The Marietta journal. [volume] (Marietta, Ga.) 1866-1909, 1905-10-26

siye. however. that the bark-beetles
first attack weakened and dying trees,
5ut often when numerous, turn their
attack to trees which are apparently
in good health. AS appropriately stat
ed by J. NJ. Stedman, 1T is very large
ly matter of opinion when one pro
noun2es a tree perfectly healthy that
has become infested with this pest,
but no doubt one should regard tree
as healthy when there is absolutely
no reason to suspect anything differ
ent except that it has now become at
tackled by this insect"
Description-Tne adult fruit-tree
bark beetle is a small cylindrical bee
tie, about one-eighth incn in length,
and only about one-third as broad.
They are uniformly black in color,
except the tips of the elytra or wing
covers and portion of the legs which
are dull red. The young borer or
grub-less than one-fourth inch in
lengths white, except for the brown
head.
Winter Stage and Life History-The
winter is passed by this insect in the
larval or grub stage in their channels
under the bark. In spring, about the
middle or latter part of March, the
parent beetles eat their way out from
under the bark making little holes
scarcely One-sixteenth of an inch in d.
ameter. These parent beetles soon
commence to bore into the trees. and
begin the construction Of an egg cham
Der which is nearly always formed in
the direction of the long axis of the
limb, or nearly so. They seem to pre-
fer to enter at the base of the limbs.
or at the forks made by the lateral
spurs, and often at the base of buds
near the extremeties of the small
branches. The beetles are frequently
found, on badly infested trees, enter
ing the trunk nearly to the base of the
trees. The egg chamber is formed
partly in the cambium layer and part
~ in the wood directly beneath. The
egg chambers vary from one inch or
less to an inch and half in length.
and as 1t is formed minute side peck
cts are constructed to each side. in
which eggs are deposited. 1t is sup
posed that each female lays about 80
eggs. The minute grubs Matching from
these eggs burrow at right angles to
the egg chamber When a limb is
badly infested these channels cross and
re-cross one another, until the can,
blum layer of bark. and the wood inst
beneath, is reduced almost to powder
Inc young grubs continue to feed as
described until full grown when they
make slightly deeper burrow and
there change to the pupae from which
emerge the adult beetles as already de
scrtPed. These beetles escape nv sim
ply eating their way out through the
Dark, making the characteristic round
hole AS each beetle must make a
hote through which to escape and an.
other when entering to construct tle
egg chamber, the great number of
NOES found in an infested limb are
easily accounted for.
Generations Each Year-Concernip
the number of broods in Georgia each
year, no definite observations have
peen made. In Missouri Professor
Stedman found three and sometimes q
fourth. Considering the fact that
many adults were observed this wear
during the early part of July. and that
these must have been the third brood
II Is reasonable to predict that we
nave four generations to contend with
IN the peach orchards of Georgia.
Remedies.
Clean Culture-As heretofore stated
the bark-beetles seem to prefer To
breed in dying trees. Herein will he
to'nd the clew to a remedy, or more
properly speaking, prevention. All
dead and dying trees should be destov-
ed by burning during winter. This work
must be done at least before the first
OF March in order to DESTROY all the
young borers alternating under the
bark. All adult trees-it is generally
supposed-die during winter, hence if
all wood containing young borers is
destroyed, there will be practically
no borers left to re-infest the orchard
the following spring. OF course there
Will always be a few slightly infested
trees left, and from them some admit
borers will develop. A small nam.
Der OF adults in March may increase
to considerable numbers by the time
the second and third broods appear
IN aGcjton to burning all brush and
deaG trees during winter, the orchards
saouId Dc closely watched during sum.
mer and when infested trees are dis
covered or even single infested limbs
they should be removed and burned
FertlIizins and OBSERVATION-DISCLOSURES
INFESTED trees will sometimes recover
alter the attacked portions have been
removed To aid this recovery the or
chadist SHOULD cultivate and fertiltze
as appears necessary to keep the trees
III a healthy yiSorOuc state 10 $3.50,