Democratic Northwest. [volume] (Napoleon, Ohio) 1869-1894, 1891-02-12
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RESULTS OF SCIENTIFIC AGRI-
CULTURAL EXPERIMENTS. =.
The Brown Rot In Grapes, the Histo-
~ and Nature OF the Disease and
How it May be Prevented.

~ and Nature OF the Disease and
How it May be Prevented.
In bulletin soon to be issued by the
Ohio Experiment Station, DIR. G. NJ.
Weed gives the following account Of
the Downy Mildew or Brown Rot of
grapes:
For many years the vineyardists of
the great fruit belt in northern Ohio
along the southern shore of Lake Erie,
have been troubled by disease affect
| ing the foliage and fruit of the grape
called Downy Mildew or Brown Rot.
At times this disease has ruined nearly
the entire crop, and has threatened to
destroy the vineyard industry over a
large area. Fortunately, however, this
disaster has been averted by the discov-
cry of method by which the disease
can be largely or entirely prevented at
comparatively slight expense.
THE CAUSE OF THE DISEASE.
The downy mildew or brown rot of
grapes is q fungous disease-that is, 1t is
diseased condition of the foliage or
fruit due to the presence of a fungus.
This fungus is q minute parasite plant
that developes at the expense of the tis-
sues of the grape, thus causing blight
ing of the leaf and decay ofthe fruit. It
is distributed over nearly the entire
eastern half of the United States, and
occurs upon both the wild and cultivat-
ed varieties Of grapes. 1t probably
lived upon the former before the intro
duction Of the latter. 1t attacks all the
green parts of the vine, including the
young shoots, as well as the leaves and
berries, and like other fungi reproduces
by means of spores, minute bodies cor
responding in function to the seeds of
Towering plants.
When one Of these spores falls upon
q leaf where there is sufficient moist
ure, it terminates by sending out lit
tie tube-something as kernal of corn
in moist soil sends out its terminating
lradicle-and this tube penetrates the
epidermis or skin of the leaf. Once in
side, the tube continues to grow, push
ing about between the cells of the leaf,
and forming what is called the mycel-
ium or vegetative portion of the fun
gus, which may be likened to the roots
of higher plants. As there is little
nourishment to be obtained between
the cells, this mycelium developes
minute processes which push through
the cell walls and absorb the contents.
!, After this mycelium has developed in
the leaf for some time tis ready to pro-
duce its spores. Consequently it sends
out through the breathing pores, or
stomata, Of the leaf its fruiting branch
les. These bear upon their tips small
oval bodies which are the spores. The
| 70
eye is composed of these fruiting
/, branches and their spores. 1t only de-
| velopes under certain atmospheric een-
! ditions, SO that the mycelium may ex-
: list in the affected parts of the vine for
! some time before this outward manifes-
!. tation Of its presence occurs. This is
the reason that vineyard may appar-
, emily be struck" with mildew in sim
9 gle night.
Besides the spores above described,
which are produced during the sum-
mer season, and consequently are call
ed summer spores, there is developed in
fall different class of spores by which
the fungus passes through the winter
: Hence these latter are called winter
. spores.
REMEDIES.
\ A knowledge of the method of devel.
opment of the fungus makes it evident
! that it cannot be reached after it has
! penetrated its host. Consequently rem
g edial treatment must be limited to de-
= stroying the spores, and preventing
9 their ingress to the tissues of the plant
e The experience of the last few years has
] shown that this can be successfully ac
Y complished by spraying the vines with
g dilute solutions of certain sails of cop.
+ per, particularly sulphate of copper OF
Y "blue vitfiol.n
e Experiments with these copper com
s pounds as preventatives of the severa
e fungous diseases of the grape have beer
e in progress in France for a number O
d years and have been attended with re
y markably successful results. The sub
n ject was taken up in America about tht
o middle of the last decade, and wonder
full progress has since been made. W.
are largely indebted to the United
n States Department of Agriculture fol
J. the results obtained, especially tt
i Messrs. Scribner and Galloway, whit
k have had the work in charge. In Ohit
the first experiments were apparently
made by Mr.. George M. High, of Otta
wa county, who for the last five year
has tested the remedies thoroughly ant
= has triumphed over tue unprogressiv'
l. growers who were content to let tb
It disease destroy their crops rather thai
t try any new-fangled methods of check
k ing it.
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o bought a machine for plating golG
o silver and nickel, and it works spler
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