, 1911-02-11
BORDEAUX MIXTURE.

the fact that the mixture OF copper snIphate
and milk of lime for fungicide purposes
originated in the city of Bordeaux in France.
1t was first used i'll the form of q thick paste
on vines near the highways to prevent the
theft of the fruit. When sprinkled on the
vines i'll this way the mixture was very con-
spicuous, and as there was a popular idea
that it was extremely poisonous, it was a
very effective preventive. 1t is not known
when this practice originated, but it was first
brought to the attention Of viticultHrists in
1885, by NJ. MilIardet, Professor Of Botany
at Bordeaux.
In 1882, Millardet visited the vine grow
ing region about Medoc and learned from
She grape growers there that such vines as
they treated with this paste were entirely
free from the downy mi(dew, which was q
serious disease, During the next few years
M. Millardet carried out experiments with
BordeauX mixture, and demonstrated the
great value Of copper ~sulphate and lime rs u
means of control of those t ungoid parasites
of plants which live on the surface, or which
gain admission through the epidermis.
In the past twenty five years, Bordeaux
mixture has come to have n very wide and
varied use. La France for many years it was
principally applied to vines as Il protection
from the diseases pecullar=to grapes, but i'll
other countries it was tried III cOnneXlOn
with the control of all fun3oid plant diseases.
Bordeaux mixture is safe to use, since it
is not a very active poison in its effect on
man, and when properly made it does not
iniure the foliage OF plants. 1t has special
value as a preventive application on plants
liable to fungoid attack, and the fact tImt it
may be used us u carrier for the ordinary
arsenical insecticides gives it even Il greater
w,,,,r, Df ,,aaE,rInoco E'OV iOctoDaa RNrlaonv
mixture to which Paris green, arsenate of
lead, or other poison has been added, may
be sprayed ON trees or other plants, ana this
gives "a protection from the attacks Of both
insects and fungi. The adhesive properties
OF Bordeaux mixture enable the arsenicals TO
remain on leaves OF bark much longer than
when they are sprayed without the mixture.
Preparation OF Bordeaux Mixture.
It has already been stated that Bordeaux
mixture is Il preparation of copper ~sulphNte
ObIuestouo) and lime i'll water. The follow
ing proportions may be used -
Copper sulphate 4 ID, temper lime 4 H..
water 80 gallons.
The copper suIphate is dissolved in 25 gal
Ions Of water in n barrel or wooden tub.
The most convenient method is to put the
copper sulphate in a coarse sack and hang it
from a stick across the top of the casE III
such a way that it is just submerged i'll the
water. The lime is slowly slaked in a wood
Oh tub, and water added to make 25 gallons.
The bluestone solution and the lime wash
are mixed by being poured at the same time
into q third cask capable Of holding the Gu
tire SO gallons of the mixture. Emphasis is
laid on the method of mixing, which may be
accomplished 10y two men, one pouring the
copper sulphate solution and the other the
lime wash, by means OF buckets. Copper
sulphate and Bordeaux mixture should
always be kept in wooden containers as far
as possible, and not in metal, and the slak-
ing of the lime should also be done in wood
en- vessels.
Bordeaux mixture should always be tested
for any excess of uncombined copper salts,
which might be injurious to the plants to be
treated. There are two recognized tests
the knife blade, and the ferrocyanide of po-
fash test. When the copper sulphate soIu-
ton and lime wash have been poured togeth-
err and thoroughly stirred, the mixture may
be tested by means of q clean, polished knife