Dec, 1909J SOME APPLE DISEASES. 137 



\ 



Prepared lime-sulfur mixtures can be obtained on the market. 

 A number of companies are selling a good product, and the com- 

 mercial lime-sulfur has much more in its favor both as to quality 

 and price than the patent Bordeaux. It is usually stronger 

 than that obtained by the above method of preparation and 

 must be diluted at the rate of 1 gallon to 25 or 30 for summer 

 use. 



It is very desirable that a hydrometer, or specific gravity 

 bulb be used in making dilutions of lime-sulfur. If an instru- 

 ment^ having a scale reading from 1.000 to 1.35 is obtained, it 

 may be used for testing the strength of both the concentrated 

 and the diluted solutions. When the specific gravity of the stock 

 solution is found the number of dilutions is readily determined 

 by dividing the decimal of the concentrate by the decimal of the 

 spray desired. Solutions having a specific gravity of 1.015 

 have been repeatedly used without injury to the foliage or fruit, 

 but 1.010 solutions have controlled apple scab and other diseases 

 almost as well as the stronger mixture. From our present 

 knowledge of the subject a solution having a specific gravity 

 of 1.012 seems most desirable for summer use in the apple 

 orchard. If the solution as obtained by the use of the above 

 formula should have a specific gravity of 1.24, the number of 

 dilutions may be determined by dividing .24 by .012, giving 

 20. To obtain a solution having a specific gravity of 1.012 the 

 stock solution mu.st therefore be diluted to 20 times its o\\ti 

 volume. Likewise a stock solution having specific gravity of 

 1.30 must be diluted to 25 times its own volume to obtain a solu- 

 tion having a specific gravity of 1.012. 



Stock solutions of lime-sulfur may be prevented from crystal- 

 lizing on the exposed surface by covering them with a thin layer 

 of oil to exclude the air. Any lime residue left as a sediment 

 in the stock solution favors crystallization. 



Self -Boiled Lime-Sulfur. — A self-boiled lime-sulfur recom- 

 mended by Scott- has given good results in New Hampshire 

 orchards. The heat for combining the lime and sulfur is obtained 

 from the slaking lime. The mixture should never be made in 



> Can be obtained from George D. Feidt & Co., Philadelphia, or Elmer and Amend, 

 New York City. 



»Scott, W. -M. Self-Boiled Lime-Sulfur Mixture as a Promising Fungicide. U.S. 

 Dept. Agr. Bur. of Plant Industry. Circular l. 1908. 



