6 CIRCULAR 2 3 7, U. S. DEPARTMENT OF AGRICULTURE 



added. The proportions of the materials in this mixture are as 

 follows : 



Pounds 



Finely ground sulphur 8 



Hydrated lime 4 



Calcium casemate % 



All dry materials should be mixed in pails or buckets before being 

 placed in the spray tank. Whenever flour is used, all the dry mate- 

 rials should be thoroughly mixed before any water is added; other- 

 wise the flour will lump badly and cause difficulty during the spray 

 operation. A small quantity of water should be added first and the 

 mixture again stirred, after which sufficient water is added to make a 

 thin paste. It can then be strained into the spray tank. 



SPRAYING EQUIPMENT 



i 



For plants growing under commercial conditions the ordinary 

 high-pressure power outfits in general use for control of other insects 



Figure 5. — Spraying shade trees with high-power outfit. It is essential that the 

 tops of certain varieties of trees he covered with a coating of spray to prevent 

 injury by the beetle 



and diseases can be employed. (Fig. 5.) These outfits are made 

 with pumps of from two to four cylinders having a capacity of from 

 10 to 50 gallons per minute and operated by gasoline engines of from 

 4 to 15 horsepower. Often the pumps are operated by a direct 

 hook-up with the tractor or truck drawing the sprayer. Only the 

 best grade of high-pressure hose which is guaranteed against im- 

 perfections in workmanship and materials should be used and the 

 working pressure under which the hose is to be used should be speci- 

 fied. The length will depend on the conditions under which it is to 

 be employed, although 50-foot lengths are handy when considerable 



