Methods of Control 403 



copper sulphate, four pounds unslaked lime, and fifty 

 gallons of water. With greenhouse crops it is not 

 always necessary to prepare stock solutions. Only 

 enough for immediate use is prepared at one time. 



In preparing Bordeaux the following points 

 should be kept in mind : 



( 1 ) Copper sulphate solutions must be kept only 

 in vessels of wood, fiber, brass, bronze, or copper. 

 They must not be kept in iron or tin vessels, as they 

 corrode them. 



(2) It is necessary to use fresh lime, as air- 

 slaked lime is useless. 



(3) Bordeaux mixture can be used only when 

 freshly mixed. If allowed to stand twelve hours 

 after making, it loses all fungicidal value. 



(4) Bordeaux mixture or lime should never be 

 strained through burlap. The lint of the burlap 

 is likely to work up into the nozzles and clog them. 



(5) Undiluted solutions of copper sulphate or 

 lime should never be mixed together. 



(6) Bordeaux mixture should not be prepared 

 with hot water. 



Ammoniacal Copper Carbonate, The objection to 

 the use of Bordeaux is that it stains the leaves and 

 foliage. 



To avoid staining, colorless ammoniacal copper 

 carbonate may take the place of Bordeaux. It is 

 prepared as follows: 



Copper carbonate 5 ounces 



Ammonia (26° Baum€) 3 pints 



^^^^^ 50 gallons 



