf surface area lost.
Heavy defoliation normally triggers
refoliation in August, an additional
physiological drain on the tree.]
This area suffered some of the heaviest
defoliation on the mountain last
year, and is the area in which I
found the greatest numbers of egg
masses last summer.
There
is an area on the top of the Mountain
(the moderate to heavy defoliation
this year) where I expect to see
additional tree mortality over the
next few years. These trees were
not especially healthy going into
this summer, and I will be surprised
to see at least some of them refoliate
this year - they are essentially
dead now but just don't know it.
Some trees are obviously dead, and
some of these should be dropped
for public safety purposes. I saw
a few dead larvae hanging in the
typical posture that indicates that
they died of the virus disease.
That is good news. As reports become
available on egg mass counts on
neighboring ridges, we will be in
better position to speculate on
how much blow-in of dispersing larvae
there may be next spring.
It
surprised me at this time of year
how many of the old egg masses remain.
Over the next months, they will
weather away, as should the old
pupal cases. To the untrained observer,
the very large numbers of old egg
masses that persist could give a
false sense of the potential for
defoliation next year.
I
have attached three photos from
yesterday, all taken on the top
of the Mountain in the area of greatest
concern."
This
image shows Moderate to Heavy
Defoliation.
This
image shows Heavy Defoliation.
This
image shows one new egg mass
(the one that is reddish-brown)
along with numbers of old (hatched;
from 2007) egg masses and old (2007)
pupal cases still remaining on the
tree.
The
Mountain being sprayed May 15, 2008
The
following are additional links with
information about the Gypsy Moths
and their impact to the Mountain
collected by the Conservancy since
Fall 2007.
June
18, 2008:
The
Centre County Gypsy Moth Program
website includes "2008
Gypsy Moth Outbreak: The Big Picture".
This report says the following:
If
you supported our spray efforts
this spring, the Conservancy is
very grateful for your help! As
the County and DCNR discuss gypsy
moth suppression program plans for
2009, we will be there to ensure
that our Mountain is protected.
May
14, 2008:
The Mountain was sprayed with the
biological insecticide, Bacillus
thuringiensis (Bt), comprised
of naturally occurring Bacillus
spores. No chemical insecticides
were used. The
Conservancy again thanks all our
Friends that have supported us during
of fund raising campaign for this
spraying.
April
29, 2008: The
Daily Collegian printed an
article called "Moths
to be sprayed." The
article states
in part: "Gypsy moths,
which hatch in late spring, cause
massive defoliation and can wipe
out many of the mountain’s
trees. If nothing is done by August,
Mount Nittany will be leafless,
Woodhead said."
April
23, 2008:
The state Bureau of Forestry announced
plans to triple its aerial spraying
effort to suppress the woodland
insect pest. See "DCNR
to begin spraying woodlands to combat
gypsy moth damage." The
article states "Nine helicopters
and five fixed-wing aircraft will
begin the spray program in early
May and end shortly after Memorial
Day. Spraying is dependent on weather,
foliage development and caterpillar
development; progress can be tracked
at www.dcnr.state.pa.us/forestry/spray.aspx."
April
3, 2008: Penn
State's Daily Newswire had an article
called "Gypsy
moth management made more efficient,
cost-effective."
Feb
25, 2008: WPSU's Pennsylvania
Inside Out discussed the Gypsy
Moth Threat (starts at 3:30). The
segment featured Alan Cameron, Penn
State Professor Emeritus of Entomology.
Watch: Pennsylvania
Inside Out: This is THON, Gypsy
Moth Threat, Koyannisqatsi
Nov
16, 2007: The
Daily Collegian printed an
article called "Conservancy
prepares for gypsy moth damage by
'selling' Mt. Nittany."
This article starts: "A
menacing creature is lying in wait
on the branches of trees lining
Mount Nittany, and Penn State alumni
could help fend it off."
Nov
6, 2007: Centre
Daily Times article called
"Gypsy
moths threaten Mt. Nittany",
the stage is set for heavy defoliation
not only on top but also on the
highly visible sides of our beloved
Mountain in 2008.
.jpg)
Centre
County Gypsy Moth Program:
For more information on the Centre
County Gypsy Moth Program, you can
visit this website: http://www.co.centre.pa.us/gypsymoth/default.asp.
Their site includes a link to Health
Facts. Here they explain
that the biological insecticide
called B.t. or B.t.k
for Bacillus thuringiensis var kurstaki
will be used in the spraying program.
Centre
County Township sites:
College Township - Our
Mountain Needs Us
Ferguson Township - Gypsy
Moth Spraying Information
Halfmoon Township -
Gypsy
Moths page
Patton Township - Gypsy
Moths page
Gypsy
Moth Images: See the
Gypsy
Moth section of the Forestry
Images website. Be sure to scroll
down to the "damage" photos.
