328 REPORT OF THE COMMISSIONER OF AGRICULTURE, 
IIl.—NovEs UPON THE TREATMENT OF ‘VINE DISEASES. 
The preparations considered most likely to prove valuable as rem-— 
edies in the treatment of mildew and black-rot were published last 
spring (1887) in the following circular form: 
[Section of Vegetable Pathology.—Circular No. 3.] 
Treatment of the downy mildew and black-rot of the grape. 
To the vineyardists of the country? 
Last year a circular was sent out by this Department recommending for trial cer- 
tain remedies for the mildew and rot of the grape. 
The results of experiments in 1886 have fully demonstrated the value of sulphate 
of copper (‘‘ blue-stone”’) over all other remedies in combating the mildew, and the 
results of many chemical analyses of the fruit and parts of vines treated with the 
copper compounds have clearly shown that there is no danger to health attending 
their application. The only precaution advised is not to apply them near (within 
fifteen days of) the vintage. 
In their employment fhe fact must be kept in mind that their action is only pre- 
ventive, therefore their application should be made early in the season, from the 
latter part of May to the end of June. Subsequent applications act only in so far 
as they serve to check the spread of the disease. The amount of the fluid com- 
pounds required to treat an acre of vines will depend largely upon the kind of pump 
and spraying nozzle used to apply them, and upon the extent of growth of the 
vines themselves; the amount may vary from 20 to 35 gallons. 
The following are the formule of the remedies which so far have given the best 
results. An account of the results of trials you may make with one or more of 
them is earnestly desired, and a blank form for making up a report for the use of 
the Department in future publications will be sent you upon the receipt of the ad- 
dressed postal card inclosed herewith. 
LIQUID REMEDIES, 
(1) Simple solution of sulphate of copper.—Dissolve 1 pound of pure sulphate of 
copper in 25 gallons of water. Spray the vines with a convenient force-pump hav- 
ing a nozzle of fine aperture. Less lasting in its effect than the next, as it is easily 
washed off by rains. 
(2) Eau celeste, blue water {the ‘‘Audoynaud process”).—Dissolve 1 pound of sul- 
phate of copper in 8 or 4 gallons of warm water; when completely dissolved and the 
water has cooled, add 1 pint of commercial ammonia; then dilute to 22 gallons. 
The concentrated liquid should be kept in a keg or some wooden vessel and diluted 
when required for use. Apply the same as in the case of simple solutions. 
The effects obtained by this preparation have been equal to those resulting from 
the use of the copper mixture of Gironde, and are said to be even more lasting. 
(3) Copper mixture of Gironde, Bordeaux mixture.— Dissolve 16 pounids of sulphate 
of copper in 22 gallons of water; in another vessel slake 30 pounds of lime in 6 gal- 
lons of water. When the latter mixture has cooled, it is slowly poured into the 
copper solution, care being taken to mix the fluids thoroughly by constant stirring. 
It is well to have this compound prepared some days before it is required for use. 
It should be well stirred before applying. Some have reduced the ingredients to’ 2 
pounds of sulphate of copper and 2 pounds of lime to 22 gallons of water, and have 
obtained good results. 
Well made pumps with specially constructed nozzles are required for the applica- 
tion of this compound, unless we resort to the tedious and wasteful method of using 
brooms or wisps made of slender twigs, which are dipped into the compound and 
then switched right and left so as to spray the foliage, as directed in our circular 
of last season. The Vermorel apparatus, including reservoir, pump, and spraying 
nozzle, is well adapted for vineyard use, and is specially constructed for applying 
the various liquid preparations containing sulphate of copper. 
POWDERS. 
(4) David's powder.—Dissolve 4 pounds of sulphate of copper in the least possible 
amount of hot water. and slake 16 pounds of lime with the smallest quantity of 
water required. When the copper solution and the slaked lime are completely 
cooled, mix them together thoroughly; let the compound @ry in the sun; crush and 
