282 CULTURE OF IRISH POTATOES 



5-5-50, meaning in the latter case, that it is made with 5 pounds 

 of copper sulfate, 5 pounds quicklime and 50 gallons of water. 

 Bordeaux is made as follows : 



Stock solutions are first prepared. Slack quicklime by slowly 

 adding water until in a fine powder, then make up into a thin paste. 



Copper sulfate solution is made by suspending in a coarse sack in 

 the top of water, as the solution is heavier than water and it will not 

 dissolve in the bottom of a vessel. 



One gallon of water will dissolve three pounds of copper sulfate. 

 This is called a concentrated stock solution. A barrel of each stock 

 solution can be made at one time, as it will keep a long while. 



FIG. 112. Potato affected with the rot, resulting from late blight. 



Mixing Bordeaux. To mix, place two barrels on a platform 

 somewhat higher than the spraying mixture. To make a 3-3-50 

 solution, take one gallon of copper sulfate solution and mix with 25 

 gallons of water in one barrel ; in the other barrel mix enough lime 

 paste to equal 3 pounds with 25 gallons of water; then allow both 

 solutions to run at one time into the sprayer tank. The strength of 

 spray used varies from 3-3-50 to 5-5-50, using the stronger mixture 

 when the disease is giving trouble or there is trouble from rains 

 washing off the mixture. 



Testing the Mixture. When the mixture is made, take out a 



