April, 1912.] SOME APPLE DISEASES TREATMENT. 31 



and should be diluted at the rate of 1 gallon to 30 or 35 for 

 summer use. Some have reported satisfactory results with a 

 dilution of 1 to 100, but the writer's observations do not lead 

 him to believe bhat this strength will hold the diseases in check 

 when they are at all serious. 



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. Solutions having a specific gravity 

 of 1.015 (2.14 Baume) have been repeatedly used in New Hamp- 

 shire orchards without injury to the foliage or fruit, but 1.010 

 (1.44 Baume) solutions have controlled the apple scab and other 

 diseases almost as well as the stronger mixture. When the 

 specific gravity of the stock solution is found the number of dilu- 

 tions is readily determined by dividing the decimal of the con- 

 centrate b}^ the decimal of the spray desired. If the concentrated 

 solution should have a specific gravity of 1.24 (28.06 Baume), 

 the number of dilutions may be determined by dividing .24 by 

 .010, giving 24. To obtain a solution having a specific gravity 

 of 1.010 the stock solution must therefore be diluted to 24 times 

 its own volume. Likewise a stock solution having a specific 

 gravity of 1.30 (33.46 Baume) must be diluted to 30 times its own 

 volume to obtain a solution having a specific gravity of 1.010. 



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. An}' lime residue left as a sediment 

 in the stock solution favors crystallization. 



As an insecticide with lime-sulfur arsenate of lead should be 

 used. 



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

 mended bj' 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 

 small quantities, as under such circumstances the loss of heat is 

 too great. It may be prepared as follows: 



Place 20 pounds of good stone lime in a barrel and pour 3 or 



iCan be obtained from George D. Feidt & Co., Philadelphia, or Eimer & 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 1. 1908. 



