Oxford Democrat. [volume] (Paris, Me.) 1833-1933, 1905-01-31
The Brown Tail Moth.
WHY A SIEGE FROM 1T WOULD BE
MORE SERIOUS THAN PAST CATER
PILLAR INvAsIONS.

A few wears ago parts of Maine wei
Ioyerrun with the forest tent caterpillar
Trees were stripped, people were wo
|ried-but the whole experience is sti
too vivid in the memory of the observer
to need detailed discussion here. Th
point is, that army of forest tent cate
pillars disappeared. allow did it hal
pen?" as there any reason to thin
the caterpillars of the brown tail mot
will be any more destructive than tn
others?' "Are they likely to last an
longer?' 1t is in reply to constantly n
curing questions of this kind, asked 9
the Maine Agricultural Experiment Sta
tion. that Miss Patch, the station entt
mologist, has prepared the following:
The forest tent caterpillar has man
natural enemies. There are tiny para
sites that attack the eggs, and there ar
larger parasites that breed in the cater
pillars. There are many birds that pic
at the egg clusters, feed greedily upO
the caterpillars, and eat the moths
Besides these there is a contagious dis
ease which has commonly appeared
| where the forest tent caterpillars hav
become very numerous which destroy
them by the thousand.
Under ordinary conditions the fOres
tent caterpillar and its natural enemies
keep fairly we'll balanced. Enough o
the moths escape through egg, caterpil
lar, and moth stage to propagate tn
species. Enough of the parasites ant
other enemies are at work to keep TIT
caterpillars from getting numerous. Yea
after wear this state of affairs continues
the caterpillars gaining little one sea
son. perhaps, only to be driven bacl
within bounds the next. All this time
man pays no heed-caterpillars, birds
braconids, tachina flies, ichneumon file,
and disease fight their battles unObserv
ed in forest and orchard and roadside
tangle.
After a while, however, things may
ret unbalanced. Perhaps so many para
sites have haunted q certain vicinity tina,
all the caterpillars have been killed and
the succeeding generation of parasites
must seek hosts elsewhere or die with.
out depositing eggs. In consequence
there would be thinning out of the
parasites in this vicinity and if moths OF
the forest tent caterpillar fly into this
place and deposit eggs, the caterpillars
stand a pretty good chance of thriving.
One hundred and fifty eggs for moth
to lay is a very conservative estimate.
Suppose ten moths find this favorable
spot and most of their descendants
should develop and deposit eggs, the
next season would find about 225, 600
caterpillars there. Perhaps in another
district the climatic conditions are such
that the caterpillar disease has not ap-
peared and there are a few hundred
thousand healthy caterpillars there.
Perhaps in a third locality something
has happened to thin out the black birds
and other insect eating birds and the
caterpillars have increased rapidly there.
When some such conditions as these
cases suggest become general, when
the caterpillars are at high tide and
their natural enemies are at ebb tide,-a
caterpillar plague results, such as oc-
Cured in Maine few years since, and
people taken by surprise ask, where
have they come from?'
Then the parasites fly from one colony
where they are numerous to Others and,
SO long as their hosts are plentiful, in
crease enormously in numbers. Disease
starting in one locality spreads widely.
After a season or so the caterpillars have
thus disappeared, and again people,
equally astonished ask, "Where have
they gomez"
No living thing is entirely exempt
from natural checks. But 1t sometimes
happens that so far as mans interests
are concerned these checks are decided
ly insufficient. No one, for instance,
dreams of leaving the potato beetle to
natural enemies!
The history of the brown-tail moth
differs from that of the forest tent cater
pillar. Even in Europe, its native
haunt, natural agents have not proved
capable of holding the pest in check,
and for more than one hundred years in
some European countries laws have been
in force making it obligatory on the peo-
ple to destroy winter nests.
1t is net uncommon that an imported
pest (e. G., English sparrow, white weed,
orange hawk weed, etc. is more serious
in its new surroundings than it is on its
native ground, condition explained
sometimes, by the fact that the land to
which it migrates lacks some OF the
checks which have acted against it else
where.
About seven years ago there were only
n few colonies of the brown-tail moth IN
Eastern Massachusetts, where it was in
PRODUCED. This winter the alternating
colonies are thick in southern Maine
and scattered colonies occur at least
half way down the coast line OF this
state. Massachusetts, has already suffer
cd a severe infestation from this poison
GUS and destructive caterpillar. The
threat hangs heavily over Maine-a
threat against our orchards, our forests,
our summer resorts, and our comfort and
health.
With more than a centnry's standing
in Europe and steady and appalling In
crease for the past seven years IN New
England there is no reason to suppose
that the brown-tail moth will be con-
trolled by natural causes. The history
of the forest tent caterpillar has CON
cerned chiefly the caterpillar and its
natural enemies. The history OF the
brown-tail moth has so far concerned
the pest and man. This insect is most
admirably equipped for the siege. 10
be met successfully it must be fought
with utmost vigilance. There is, fortu
nately, one practical vulnerable point.
The burning of each winter nest puts
colony of $50 or more young caterpillar:
to death. Each nest, left undestroyeo
this winter, liberates early next spring
the same number of poisonous caterpil
lars to ravage until into the summer
when they undergo the change to the
egg LAYING moth form (white winged
and brown tailed, subsequently, to blow
wherever the wir ds list or to fly where
ever lights attract.
There is no law concerning the brown
tail moth, and no state or town oflcia
has any authority in the matter. In
diyidual action of each citizen is neces
sary to check this insect. Collect dnt
burn every nest and the brood is external
mated. A special bulletin of the Main'
Agricultural Experiment Station de
scribes the brown-tail moth and cop.
will be sent on application.
CHAs. D. WOODS,
Director Maine Experiment Station.
ORoNo, January, 1905.