196 



MANUAL OF GARDENING 



Fungicide spraying formulas. 



The standard fungicide is bordeaux mixture, made in several 

 forms. The second most important fungicide for the home gar- 

 dener is ammoniacal copper carbonate. Sulfur dust (flowers of 

 sulfur) and hver of sulfur (potassium sulfide) are also useful in 

 dry or wet sprays for surface mildews. The hme-sulfur wash, 

 primarily an insecticide, also has fungicidal property (p. 195). 



Bordeaux mixture. — Copper sulfate, 4 lb. ; stone lime or quick- 

 lime (unslaked), 4 lb. ; water, 50 gal. This formula is the strength 

 usually recommended. Stock mixtures of copper sulfate and lime are 

 desirable. They are prepared in the following way : — 



(1) Dissolve the required amount of copper sulfate in water in the 

 proportion of one pound to one gallon several hours before the solution 

 is needed, the copper sulfate crystals being suspended in a sack near 

 the top of the water. A solution of copper sulfate is heavier than 

 water. As soon then, as the crystals begin to dissolve the solution will 

 sink, keeping water in contact with the crystals. In this way, the 

 crystals will dissolve much sooner than if placed in the bottom of the 

 barrel of water. In case large quantities of stock solution are needed, 

 two pounds of copper sulfate may be dissolved in one gallon of water. 



(2) Slake the required amount of lime in a tub or trough. Add the 

 water slowly at first, so that the lime crumbles into a fine powder. If 

 small quantities of lime are used, hot water is preferred. When com- 

 pletely slaked, or entirely powdered, add more water. When the hme 

 has slaked sufficiently, add water to bring it to a thick milk, or to a 

 certain number of gallons. The amount required for each tank of 

 spray mixture can be secured approximately from this stock mixture, 

 which should not be allowed to dry out. 



(3) Use five gallons of stock solution of copper sulfate for every 

 fifty gallons of bordeaux required. Pour this into the tank. Add 

 water until the tank is about two-thirds full. From the stock lime 

 mixture take the required amount. Knowing the number of pounds 

 of lime in the stock mixture and the volume of that mixture, one can 

 take out approximately the number of pounds required. Dilute this 

 a little by adding water, and strain into the tank. Stir the mixture, 



