74 INSECTICIDES FOR SUCKING INSECTS 



water. Have the water boiling hot. As soon as the soap is all dis- 

 solved, remove the solution from the fire and add 2 gallons of kero- 

 sene. At once agitate the material violently. This is best accom- 

 plished by the use of a bucket pump, turning the nozzle back into the 

 bucket, so that the material is constantly passed through the pump. 

 In a few minutes a smooth, creamy emulsion is formed, without any 

 free oil. This will become thicker as it cools, but if it is properly made, 

 no oil will separate out. This is the stock material, and will keep well, 

 if sealed from air. 



For use on trees or shrubs that are dormant it is customary to dilute 

 the stock emulsion with 5 to 7 parts of water. On trees or plants in 

 leaf dilute with 10 to 15 parts of water, depending on the type of in- 

 sect and the kind of fohage. Soft-bodied insects such as plant lice are 

 easily killed by a dilution containing only 5 or 6 per cent of oil. 



To get exact dilutions use the following table : 

 For 4% strength add 15f gallons of water to 1 gallon of stock solution- 

 For 5% strength add 12^ gallons of water to 1 gallon of stock solution. 

 For 7% strength add 8| gallons of water to 1 gallon of stock solution. 

 For 10% strength add 5f gallons of water to 1 gallon of stock solution. 

 For 12% strength add 4| gallons of water to 1 gallon of stock solution. 

 For 15% strength add 3| gallons of water to 1 gallon of stock solution. 

 For 18% strength add 2f gallons of water to 1 gallon of stock solution. 

 For 20% strength add 2f gallons of water to 1 gallon of stock solution. 

 For 25% strength add If gallons of water to 1 gallon of stock solution. 



Oil sprays are best applied on a sunny day when the wind is blowing, 

 since surplus oil will then evaporate more quickly and there will be less 

 danger of injuring the plant. 



Crude oils are emulsified in the same way as kerosene. For certain 

 insects, as indicated later, this spray is effective and desirable. 



Linseed Oil Emulsion 



Hard soap 1 pound 



Hot water (soft) 1 gallon 



Linseed oil (raw) 2 gallons 



Dilute as directed. 



