110 The Spraying of Plants. 



H. Johnson's mixture : * 



Copper sulphate 8 ounces. 



Ammonium carbonate 1 pound. 



Water 25 gallons. 



I. Copper carbonate 8 ounces. 



Ammonium carbonate 1 pound. 



Water 25 gallons. 



A. Copper carbonate 3 ounces. 



Ammonia 26 1 quart. 



Water 25 gallons. 



B. Copper carbonate 3 ounces. 



Ammonium carbonate 1 pound. 



Hot water 2 quarts. 



Water to dilute to 25 gallons. 



D. Copper sulphate pounds. 



Quicklime 4 " 



Water 25 gallons. 



E. Copper sulphate 1 pound. 



Sal-soda 1\ pounds. 



Ammonia : 1 pint. 



Water 25 gallons. 



After two years' trial of the above, the formulas D, E, and I 

 were shown to be the most effective. D, or the Bordeaux mix- 

 ture, exerted no injurious action on the foliage nor on the 

 fruit ; E, or the modified eau celeste, had but slight action on 

 the foliage ; while preparation I had little or no action on foli- 

 age or fruit. This really implies that the Bordeaux mixture 

 was as effective as any fungicide used, and that it proved to be 

 the safest as well. The only objection raised to it was the 

 difficulty of making the applications. The other preparations 

 were either of less fungicidal value, or they injured foliage. 



Since 1892 exhaustive experiments have been conducted by 

 the United States Department of Agriculture for the prevention 

 of rusts affecting wheat and other cereals. In that year, eleven 

 preparations were applied, two being in the form of powder; 

 the remainder were liquid, and were sprayed upon the plants or 



1 This fungicide was so called from the fact that "Dr. 8. W. Johnson first pro- 

 posed its use in the Ann. Kept, of the Conn. Agric. Exp. Sta. 1S90, 113. It never 

 came into general tise. 



