The Ottawa free trader. [volume] (Ottawa, Ill.) 1843-1916, 1888-09-22
DISEASES OF THE GRAPE VINE.

How to Treat Downy Mildew and Black
Rot.
Bulletin No. o, from the botanical divi-
sion Of the department Of agriculture.
consists largely Of reports from special
and volunteer agents Of experiments
made over . wide area Of territory. In
1887, with sulphate Of copper In solution,
or when combined with lime and other
substances, as remedy for the downy
mildew and black rot OF the grape vine.
Six different formulas were employed.
The Bordeaux mixture. blue water or eau
celeste. two different solutions Of sui
phste Of copper. sulphatine and David's
powder.
Bordeaux mixture is made by dissolv-
ing In wooden vessel pounds of sui
phste of copper in 10 gallons of hot
water, and in another vessel 10 pounds Of
lime In gallons Of water. and mix when
cold, to form q spray solution. Blue
water or eau celeste, is prepared by dis
solving pound of sulphate Of copper In
4 gallons of hot water. When dissolved
and cold add pint Of liquid commercial
ammonia Dilute to % gallons and pro-
coed as with Bordeaux mixture. The
two simple solutions are respectively l
and pounds of the sulphate to % gal
Ions Of water.
Sulphatine and David's powder are dry
and applied with a bellows. OF the ex-
pei iments that have been made, the chief
of the section of vegetable pathology says
the results can in no way be deemed con-
elusive, as diverse results have been OBJ
tanned by parties who have apparently
pursued the same line of experiments;
but what has been accomplished is de-
cidedly encouraging, and we may reason
ably hope for better and more decisive
results the coming season.
Lengthy reports were received from
special agents at Charlottesville, Va;
Vineland, N. j.. Denison, Tex, and
Neosho, Mo-, together with the volunteer
reports from great many persons in
other grape growing states. At Char
lottesville it is stated that vines that
were left untreated clearly showed the
absence of any influence that might tend
to check the ravages of mildew in those
varieties that are known to be subject to
it. In respect to black rot a small advan-
tage accrued to the treated vines. From
Vineland the statement is made that 1t
was the wettest season ever known In
southern New Jersey, and the conclusions
drawn from the experiments that were
made are that the copper sulphate may
ordinarily be relied on on as a preventive
of grape mildew, and the Bordeaux mix
ture is thought to be the preferable one.
Grapes treated for black rot, rotted
equally with those not SO treated. Deni-
son, Tex, reports that there seems to be
positive evidence of preventive effects in
the use of the different preparations of
sulphate of copper, especially in early APP
plications with the Bordeaux mixture,
when it reaches every part of the surface
of the fruit. The most certain escape
from black rot consists in planting varie-
ties that are known to resist it, such as
Perkins, Ives, Delaware, Norton. etc.
From the hundreds of reports from
these and other states it is made to ap.
pear that generally the sulphate of copper
is beneficial for mldew, though not inva
riably so, and the Bordeaux mixture and
eau celeste the best formulas for its use.
For black rot none were satisfactory, and
while the remedies that have been named
are the best we know Of at present for
diseases of the grape, further experiments
will be necessary to test their full value.