The Western news. [volume] (Libby, Mont.) 1933-current, 1943-06-24
Plagued By
Thousands Of
CdterpiNdrs
Countless HOrdes of
NauSeOus Worms
Attack Trees Here.
COME IN SIX TO
SEVEN YEAR INTERVALS

one of the heaviest visitations of an
obnoxious pest ever experienced
here. Countless thousands of tent
caterpillars are found on many of
the leaf trees of the district and
they are scattered generously all
over the city.
They made their appearance IN
the early spring and are so numer-
Gus in some instances that they
have left the trees and are seen
crawling up the sides of the houses
In some instances they lang by
their silken threads from the
branches of the trees. Last week one
Libby woman started out with her
baby for walk but noticed on
one street that the worms, hanging
over the sidewalk from the shade
trees, were so numerous that she
turned back.
The worms feed on the leaves
of the trees and seem to favor cot
tonWoods, aspins, willows and fruit
trees, especially apple trees. They
can be controlled If taken in time.
When they first appear the tWig
holding the clusters of worms can
be cut off and the pests destroyed.
Another way is to make torch and
burn them as they cling to the twig.
Still another way is to spray the
tree with a poison But this must be
done before the worms grow large
enough to scatter.
These worms are the western tent
caterpillar and not the army worm,
as some suppose. A Department of
Agriculture bulletin says the cat
erpil1ars appear in May and June,
constructing tents of webbing in
the crotches or about smaller tWigs
and leaves of the trees. The cater
pillars feed voraciously during the
day, devouring all the leaf tissue
except the midribs, and retire at
night to the tents, or collect in
masses on the larger limbs. These
caterpillars occur sporadically and
in some years are numerous enough
to defoilate not only fruit trees but
wild growth and shade trees as
well.
The insect passes the winter in
the egg stage. The eggs are laid in
masses surrounding the tWigs, each
mass containing several hundred
eggs covered with a frothy, water
proof broWnish material. The young
caterpillars appear about the time
the apple buds begin to open. The
group Matching from single egg
mass constructs a small silken nest
or tent, and as the caterpillars
grow this nest is enlarged to pro-
vide adequate protection for the
colony.
The caterpillars are somewhat
hairy, taWny brown, with row of
blue spots thanked by orange spots
along the back. When full grown
they are nearly two inches long. AS
the caterpillar becomes larger they
tend to scatter, and their cocoons
may be spun in various sheltered
places, such as under loose bark, in
curved leaves, or under projecting
caves of buildings. The cocoons
are tightly woven of yellow silk.
The moths emerge in June or July
and soon deposit the Wit4tefiffg egg
masses.
Control Methods
Many of the egg masses may be
found and destroyed when the trees
are pruned. If the small caterpillars
are numerous, a spray of lead arse
nate, pounds to 100 gallons, ap-
piled just before the trees bloom,
is very effective If the spraying is
done later, the quantity of lead
arsenate should be doubled, as the
larger caterpillars are more resist
ant to the poison. Very often the