28 
APPLE SCAE. 
portion, or plant body, of this as well as of many other fungi, is 
very resistant to the action of chemical reagents quite as much 
or more so than are the tissues of the leaf or apple upon 
which it grows. We can scarcely hope, therefore, to accomplish 
its destruction, unless it be the growths infesting the young 
shoots and the scales of buds. Before the latter expand in 
the spring much stronger solutions can be applied than it is 
possible to use later in the season, and it is at this period 
that the warfare against this fungus should begin. It has been 
observed that the germination of the spores is wholly prevented 
in very dilute solutions of copper, and our chief dependence 
in combating this disease appears to rest upon this fact, the 
possibility of preventing the germination of the spores where they 
can do harm. A practical treatment has been discovered by which 
we may prevent the germination of the spores of the downy mildew 
of the grape vine, by applying various solutions of sulphate of 
copper to the surface of the leaves upon which the spores of the 
fungus fall. It is doubtless equally practical to accomplish by a 
similar treatment a like result in the case of the Fusicladium of 
the apple. Experiments already made with the sulphate of copper 
solutions indicate that they will, when properly applied, at once 
check the ‘ scab.’ Further and more systematically conducted 
experiments are required in order to determine fully what prepara- 
tion is most efficacious, at what season it is best to make the 
application, and the strength to which the solutions must be 
limited. Where eau celeste, prepared according to the original 
formula, has been tried it has severely burned and injured the 
foliage. This preparation may be rendered less caustic by the 
addition of ordinary carbonate of soda.” 
“ Another and more simple modification of the eau celeste is 
prepared by dissolving in one quart of liquid ammonia, four to six 
ounces of carbonate of copper, then dilute with water to 25 gallons. 
The ammonia and carbonate of copper solution may be kept in a 
bottle and diluted when required for use at the rate of about one 
ounce of the solution to the gallon of water. Those who have 
used this preparation on the grape vine say it is perfectly harmless 
to the foliage, and is as efficient against mildew as eau celeste. 
“ Simple solutions of sulphate of copper should not be employed 
during the growing season, as their use is almost certain to result 
in injury to the foliage. The Bordeaux mixture may be used at 
any time without fear of injury. In using one or the other of these 
preparations the following course of treatment is suggested : — 
“ (1) In early spring, before the buds have commenced to 
expand, spray the trees thoroughly with a solution of sulphate of 
iron, using four pounds of the iron sulphate to four gallons of water. 
“ (2) As soon as the fruit has set, apply the Bordeaux mixture, 
or one of the modified preparations of eau celeste. 
“ (3) If the weather should be such as to favour the development 
of the ‘ scab ’ fungus, a third application should be made two or 
three weeks after the second, using the same materials. 
