The ranch. [volume] (Seattle, Wash.) 1902-1914, 1904-04-15

as working havoc in orchards for
century or more, it is only in compar-
atively recent times that its true ma
ture has been well understood. Va
rious causes were ascribed for its
presence. In 1878, however, Prof. Bur-
rill, of Illinois, discovered the true
cause to be bacterial disease due to
the presence of myriads of little germs
in the inner bark and cambium. The
germ was called by Prof. Burrill Nj
crococcuS dmyloUoruS from the eager
ness with which it seizes upon and de-
YOURS the starch in the tissues. From
the subsequent studies of Arthur at the
Geneva Station in New York and of
Waite in the U. S. Department of Agri-
culture we know how this germ or
bacterium lives, reproduces itself and
is carried from tree to tree.
Luckily the disease is very conspic-
uous one which renders it's presence in
an orchard the more inexcusable when
we'll known. 1t affects twigs, leaves,
young fruit, and even the branches or
trunks From the experiments of
Waite, it has been found that it can
not attack the plant through the unin-
jured bark or leaf 1t can, however,
gain entrance through any injured
place on the trunk, limb or leaf. It's
most common points of entrance are
natural ones. These are the young
growing tips of the branch, the stigma
of the flower, or the glands which Sc
crete nectar. Therefore the flower
blight" the "twig-blight," and the
branch or trunk blight" are all forms
of this disease.
In the first. the young twig, espec-
tally if it be growing rapidly, turns
black in both leaf and stem, and when
ever the leaves are blighted, they re-
main black and dead through the en-
suing winter. This black, piratical
flag is the surest evidence of it's pres
ence.
In the "f1ower-b blight" whole bunch
of flowers, or frequently every bunch
upon the tree will be affected, and dy-
ing back to the beginning of the spur,
hold the blackened flowers and young
fruit also through the entire year.
This is the most common form on the
apple.
Frequently an entire limb or even
the trunk will be affected for only
a short distance, while the top will
still be entirely free from the disease,
and this can only be understood when
we speak of how the disease is spread.
Most frequently upon the pear sew
eral limbs and even the whole trunk
will be affected, and when this is the
case the tree should be cut out root
and branch.
If the young shoots of tree affected
with blight be examined, small drops
of sticky, thick fluid will be found ex-
uding from the edge of the diseased
area. If one of these drops be examin-
ed with microscope, myriads of little
oblong bodies will be seen, some sepa-
rate, some in short chains. These are
bacteria. Arthur proved that these
bodies, inOculated into a sound tree by
needle, would produce disease; Waite
proved to us beyond dispute that in
sects, especially bees, are the main in
struments in their dissemination.
They are attracted by the viscid sap,
suck up part or all of the drop, and
then carry these germs with them to
innoculate flowers, shoots, or wounded
places in the bark. Undoubtedly
heavy currents of wind assist in
spreading the disease and probably
account for the commonness of "twig
h1i oht - Tho n11pctiOp oorooc ri oh