The Washington times. (Washington [D.C.]) 1901-1902, 1901-08-25
TO PROTECT SHADE TREES.
DIR. L. o. Howard Offers Sugges-
tions on the Subject.
The EntomOIogist of the Agricultu-
raj Department Tells How Defolfa-
ton May he Ayerted In Washing
tOn-Insects That Cause Havoc.

The beautiful shade trees of Washing
| ton are in a fair way to become defoli
| ated. 1t is not the common caterpillar
| that Is doing the most mischief this year
but an ubiquitous little creature that re
joices in the psuedonym of thyridupteryI
| ephemeraeformis. or bagworm.
| DR.. l.. o. Howard. Entomoiogist of thu
| Department of Agriculture. when ques
| toned as to the kind of insect which il
| working such havoc in the yerdure of thu
parks and public places of the Nationa
Capital. stated that this did not seen
to be as bad a year for caterpiilars a:
usual. Discussing the question he salt
that most of the defoliation was due t.
| the bagworm. which seems to have Wis
| tied Washington in greater force thi:
: summer than for some years. This rath
| er exclusive insect has the habit of spin
/ ming a web or bag about itself so thai
| it may be safe from the attacks of birds
| and other enemies of insect life. The
| time to efficiently combat the depreda-
lions of this insect, DIR. Howard says, has
| passed for this summer.
THE best time to spray the trees, Dr.
Howard says. lis in the spring. Paris
green should be used a good way to get
| rid of the insect is to go over the trees
in the fall or winter when the branches
are bare and remove the bags.
Besides the bagworm. which is sc
much in evidence this year, some OF the
most relentless insect enemies of leaf life
are the elm leaf beetle, the white-marked
tussock moth. and the fall webworm-
The elm-leaf beetle is net to be so gen.
orally feared as some of the insects nam
ed, because as far as is known no other
tree than the elm is attacked, the common
English elm being the favorite variety.
The beetle makes it's winter home under
the loose bark of trees or in the cracks
of boards or telegraph poles, and in the
former case as soon as the buds begin to
break forth in the spring begins to feed
upon the leaflets. They feed until the
leaves are nearly grown. and then the fe-
males lay their eggs. which are deposited
on the lower sides of the leaves, being
sometimes arranged in two or three irreg-
ular rows. In about a week the larvae
are Matched and begin operations at once
on the inside of the leaf, which they soon
reduce to a skeleton If left undisturbed.
The most satisfactory spray to be used
against these insects Is paris green. lon
don purple, or arsenate of lead. and the
best time is Just after the buds have
conducted two weeks later and a second
and a third and fourth may be necessary.
especially IL heavy rains have fallen.
The Mathematical tussock moth will at
tack almost every variety of shade, fruit,
and ornamental trees. having an appar-
emit preference for the soft naples, pop
lars, elms, alders, and birches,
The female moth lays the eggs in Sep
TENDER. and it is in the egg state that the
insect passes the winter In Washington
the caterpillars hatch in April or May.
After the insect has gorged himself for
four or five weeks he begins to spin a CO.
coon of delicate grey silk. Within a few
hours after the completion OF the cocoon
the larvae are transformed to pupa, and
remain in the pupae condition about two
weeks.
Upon emerging from the pupae condi-
ton the adult insect presents the phenom-
enon of an absolutely wingless female and
a winged male, in this respect resembling
the bagworm.
A remedy advised by the Department
OF Agriculture to destroy the eggs of
these insects is creosote oil. to which
turpentine Is added to keep It liquid in
cold weather, and tar to blacken it so
that treated egg masses can be recog
nized easily. This mixture can be daub-
ed on the eggs by using a sponge at the
end of long pole. The liquids recon-
mended for the slaughter of the elm leaf
beetle are also recommended as sprays.
The webworm is an almost universal
feeder, the records of the Division OF En-
tomology showing about 40 species of
trees attacked by the insect. Spraying
with arsenical poisons and collection of
the cocoons are two remedies advised.
The authorities who control the selection
OF shade trees for parks and streets gen.
orally make their choice with reference
to rapidity of growth and amount of
shade produced. The maple and the box
elder answering these requirements are
introduced in great numbers. But the
maple and the box elder are of all yarie-
ties, most susceptible to insect destruc-
ton. Among the large shade trees the
different species of oaks appear to be most
immune. Washington is unfortunate in
that the shade trees lining TIE streets and
those in the parks are under the same
control. The appointment OF forester
and an entomologist to supervise the care
OF our shade trees would, it is claimed,
be wise move on the part of the Dis
trict Board.
~ lSSueu Dy the OK
Agriculture contains the following re-
marks on this subject:
"A most excellent plan was urged by
one of the Washington newspapers in the
summer of 1894. 1t advocated a tree-pro-
lection league. and each issue of the pa
per through the summer months contain
ed a coupon which recited briefly the de-
of protecting shade trees against
3 bA Of tins md .,
signer as a member of the league. pledg-
ing himself to do his best to destroy the
injurious insects upon the city shade
trees Immediately adjoining his residence.
This is only one of several ways which
might be devised to arouse general inter
est.
THE average city householder seldom
has more than half dozen street shade |
trees in front of his grounds, and 1t
would be matter of comparatively little
expense and trouble for any family to
keep these trees in fair condition. 1t needs
only a little intelligent work at the prop
er time. 1t means the burning of the web
of the fall webworm in May and June; it
means the destruction of the larvae OF the |
elm leaf-beetle about the bases of elm
trees in late June and July; 1t means the
picking off and destruction of the eggs |
of the tussock moth and the bags of the |
bagworm in winter. and equally simple |
operations for other insects should they |
become especially injurious. What a man |
will do for the shade and ornamental |
trees In his own garden he should be |
willing to do for the shade trees ten feet |
in front of his fence"
The Modern Broom,