206 LABORATORY MANUAL OF AGRICULTURE 



Three pounds of copper sulphate. 



Four pounds of fresh lime. 



Fifty gallons of water. 



The proportion of lime is sometimes increased if there is 

 danger of spray burn. The lime is slacked by pouring water 

 over it, and the copper sulphate is dissolved in water. Both 

 the copper sulphate solution and the lime solution should be 

 diluted to twenty-five gallons and then poured together. 

 The entire solution should be poured through a strainer to 

 remove coarse material. 



Lime sulphur can be purchased on the market as such. 

 Commercial brands usually test 32 or 33 Baume". Material 

 of this strength should be diluted about thirty to thirty- 

 five times with water before using on trees that are in 

 leaf. 



Lead arsenate spray may be prepared* by dissolving two to 

 four pounds of lead arsenate in fifty gallons of spray material. 

 Lead arsenate may be used in the same spray with Bordeaux 

 mixture or lime sulphur. Spray burn sometimes results 

 from the use of Bordeaux mixture in wet weather, and from 

 the use of lime sulphur in dry weather. When both 

 sprays are used together, one application will be effective 

 in combating both the codling moth and fungous diseases. 

 Spraying must be done at various periods to protect the 

 apple crop successfully. 



Equipment. 1. Thirty grams of copper sulphate. 



2. Fifty grams of fresh lime. 



3. Two two-gallon crocks. 



4. One four-gallon crock. 



5. Ten grams of potassium ferrocyanide. 



