490 FRUIT INSECTS 



conveniently prepared by using a stock solution of copper sul- 

 fate and milk of lime, storing them in tubs on an elevated plat- 

 form from which the desired quantity of each can be easily 

 drawn off into the spray tank. 



Dissolve the required quantity of copper sulfate in water in 

 the proportion of one pound to one gallon, several hours before 

 the solution is needed ; suspend the copper sulfate crystals 

 in a sack near the top of the water. A solution of copper sulfate 

 is heavier than water. As soon, then, as the crystals begin to 

 dissolve, the solution will sink, bringing water again in contact 

 with the crystals. In this way, the crystals wdll dissolve much 

 sooner than if placed in the bottom of the barrel of water. In 

 case large quantities of stock solution are needed, two pounds 

 of copper sulfate may be (Ussolved in one gallon of water. 



Slake the required quantity of lime in a tub or trough. Add 

 the water slowly at first, so that the Hme crumbles into a fine 

 powder. If small quantities of Hme are used, hot water is pre- 

 ferred. When completely slaked or entirely powdered, add more 

 water. When the Hme has slaked sufficiently, add water to 

 bring it to a thick milk or to a certain number of gallons. The 

 amount required for each tank of spray mixture can be secured 

 approximately from this stock mixture, which should not be 

 allowed to dry out. Hydrated or prepared lime of good quahty 

 may be substituted for the stone Hme. Place the required quan- 

 tity in the barrel or tank and add water. No slaking is required. 

 Do not use air-slaked lime. 



Take five gallons of stock solution of copper sulfate for every 

 fifty gallons of Bordeaux required. Pour this into the tank. 

 Add water until the tank is about two thirds full. From the 

 stock hme mixture add the required quantity. Stir the mixture, 

 add water to make 50 gallons. Experiment Stations often rec- 

 ommend the diluting of both the copper sulfate solution and the 

 hme mixture to one half the required amount before putting 

 together. This is not necessary, and is often impracticable 



