486 FRUIT INSECTS 



be agitated constantly while being applied, as it settles rapidly. 

 When properly made this is simply a fine mechanical mixture of 

 lime and sulfur produced by the heat and bubbling action of 

 slaking, and should have but little sulfur in solution. This 

 mixture is especially adapted for the spraying of peaches and 

 plums in foHage, as it causes no injury. Arsenate of lead may 

 be added to this mixture for the control of plum curculio. 



EMULSIONS 



Emulsions are oily or resinous sprays in which these sub- 

 stances are suspended in water in the form of minute globules, 

 a condition brought about by the addition of soap. They form 

 an important class of contact insecticides useful particularly 

 against scale insects and plant-lice. 



Kerosene Emulsion 



Kerosene emulsion is one of the oldest of our contact in- 

 secticides. It is especially valuable for use against plant-lice 

 and other small, soft-bodied insects. It is prepared by the 

 following formula : 



Soap h pound 



Water 1 gallon 



Kerosene 2 gallons 



Dissolve the soap in hot water ; remove from the fire and while 

 still hot add the kerosene. Pump the liquid back into itself 

 for five or ten minutes or until it becomes a creamy mass. If 

 properly made the oil will not separate on cooling. 



For use on dormant trees, dilute with 5 to 7 parts of water. 

 For killing plant-lice on foliage, dilute with 10 to 15 parts of 

 water. Crude oil emulsion is made in the same way by substi- 

 tuting crude oil in place of kerosene. The strength of oil emui- 



