The Portland daily press. [volume] (Portland, Me.) 1862-1921, 1878-07-08
AGRICULTURAL.
The Pine Tree Rorer

Prof. A. ], Cook, of the Michigan Agricul-
tural College, has been making careful inves-
legations upon the borer which so seriously
Injuries pine timber in Northern Michigan,
and gives the result in letter to the Detroit
Post and Tribune, from which we condense
the following:
These insects only attack trees that are
dead, or dying. Neither in green, vigorous
trees, nor in the boards obtained from them,
airs found the tunnels which make the lum-
Der worthless, and which served the destruc-
tive grubs as homes. But let fire or other
cause sap the vigor of the trees, and almost
Immediately the seeds of destruction are
sown, and this, too, whether the trees are
still standing, or are feled to the earth,
whether they are scattered about the forests
or are piled high on the sideways. counted
as many as 20 of these tunnels in sections
less than one foot in length, of medium-sized
trees, which were killed by fire the first week
OF the preceding June. Some blocks which
brought home for our museum show three
of these deep broad tunnels cutting through
an area OF less than two square inches. On
the section burned over in June, 1877 it was
rare to find tree, or even section of tree
one foot long, that did not show the large
clean-cut holes of these borers.
These beetles are of two species: but as
they are very similar in their natural history
and appearance, and almost identical in Their
habits, they need not be separately described.
They are grayish black, very trim, and pecu.
liar In possessing autenn@ attaining livery
great length in the males, while in the fe-
males they are about the length of the body.
These reach in graceful curves from the head
The beetles appear certainly in May and
September, and think, without question, in
July. The spring beetles lay their eggs, each
to the number of about 200, in the crevices
OF the rough bark, during May and early
June, and from these will develop insects
which will come forth as mature beetles The
next spring. The summer beetles deposit
their eggs in July, and the autumn beetles
will in like-way sow the seeds for crop Of
beetles the succeeding autumn.
The beetles, at whatever time they come
forth, emerge froma circular hole, which is
as true and as nicely formed as ii cut with a
bit. This circular opening, the only part oil
the tunnel cut by the mature beetle, is from
one.half inch to an inch deep. The beetles
come forth from their tunnels at any time Of
day or night, and may be seen in great mum.
bers upon the tree-trunks, whether the latter
are down or standing. The courtship and
honeymoon over, the females deposit their
eggs on such trees as are still covered with
bark, and only on those that are dead or dy-
ing.
In few days the eggs hatch, For the first
third OF their lives the grubs remain just un-
der the bark, eating only the outer sap.wood.
found, May 22d, three wel-marked sizes OF
the grubs. The smallest were three-fourths
of an inch long and had not bored deepIv at
all into the wood. I supposed these to have
come from eggs laid the previous September.
The second in size were-one and one-fourth
inches long. These had bored to quite a
depth, though not so far as to seriously dam
age the lumber. suppose these had deyel-
oped from eggs laid by the July brood of bee
ties. The larger ones were one and three
fourths inches long, had eaten often a foot
deep, and had then turned and come again to
the surface by different course, cutting the
timber so badly as to greatly lessen, if not
wholly destroy, its value for lumber. MANY
OF these grubs had already assumed the pupa
state, while not few had fully matured and
were coming forth as beetles. think thew
came from eggs which were laid the previous
spring.
Mr.. Cook adds the following conclusions:
1. Trees, so long as they are kept green
and vigorous, are safe from attack.
q. Trees burned or cut in August are, I
Ihink, sale from injury during the same sea-
son, but should be sawed or got into the wa
ter the next spring.
d. Trees cut or killed before August will
need attention the same season, and if killed
in June are very liable to serious damage.
A. Trees cut or killed can still be saved,
either by peeling off the bark, or by immer-
sion in water.
s.. Cutting the bark from off the top of
the logs only will be effectual, think, as it
causes the bark to peel off. Dampuess will
not destroy the borers, but if exposed to the
not rays OF The sun they die at once.
q. Feeling off the bark not only secures
insure against fire, in case little pains is ia
ken to remove the bark short distance from
the logs.-Coanry Gentleman.