288 CONTROLLING INSECTS AND DISEASES 



coarse particles. "Put the water between" is an axiom in preparing 

 Bordeaux mixture. A good method is to put the copper sulfate solution 

 in the tank and add water until the tank is about two-thirds full. Start 

 the agitator. Stir the lime mixture thoroughly, and strain the correct 

 amount into the tank, washing it in gently with a hose. Fill the tank 

 with water and spray out at once, keeping the tank well agitated. If 

 the mixture must be kept several hours or longer, add a heaping table- 

 spoonful of ordinary cane sugar dissolved in a little hot water to each 100 

 gallons of spray material. This will cause it to keep in good condition 

 indefinitely. 



Unless sufficient lime is present to neutrahze the copper, burning of 

 fruit or foliage may result. The formula is intended to provide the neces- 

 sary lime content, but nevertheless the grower should test the material. 

 Hold a clean, polished knife blade in the diluted preparation for a 

 moment. If no copper is deposited on the blade, the mixture is safe. 

 The potassium ferrocyanide test may also be used. If a drop in the 

 spray material gives a brown or red reaction, the lime is insufficient. 

 If the reaction is yellow, the lime is sufficient to neutralize the copper. 



Hydrated copper sulfate in powder form may now be 

 obtained and pom^ed directly into the tank, adding the lime 

 as directed. This eliminates making the stock solution of 

 43opper sulfate, and it is claimed that results are equally 

 ;satisfactory. 



Hydrated lime in a very fine state of division may be sub- 

 stituted for the burned lime, but is more expensive at the 

 present time. It requires 66 pounds of hydrated lime to equal 

 ^each 50 pounds of the burned lime in the stock solution. 



For the preparation of Bordeaux mixture in large quantities 

 and for rapid work in the spraying season, an ample water 

 supply is essential. An elevated mixing platform from which 

 the materials pass by gravity is desirable. The spray tank 

 should be equipped with a large copper or bronze strainer 

 with at least 16 meshes to the inch, through which the mate- 

 rials pass into the tank. 



Pipes and hose should be at least 2 inches in diameter to 

 permit the quick performance of all operations. The stock 

 solution tanks should be large enough to hold materials for a 

 full day's spraying. 



