448 Diseases of Economic Plants 



To make copper carbonate proceed as follows: Dissoh^e 

 10 pounds of copper sulfate in 10 gallons of water. Also 

 dissolve 12 pounds of carbonate of soda in the same amount of 

 water. Allow these two solutions to cool, then mix them 

 slowly together, stirring in the meantime. Allow the mixture 

 to settle about 12 hours, pour off the liquid, and add water 

 equal in amount to the liquid poured off. Stir thoroughly 

 and allow it to settle as before. Repeat this operation again, 

 then drain off all the liquid possible, and dry the blue powder 

 which remains. This powder is the copper carbonate. 



Burgundy mixture. 



Copper sulfate 2 pounds 



Sodium carbonate (sal soda) 3 pounds 



Water 100 gallons 



Each chemical should be dissolved separately in half 

 the water, then mixed as in making Bordeaux mixture. 

 This mixture may be used, as may ammoniacal copper 

 carbonate, when it is advisable to avoid the spotting of 

 fruit which would result from use of the Bordeaux mixture. 



Copper sulfate solution, 1-17. — A solution consisting 

 merely of copper sulfate and water to kill spores on the 

 bark and supports may be used before the leaves appear. 



Dissolve the copper sulfate as in preparing the Bordeaux 

 mixture, dilute it to the required strength, and spray upon the 

 trees. The addition of a little lime, one half pound to 50 

 gallons of mixture, enables the operator to see exactly what 

 portions of the tree have been sprayed. 



This mixture must not be used after the leaves appear. 



Potassium sulfid solution. 



Potassium sulfid (liver of sulfur) 1 ounce 



Water 2 to 4 gallons 



This solution should be freshly prepared. It is used as a 

 substitute for the Bordeaux mixture, to avoid spotting, in 



