Savannah morning news. [volume] (Savannah) 1868-1887, 1884-09-14

| ezs sssss GO article, not necessarily
ioSp ads0.s-As.S, but as evidence of good
issA2-
inYcEusaN32 the Pear Blight.
That drea6e1 1;ssase, the pear blight.
has for years Ia lei investigation. and
ignorance OF its nRtIc9 has enabled it to
destroy somo of the aest valuable or
charcis in the country In a bulletin is
sued byt he New XoEx Experiment Sta
ton, Prot. j. g. Arth K. the botanist,
stated that in order to rare experiments
which would enable him arrive at a
correct knowledge Of the AZURE of the
disease he secured afeW diseased branches
from an infected orchard, an Ia nong them
was one with viscid, yelloUiEi5 rOps ex-
uding from the stem. He paEoS-red sew
eral healthy trees, about an ineEf Sora the
eXtremities, with needle, insot.iRg
small quantity of the excretion. In Assut
six or eight days every branch which lad
been inOculated showed unmistables izas
of blight. The bark turned brown, an
then black about the punctuTe, gradually
extending through the stem, passiAg I'D
ward toward the end of the branch mucl.
faster than downward or around the
branch. On the ninth day most of the
wounds eXuded some of the same Viscid
fluid which was used in the first place.
They were all removed on the thirteenth
day to prevent the disease securing any
permanent hold on the tree. Most of the
infected branches were blackened for a
foot or more, and the young tender leaves
as well, all being dead. It was noticea-
able that the full-grown leaves were rarely
affe ted and generally remained green up
to tue time of the removal of the branch.
Among the leaves inOculated only one be-
came infected, and this was young and
tender one. The disease from tspread to
the stem and worked the same as in the
other cases. At the same time portion
OF the same virus was applied to two
young apple branches. Both showed the
disease in eight days. 1t spread gradually
until, on the thirteenth day, akSut two
IL che 5fron the apex was quite dead and
dry, and The branches were removed.
The virus was prepared by cutting up
an inch or so of diseased pear stem in a
glass half full of water, and after stirring
the chips about in the water the chips
were all removed, which left the water
slightly milky. This was used on several
kinds off ruit trees by making Rpuncture
with pin and inoeulatlng a small drop
from the glass. Sufficient time has not
elapsed to show full results, but very
young branch eft he JEnebsYry Showed
signs OF he blight on the sixth day.
Some experiments were made and re-
the fruit OF Bsrtlett pear trees with t he
watery infusion. Or the sixth day they
were all blackened for some distance
Rro1ndt he point OF incubation ard eT.
uding copious how Of yellowish fluid,
which ran down from the side and dropped
on the ground. Upon cutting them open
they were found dscolored almost
throughout their interior. Tests on
ounce trees showed the disease in seven
days, but without any exudation, while
only one-fourth of the interior was af-
feeted.
The conclusions arrived at are that the
disease known asst he pear blight is infec-
tious and may be transmitted from one
tree to another by incubation; that it is
not confined to the pear tree, but may at
tack other pOmaceOus fruits, such as the
apple, ounce, English hawthorn and
Juneberry; that it is most active and
progresses most rapidly upon you lg and
succulent portions of the tree. Under the
microscope any bit of diseased tissue
shows nc0nceivable myriaoa of minute
bacteria, which ell the wate-o the slide
in which it is mounted like cloud. 1t
is, therefore, not necessary. depend on
| external appearances in cpAsr to deter
mine the progress of the disease in a
branch, as the microscope will decide
with absolute certainty, The bacteria
are, without deubS the cause Of the dis
| ease.
New that he oR=ss of pear blight is
| thoroughly unders!8oS the matter of pre-
venting its spread az arresting its dam
aging work will be easier, as further in
vestigation will no doubt supply remedy
| in that Gireetion.--Philddelp Record.