The ranch. [volume] (Seattle, Wash.) 1902-1914, 1905-10-15
THE FIELD
The Fall Web-Worm Tree Pest
&c. A. Popenoe.)

lars about an 1ncn and quarter long,
covered with long, white hairs, and
spinning, for the protection of the col
ony in which they live, a dirty, white,
silken web, covering, when fully de-
veloped, the entire terminal portion
of the branch infested. This insect is
the fall web-worm, known for many
years as tree pest in lawn and
orchard, but more abundant and at
tracing more attention than usual last
year and this.
Observations by the Kansas expert
ment station establish the fact that in
the southern region the insect is two
brooded, and hence more troublesome
than in states farther north, where but
single brood is matured in season.
Its life history is in brief as follows:
The parent insect is a white moth
about an inch in extent of wings. IL
appears in April and May from pupae
which have passed the winter under
rubbish and in loose soil at the foot
of the trees in which the caterpillars
of the preceding autumn had fed
These moths, which are night fiers,
fly, after mating, to the trees and lay
eggs in clusters on leaves mostly in
open spaces and at the tips of the
branches. The young caterpillars are
social and remain for most of their
growth in the colonies Matching to-
gether. On Matching they at once be-
gin to spin webs for protection, and
as the worms grow and extend their
feeding grounds the webs are extended
to correspond, until they attain the
size of a foot or considerably more in
dimensions, depending upon the size
Of oo1>
ly shred the leaves, but later the en-
tire leaf is eaten, and while at the
time of the attack of the more abund-
ant fall brood the tree is so far ma
tured that no great injury to it's vigor
results, the presence of the worm is
very disagreeable, especially when, as
nearly full grown, they begin to crawl
more widely, scattering over trunk
and neighboring porches, fences and
walks. The mature caterpillars de-
scend the tree and hide under matted
leaves or other rubbish, or in hollows
and crevices, or in the loose soil to
the depth of an inch or Whereabouts.
Here they enter the dormant pupa
stage, in which they remain until the
latter part of July or the first part of
August, when they change into moths.
These soon after lay eggs, as did the
earlier brood, and unless the first
brood of caterpillars was greatly re-
duced by disease or parasites, the
August brood is vastly more numerous
and propOrtionately destructive. In
one summer colony over six hundred
moths matured. Others are almost
entirely destroyed by parasites, of
which there are two forms. Two
winged flies, much like house flies in
general appearance, are abundantly
bred from some colonies. Four-winged
flies, known by the general name of
braconids or ichneumon flies, are, how
ever, more widely effective, and are
frequently reared in great numbers.
The late generation of caterpillars
have habits like the earlier except
that, entering their dormant state
later in the season, they remain there
in until the next spring, when they
hatch into moths by which the eggs
for the early colonies are deposited.
Most common shade and orchard
trees are subject to the attacks of
these pests. They are specially fond
of elm, box-elder, hickory, ash, apple
and plum trees, but scattered colonies
occur in various other trees.
Owing to their Matching in dense
colonies it is comparatively easy to
check their multiplication and prevent
the appearance of the disgusting webs
by destroying the caterpillars when
young. They are mostly to be sought
for at the tips of the branches toward
the open, and when discovered they
may be removed for destruction or
destroyed where they occur. In the
latter case kerosene torch will cook
them, with little injury to the branch,
or spray of arsenical poison may be
applied. These methods should be re.