The Union and eastern journal. [volume] (Biddeford [Me.]) 1854-1858, 1855-02-02
Frsm prsIe's Raral I.isliissa
WARTS ON PLUM TREES.

Can any one tell ls-and tell us truly
what causes the black excrescences, or warts,
on plum trees, and what will prevent them!
We have heard many answers to these ques-
tons, but have no. yet verified the true one.
The books say the warts are caused by an
insect tha, puucturcs the tree and deposits
an egg, under the bark, which becomes u
worm that does the mischief. We have as
much respect for book learning as most men
bu. more for the facts that occur in our own
experience. We have had plum trees, for
years, in perfect health, and most fruitful =
Four or eve years ago. they began to be af-
aictsd with warts. From that day to this
we have cut them out, or amputated the
limbs, thoroughly, but never, even by the
aid Of glasses, have we been able to find the
worm. or to prevent the progress OF the
trouble. What trees are not oil destroyed
by the warts, are about spoiled by our thor
ough amputatiou,, We have cut and sliced
the warts at every period OF their growth,
rom the green swelling upon the smooth
bark, till they had become rough, black OK.
crescences, and our observations 20 to show
that the circulating sap. within the inner
bark, il from some cause diseased, and that
the vessels being unable to convey it along
the limbs, it forces protubcrances which de-
siroy the life at those points, and are the
cause Of the warts.
We are led to this subject now, by MOTTO
ing an article in the Massachusetts, Plough.
man, OF late, from the reasonable pen of L.
w. HARRIS, the Librarian Of Harvard Uni.
vcrsity. Mr.. II. lays it down as principle,
that "tbo plum tree may imbibe fluids by its
roots, faster than it can exlale the super
auous moisture from its leaves" and thus
accounts for the bursting Of the sap vessels.
II is rational theory. The remedy may be
found, perhaps, in pruning the roots. But
let us hear what Mr.. II. says. We COM
mend his remarks to the plum-lovins reader;
a tree or plant takes in fluid by its
roots, and discharges what is not wanted
through the pores Of the leaves. Ligh, and
heat promote Tho discharge OF the super
fluous moisture by the leaves: cold and rain
check this evaporation. But even during
such sudden transitions from heat to cold,
from dry weather to long storm in May, as
are no, uncommon in our climate, the roots
OF the tree may continue to take in fluid,
while evaporation or 0xhalation of moisture
from the leaves may be checked or suspend.
cd. In this case the tree or plant will DO.
come surchargcd with fuid, and the delicate
tissues Of the newly forming wood and bark
will 10 unduly distended by the continued
pressure. Here and there some Of those
delicate parts may give way so rs to lose
their natural form and their relations to
each other. Now, what do we frd in the
warts Of the plum tree, when they are first
forming. and before they have burst through
the bark, We find that the cells Of the
bark and OF the wood are distorted and en-.
lnrged, and have become rs it were of n
mixed character, or rofintermingled wood and
bark. The plum tree has been called q
gross FEEDER" Itpu,s forth numerous roots,
and Il also has tendency to throw up suck.
ers from its roots. But in careful cultiva-
ton, the latter tendency is checked, and con-
sequently by cutting off all these suckers we
deprive the tree Of somo Of its means for
parting with its superauous moisture. II
the foregoing theory be correct, may we not
restore tho balance between tho roots and
the leaves, or rather between the functions
Of these parts, by severe root pruning. II
we cut or some OF the feeders, shall we not
thereby diminish the supply of fluid Such
has been my practice, and it has met with
good success. The root pruning has been
most conveniently performed in the autumn, !,
in anticipation OF such results as might 30
expected 10 follow from overleeding in the
spring, Yours respectfully,
I. w. HARRIS.
Cambridge. Nov. %, 1854.