We found Gypsy Moth caterpillars on all of our oak and cherry trees last
night.  At dusk, they came from the base of the tree and started marching in
hordes up the trunk.  We killed hundreds of them.  Apparantly they stay in
the hostas and the periwinkle at the base of the tree and march up each night
to munch on the leaves.  I put a ring of malathion 50 around each tree and
that stopped any more from marching up (at least for the time being).

We have since found them in abandoned birdhouses, and any other crevice or
blind holes near the trees.  

If you have trees you want to protect, go out near {ark and shine a flashlight
up and down the trunks.  If you find them, toss them in a bucket of soapy
water and it will do them in.  

The female moth can not fly.  It just broadcasts pheremones and the males find
them.  They lay egg masses on the tree trunks and in almost any recessed
areas.  The egg masses look like a yellowish white fuzzy patch about 3/4"
long.  

29 responses total.

What does the Gypsy moth caterpillar look like?

They have yellowish "tufts" coming off each body segment, and yellowish
lines running down their backs.

And they are large. We have just discovered an infestation in Eberwhite Woods.
It is the first one.

This item has been linked from Nature 64 to Intro 81.
Type "join nature" at the Ok: prompt for discussion of
insects, trees, and other living things.

What do they do that makes them a pest?

They defoliate the trees - nearly totally. *Some* people also don't
like the droppings. It sounds like it's raining in a forest being defoliated
by gypsy moths. Trees can usually withstand one or two defoliations, but
many are killed if it is repeated more often. 

Well, here's my personal experience with the Gypsy moth caterpillars.  We
found hordes of them crawling up 4 trees among about 100 trees.  (Three
infested trees were oak, one was black cherry).  The oak trees were all about
18-24" in diameter.  We did not see any on small oaks.  We killed all the
caterpillers we could find by tossing them into a bucket of soapy water.  We
kept at it until about 1 hr after total darkness when no more seemed to be
climbing.  The next night, we found only a dozen or so total.  The 3rd night,
we found one.  No more have been seen.  It looks like you can wipe out an
infestation with a few night's work.

We also found several pupae and some egg masses.  Be especially careful of
abandoned birdhouses, or holes in your trees.  They seek these types of
shelters.  

Good luck, it may be about time for all the caterpillars to pupate.

One thing which I don't understand is how they expand their territory.  The
females don't fly.  The males find them and mate with them, followed by egg
laying.  

The larvae climb up a different tree. That spreads them locally, but
the major means of spreading them today is by people's vehicles. The
egg masses are laid on trailers and campers and cars, and carried 
elsewhere. Their spread has actually been very slow, and would have been
slower if people weren't such a big "help".

The naturalist at Oakwoods Metro Park said that they 'spin' a thread (sort
of like a spider), catch a breeze, and get carried to the next tree.The
prevailing wind direction determines the way they move through a stand of
trees. They move on, the damaged trees (that can) recover, or new growth
starts.  

I had forgotten that. I now recall seeing them descending on their silk
thread. Do they come down every night, and climb again in the morning? 
I can imagine them being blown into adjacent trees, while hanging on their
thread, but I didn't think they spun a thread while staying on the tree
so that the wind would pick up the thread and then carry them along (like the
"balloon" spider does). 

They don't float, as much as swing to the next tree. The park system
doesn't have any sort of eradication program. They figure the moths will
just pass through and move on. Anyway, they can only reach so far up the
tree to remove the eggs, and will miss most of them.

Things are coming together.  Early this summer I noticed thousands of
caterpillars on the bottom side of branches on a huge maple tree we like
to sit under at Silver Lake.  There were also a few chrysalis hanging 
from the branches.  Caterpillar poop kept coming down on us...  A week or
two later most of the caterpillars were gone and there were lots of
chrysalis and lots of moths.  There were also lots of birds in the trees
going for lunch.  Bird poop was a bit of a problem for a few of us...
 
Are these things really moths?  They are very un-moth-like in that they
fly around in the day time.
 
A couple three weeks later I noticed that all the moths fluttering about
was done with and there were now much lighter colored moths all over the 
branches and trunk with egg masses behind them.  How can such a tiny
moth produce such a *huge* egg mass!  Indeed, they can not fly.  I pryed
several females off with some difficulty and they can't even flap their
wings.  I feel sorry for this tree.  There were tens of thousands of
egg masses plastered all over it.  I also found that the caterpillars
do not come down to the ground at daylight.  They simply camp out on the
under sides of branches during the day.
 
Some city workers also came by our house early this summer and they hung
a Gypsy moth trap from one of our maple trees by the street.  I have only
seen a few Gypsy moth caterpillars around our property but that trap has
a steady stream of moths going to it during the day!

It's been a year and we are about through another Gypsy moth cycle.  I've
plucked several hundred off of various tree around the our yard.  Even
the Huge Maple at Silver Lake is still alive :-)  Several parts of the city
and even a few trees out in the country look like they are stuck in
winter, with only a few wisps of green leaf remains to show they are alive.
 
Yesterday, however, I noticed *lots* of dead caterpillars on the tree
trunks.  When you touch them with a stick, the skin will often easily 
break.  I wonder if this is the fungus, I read about, that attaks them?

They have a specific virus which kills something like 30% of the eggs and a
variable percentage of caterpillars, depending on their population density.
They also have a bacterial killer which occurs naturally and is sold
commercially.  

In my trees, I have some which are killed by an insect which is shaped like
a stinkbug but has a beige to black hard shell back.  I can't identify the
beetle in my insect book, but it does the job.  

After reading the literature, it sounds really depressing if we are hoping
to save the oaks.  Apparantly over the long haul, the oaks will disappear and
they will be replaced with a variety of maple.

The Oaks are going to be in big trouble if the infestation goes on for a few
years. There are ancient Red and White Oak trees in Eberwhite Woods and
Pioneer Wodds, and many of them are 100% defoliated.

I have a pin oak tree growing on the lwn extension. It is a favorite of the
caterpillars. Earlier in the infestation, I was removing more than a hundred
caterpillars every day from that one tree, with the help of the burlap.

I am still taking about 20 off twice a day, but we are nearing the end, as
you say. I hope next year won't be worse, but I fear it will. Fortunately the
pin Oak has been doing pretty well due to my agressive defnese of it. Just
munched a little around the edges.

"The situation is likely to be the same in Michigan (As Northeast) over the
next 100-150 years.  Oaks may become less common, while red maples may become
more common.  This shift in species composition should make our forests more
resistant to Gypsy moth.  Although outbreaks will continue, gypsy moth
caterpillars may be less abundant during outbreaks"

From:  Gypsy Moth In Michigan - Extension Bulletin E2302 - Mich State Univ
Extension and Dept. of Entomology.

From what I was reading in the paper, Gypsy Moths even eat evergreens!

From the same MSU article:

Trees and shrubs most at risk to defoliation:
All Oak
All aspen and poplar
gray, paper (white) and river birch
All willow
All apple and crabapple
All thornapple and hawthorne
White pine
Blue Spruce
American beech
Basswood
Sweetgum
Juneberry or serviceberry
Witch hazel
Hazlenut
Mountain ash 

They also have lists for "somewhat at risk" and "at minimal risk".

Also in this article:

"Unlike hardwood trees, conifer (evergreen) trees cannot refiliate and cannot
tolerate complete defoliation.  Conifers store most of their energy reserves
in the needles, rather than in their roots like hardwood trees.  When needles
are consumed by gypsy moth caterpillars, no energy reserves are available to
produce more foliage and the tree will die."

I know that they will kill pine trees in one year. I wasn't aware that 
they would go after blue spruce.  They will prefer oaks and other 
hardwoods to these until they run out of food. 

I have a blue spruce which I have been watching for caterpillars, and 
there are Scotch pine in the woods adjacent to my property, but none of 
these have been eaten this year. The Oaks will come back, possibly 
refoliating in a little while, but definitely again next year, except 
for diseased ones. Even they can't stand defoliation repeatedly for more 
than a few years, though.

If the little buggers go after my spruce I am calling in heavy artillery 
(persistent insecticides). I can't control the caterpillars on that tree 
mechanically with burlap and daily caterpillar removal like I can with 
all my other trees.

Yesterday a city forester came by and asked my wife if she could move
the car parked out in the street.  He wanted to hang another Gypsy Moth
trap in the Maple they had hung one in last year.  Last year that trap
had captured the most moths in the area: 850 of them.  Others and
caught 600 or less.
 
I've also noticed that many caterpillars have now shed their skin and
are now chrysalis.  I've removed several from our house where the base-
ment meets the siding and inside corners of door and window frames.
Some are huge while others are a third the size.  I wonder if the large
ones are the females and the smaller ones the males?  I also though 
that butterflies came from chrysalis, not moths.  I need to research
this more!

The large tan ones that fly are the males. The females are white, a little
smaller, and cannot fly. 

There are now egg masses visible on most of the trees in infected areas.
These are tan dime to quarter-sized patches. If you decide to remove these,
you should scrape them off and put them in soapy water to kill the eggs.

I am not removing egg masses in the woods, because there are way too many,
and they need to get counted by whoever is doing that. 

A year has gone by and the gypsy moth caterpillars are back in larger
numbers this year.  At this moment they are from .3 to 1.25 inches in
length.  I had removed all the egg masses I could find last year but
it didn't seem to help much.

Last nigh I wrapped two wires, spaced about .3 inches apart, around the
trunk of a walnut tree infested with them.  I then connected the two
wires to an electric fence charged I got at a garage sale for $1.  It
seems to be very effective.  When a caterpillar crosses the wires, there
is a snap from a spark and the caterpillar goes limp.

My neighbor called the City Forester when he noticed the sides of his
house covered with caterpillars.  They said to use some nasty poison that
is toxic to humans and requires on to burn any clothing that comes into
contact with it.  I hope his wife and I talked him out of using it!

So that's what's been defoliating my roses....

I have one oak, but only a few caterpillars.  Not having any burlap, I wrapped
duct tape sticky side out a few times around the trunk.  I was expecting a
flypaper effect, but the caterpillars actually don't want to try to cross it.

This year in Eberwhite woods the caterpillars are way down thanks to the
spraying of BT just as they emerged. I think it was very effective. Some of
the trees that were defoliated last year have  failed to leaf out this
spring. We are talking about 100 foot tall oaks, and they may be gone.
This is despite the claims by experts that they should be able to survive
several years of defoliation. 

I am pleased that the caterpillar population control was attempted.
I nevertheless continued to burlap my vulnerable trees, and to extract
caterpillars manually and drown them in soapy water on a regular basis.
The season for this is almost over. 

I have been doing the same.  Thousands of them.

We would have had thousands too, if they hadn't sprayed with BT. 
I have stopped with the burlap now. No more caterpillars have appeared 
on any of my trees in days.

In areas unprotected by the spray, they are probably pupating by the 
zillions now.

I haven't seen one all summer and did nothing to stop them since there
weren't any. In fact, all of our trees seem to especially like this
Spring/Summer, as they are full, green, and free of pests.

We have moths fluttering about all over!  When the city came to place a
second moth trap in the Maple in out front yard my wife went
out and talked to them.  She was told that our area was one of the harder
hit areas (Miller & Newport).  I was surprised that they didn't spray our
area.  (However the kids spotted helicopters equipped with spray bars in
the area so I suspect that we were close to the line.)

Does anyone know what a small striped bug is that has completely defoliated
our Japanese lanterns and the closely related ground cherries this year?  Sort
of a dull greenish brownish yellowish nondescript thing.  Never saw it before.

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