The Hood River glacier. (Hood River, Or.) 1889-1933, 1904-06-02

I
something Of absolute knowledge
offer about II. Various causes WEI
ascribed for its presence, such =. 80,
sap, ;" " atmospheric cond t.ons," $50
conditions" and "efiecis tf variot
fungi" In 1897, howevtr, Professf
Burrill Of Illinois discovered tie tru
cause and announced his discovery
the world. This was found to be bacte
ial disease, due to the presence
myriads of little germs In the lnne
bark aud cambrium. The germ wa
called by Professor Burrill MicrOccu
anylov0rus from the eagerness wit
which it seizes upon and devours tn
starch in these tissues. From the sui
sequent studies of Arthur at the Gene
va Station IN New York, and Of Wait
in the u. s. Department of agrlcultur
we know how this germ or bacterlun
lives, produces itself and Is carries
from tree to tree.
Luckily the disease Is very con
spiclous one, which renders its pres
ence in an orchard the more inexcus
able when well known. 1t affect
twigs, leaves, young fruit, and even
the branches or trunks. From the ex
periments of Waite, IL has been fOunt
that it cannot attack the plant through
the uninjUred bark or leafIt tan, how
ever gain entrance through any injured
place on trunk, limb, or even leaf. lti
more 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 "fiower
blight" the "twig.blight" and the
"branch or trunk blight" are all forms
of this disease.
In the first, the young twig, espe.
cially If it be growing rapidly, turns
back in both leaf and stem, and where.
ever the leaves are bllghted they
remain black and dead through the en-.
suing winter This black, piratical
flag il the surest evidence of its pres
ence.
In the "hower-blight" u whole
lunch of flowers, or frequently every
bunch upon the trees will he affected
and dying back to the beginning oI
the spur, hold the blackened flowers
aud young fruit also the entire year
This Is the most form on the apple
Frequently an entire limb or even
the trunk will be affected for only d
short distance, while the top will still
be entirely free from the disease, and
and this can only be understood wher
we speek Of how the disease IL spread
More frequently upon the pear sew
ernl limbs and even the whole trunk
will be affected, aud when this is thu
case the tree should be cut out root anC
aud branch.
If the young shoots of u tree affected
with blight I've examined, small drops
of sticky, thick fluid will be found ex
ud,ng from the edge Of the disease area
If one Of these drops I've examined witt
high power Of u microscope, myriadi
of little oblong bodies will be seen
some separate, some In short chains
These are bacteria. Arthur proved
that these bodies inoculated Into I
sound tree by needle, would produc'
the disease. Waite proved to usb eyont
dispute that insects, especially bees
are the main instruments In their dis
scmination. They are attracted by tn,
viscid sap, suck up part or all OF thu
DRIP, aud then carry thousands o
these germs with them to inoculat,
hOpuis, shoots, or wounded places II
the bark. Undoubtedly heavy current
u Wind assist in spreading the diseas
aud probably account for the common
ness Of "twig-blight." The question
comes right here: Shall | keep bees
! have ali orchard? Certainly, and 70
two reasons. First, the honey, and th
revenue derived from 1t, are often II
small object TO the farmer. Second
the bees are absolutely needed to assis
In proper cross-ftrtilization or pollina
ton of the flowers. This leads us t
the subject of remedies, for preventive
there are none.
AS soon as the bacteria are carried L
young flower or wound, they efiec
entrance, and living upon the sap an,
starch, multiply rapidly. II they gal,
entrance along II limb or trunk, the,
live in the inner bark aud cambrium
layer-that layer which adds yearly Il
the growth of both barb aud wood.
1t can readily be seen from this tina
they are well covered and consequently
spraying does nc good, The only rem
edy thus far found has been and Is tn,
careful and continuous use of the saw
and pruning knife. All diseased
shoots aud limbs should be cut off q
from six inches TO one foot below th,
place Of evident infection or injury, AZ
the bacteria have always gone dowl
deeper into the limb than seems to b,
the case from the out side. Manl
pruners have the habit of splitting
down the pear or apple orchard, thu
knife how far the disease has proceed
ed, or saw should be steriized eact
time II IL used, by either passing II
through, or dipping it into weak ear
bolic acld-water,or into kerosene. The
pruned limbs or fragments should bt
collected and burned and both puninp
and burning should be done mainly In
the dormant season, before the sap has
started, the bacteria have awakened
aud the bees are visiting the orchard
This Is the best time for pruning anC
burning, but not the only one; il
should be done whenever the diseas,
makes its appearance. All large
wounds should be painted over with
paint as soon as the tree Is trimmed, tC
prevent the re-inoculation, through the
exposed tissues. Where the blight /.
bad, even young shoots or water
sprouts should have their cut bases
painted, for 1t has been shown time and
again that the limbs aud even trunks
have been inoculated through these
cut stubs,