The Owosso times. (Owosso, Mich.) 1897-1926, 1908-06-19
Grape Black Rot. /"

| HlIe Iue CllludllC COuulIlOnS nave
much to do with its development,
which is. very rapid during warm,
muggy weather in July and August,
what is called "Black Rot" is really
caused by the growth within the
fruit and foliage of a microscopic
fungus, which develops from spores,
form Of seed, for whose germina-
ton the presence of moisture on the
grapes or leaves is required. A GER
tain degree of heat is also necessary
and the development will be more
rapid if it is seventy degrees or more.
When the conditions are in any
way favorable, there is always danger
of serious, If not entire, loss of the
crop in sections where the disease
has prevailed even to a slight extent,
as it has wonderful reproductive pow
ers. Fortunately, however, the
spores are very delicate and are read
lily destroyed. Among the most eff
fectual remedies are various salts of
copper and in actual practice it has
been found that if the vines are kept
covered with compound of lime and
| copper sulphate commonly known as
Bordeaux mixture, the spores will be
| destroyed and there will be no
| chance of loss from this disease. To
| be effectual, the treatment must be-
gin before the grapes have been at
| tackled, as, once inside, the spread
cannot be checked. For this reason
| also, it is very important that the
trea tment be so thorough as to reach
| every part Of every grape and leaf.
After the vines are in full foliage, it
| is no easy matter to do this; hence,
| care must be taken to avoid a rank
growth of the vines, and the pruning
in the spring should be as thorough
as possible without reducing their
productive capacity. 1t is also nee
| essary to have the vines we'll spread
out on the trellises and if the leaves
become so thick as to make thorough
spraying difficult or impossible. some
OF the leaves or surplus shoots can be
removed, or the latter can be tied
back so that the spray can reach the
grapes. Care should also be taken
when pruning that all rotten grapes
be removed.
Number and Dates of Application.
Owing to the variations in seasons
and the extent to which this disease
prevails, no definite rule regarding
the dates when grapes should be
sprayed can be given If the spray
is washed off by rains, it should be
replaced at once and if the condi-
tons during the latter part of July
and early August favor the develop
ment of the disease, it will often pay
10 give two or three more sprayings
than when it is dry and there is little
rot.
The first application should be
made just before the buds open and
should not only thoroughly soak the
vines but the trellises should also
be sprayed. For this treatment it
will be we'll to use copper sulphate
solution Of two pounds in fifty gal
Ions of water.
After the growth has started and |
before the blossoms have opened the |
first spraying of Bordeaux mixture |
should be made. This should be re-
peated when the fruit has set and is |
the size of small peas. Especially if |
the season is favorable to the devel-
opment of the disease, the sprayings |
should be repeated every ten days |
until the fruit begins to show color.
In case the disease is not very
troublesome upon unsprayed vine
yards, a somewhat longer interval |
would answer, but four or five APP
plications after the fruit has set can
generally be made with profit in
sections where the disease is work
ing.
For the first application of Bor-
deaux mixture it will be we'll to use
four pounds of copper sulphate and
six pounds Of lime in fifty gallons of
water, but for later sprayings the
can be reduced to three and
five pounds respectively. If neces-
sary to spray after the fruit has be-
gun to color, the amounts should be
reduced to two pounds copper sui
phate and two of lime in fifty gallons
Another remedy that can be used
to advantage when the grapes are
is known as "Soda Bor-
deauX." 1t is prepared by dissolving
three pounds of copper sulphate and
one pound of concentrated I've and
shaking five ounces of lime, using
two gallons of hot water for each.
Mix the lime and copper sulphate So
luton and after adding the I've solu-
ion, dilute to fifty gallons.
While an ordinary barrel pump
IAN be used for spraying small vine
Yards by arranging three or four
lozzles on each side, it will be more
if much spraying is to
De done. to ave a special vineyard
outfit. of which there are
'arious kinds on the market.
With suitable equipment it is
possible to spray an acre of grapes
or from eighty cents to one dollar
Ter application, or at total cost for c
abor and material Of four to seven |
Iollars, according to teh number Of I
pplications, for the season. s