Richmond dispatch. [volume] (Richmond, Va.) 1884-1903, 1895-07-14

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may be. there Is no doubt whatever apoo.
its relative position, as II clearly peionss
70 the round-headed timber-borers, OF 'ne
family Of beetles known to entomoios's's
as the cerambycidae. This famiy in
cludes many OF the most destruc,'. Ia
sects TO finest ornamental or orenaIu
trees. The examination or the pa'h
made this day more than confirms my
former impression Of the serious nh'ule
OF this attack. In fact. l am simply ap-
nailed at the extent OF the injury aireauy
done. and what yet lies I'm store ior the
beautiful park system of the CITY, unless
some practicable means OF checking their
further progress can be devised.
With these preliminary remarks, oes
10 submit the following statement CON
corning the ilfe-history OF the species'
which, with but slight modihcatiohs' WILL
l think, hold good:
The mature beetles begin to issue from
the damaged limbs and trunks OF the
trees during the early part OF June anu
think more than probably continue "
issue, 1p until late summer or early
autumn. In this stage they do no Marin
to the trees, and think eat nothing 10
speak OF. but are solely concerned III
egg-laying, which probably begins In TWO
or three days from the time they issue
and lasts for period Of one or two
weeks. The eggs are deposited by the
females I'm the crevices Of the bark. usu-
ally thrust under out Of sight, and II
appears she confines oviposition 10
branches or trunks from one inch In ol-
ameter up to about three inches.
am quite certain from the known
habits OF this family Of beetles That egg
laying occurs only at night, and hence
the beetles are seldom or never seen
upon the trees They usually lie hid
he fo1f In,
daytime The eggs hatch in few days
from four to ten-and the larvae or gruDs
bore into the bast tissues, and there
spend the first year, becoming about one
fourth of an inch long. The second year
they bore into the solid wood and acquire
a length of about one half an inch. Inc
third year they continue and bore the
solid wood, usually in the heart or the
limb or trunk, making, however, several
openings through to the outside, which
they carefully close up with wood hbres.
These latter openings serve for exit or
the image. The reason for closing them
I'D temporarily is TO prevent the entrance
OF parasites, which might destroy the
larvae.
When three years are nearly completed
the grubs, having attained length some
what above one inch, transform TO pupae
and in q short time issue as full grown
~,
1t is very important in the destruction
OF insects to first get as clear an under
standing of their life history as may be,
as in this manner we may ma some
weak point which we can attack. How
ever. in this case, the statement above
set forth Is not reassuring. III VIII De oD-
served: First, that from the time or
oyipos!tlon until the beetle issues, three
years latter. this species Is entirety hid
from view, and consequently cannot be
reached by any ordinarily applications
used as insecticides; second. that the ma
ture beetles do not eat the foliage or other
tissues. whereby they may be reached
with pOlsons; third, they do not congre-
gate upon the trunks, where they can be
reched by destructive applications, such
as oils, etc, nor can they be found so
as 10 be destroyed by hand in any appre-
ciable numbers. This practically leaves
but one other suggestion in the way or
topical applications-viz, repellants to
deter the beetle from opposition. IL Is,
however, my opinion, from experience
with insects OF this sort, that repellants
cannot be made practicable because of
the very large surface Of limbs and trunks
to be covered: of the rough nature OF the
bark which will prevent any Application
from adhering smoothly over the attacked
surfaces, and also from the fact that all
repellants which can be used practically
on such n large scale are evanescent IN
character. e.. will retain their efficacy
but for a few days at most.
From the foregoing, 1t will be evident
that / do not believe remedial measures
I'm the usual acceptance OF the term TO be
practicable. / have been thus full be
cause / DO not wish II 10 appear that
would give advice % such serious and far
reaching consequences as that which fol-
lows without weighing fully the facts OF
the case and the interests involved.
beg now TO state that IL IL my firm be-
lief that the only remedy lies along he
line of destroying the trees in whole or
In part, and pursuing a system In regard
TO future planting which shall somewhat
mitigate the evil.
RECOMMENDATIONS.
I. Careful inspection should be made
TO establish how far this insect has pene-
trated into the city, both along the streets
and in the parks proper
=. Cut down and burn all elms which
are dead or show any considerable per-
centage of dead limbs This should be
done at the earliest possible moment.
g. Where trees have a fairly healthy
appearance, permit them to remain this
season; but during the coming winter and
spring cut away every limb which shows
signs Of borer and burn them.
4. All young elms which show signs of
borers upon the trunk should be cut down
and burned at once.
5. No young elms should be planted
within the infested limits of the city I'M
til the attack is fully checked.
Respectfully submitted,
WILLIAM d. ATWOOD.
Entomo,ogist, Agricultural Experiment
Station, Blacksburg, Va.