U. S. EXPERIMENT STATION BULLETINS. 425 



This is one of the oldest fungicides, having been used first in 1887. It 

 rarely injures the foliage, and for this reason is much more desirable than 

 the simple eau celeste. The ammoniacal solution has, however, about 

 superseded these preparations in the treatment of nearly all plant diseases. 



Convenient measures. — It is often inconvenient to take scales into the 

 field; moreover, when they are at hand it requires considerable time to 

 weigh out the various chemicals used. If the following facts are remem- 

 bered it will frequently save time and trouble: 



Quarts. 



6 pounds of copper sulphate, crystals 2J4 



6 pounds of copper sulphate, powdered 2 



4 pounds of lime, unslaked, in pieces the size of pigeons' eggs 1% 



4 pounds of lime, slaked 3 



A convenient measure for the copper carbonate may be made from a 

 baking powder can or something similar. First weigh the can, then put 

 in 5 ounces of the chemical and mark the place. We have 1-ounce, 

 2-ounce and 5-ounce cans made in this way, and find them exceedingly 

 useful and labor-saving. 



Manufacturing copper carbonate. — In this connection, and before pro- 

 ceeding with the directions for treatment, it may be well to call attention 

 to the fact that if desirable the copper carbonate can be manufactured at 

 home at about one third the price usually charged for it in the wholesale 

 markets. Following are directions for manufacturing it: 



In a tub or barrel dissolve 6 pounds of copper sulphate in hot water. In 

 another suitable vessel dissolve 7 pounds of sal soda in hot water. When 

 the two solutions are cool, pour the second slowly into the first; then add 

 water until the tub or half barrel is full. Stir the solution thoroughly and 

 let it stand for 24 hours, then siphon off the clear liquid and add fresh water. 

 Stir again, and again allow the solution to stand 24 hours; siphon off the 

 clear liquid as before, then remove and dry the sediment, which is carbon- 

 ate of copper. Using the above quantities of copper sulphate and sal soda 

 there will be formed 3 pounds of copper carbonate. Sal soda sells at 

 wholesale for If cents per pound, so that on this basis the necessary chem- 

 icals to make three pounds of copper carbonate will cost 46f cents, or 15f 

 cents for one pound. The usual wholesale price for this chemical is 40 

 cents per pound. 



TREATMENTS. 



Downy mildew, brown and gray rot. — Use either the ammoniacal copper 

 carbonate solution, eau celeste, or the Bordeaux mixture, preferably the 

 first on account of its being cheaper and not so likely to injure the foliage. 

 Make the first application about the time the berries are well formed, 

 which, as a rule, is 10 or 12 days in advance of the mildew. Kepeat the 

 sprayings every 12 or 15 days, or more often if there are frequent heavy 

 rains, until the berries begin to color. In some sections where the mildew 

 is unusually severe it may prove advantageous to make one or two spray- 

 ings after the fruit is harvested in order to insure perfect ripening of the 

 wood. 



Eau celeste is now largely used in the treatment of this disease in 

 northern Ohio, especially on the islands of lake Erie. In this climate it 

 does not seem to injure the foliage at all, but this can not be said of any 

 other section so far as we know. 

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