No 6. DEPARTMENT OF AGRICULTURE. 253 



KEROSENE. 



The results obtained with this material have been excellent so far 

 as effectiveness against the scale is concerned. They have been ex- 

 tremely variable in their effect on the trees. 'Some of the New Jer- 

 sey growers are quite satisfied with it and will continue to use it; 

 but the majority prefer the crude petroleum. 



Kerosene may be used either undiluted, in a mechanical mixture 

 with water or in the form of an emulsion with soaj). 



For winter application the emulsion has proved a failure, prac- 

 tically; but as it is a standard mixture, the directions for making it 

 may be here given. 



Kerosene (gallons), 2 



Water (gallon), 1 



Hard soap, shaved fine (pound), ^ 



Dissolve the soap in boiling water, warm the kerosene and pour 

 it into the boiling suds. Churn with a bucket or other force pump for 

 about five minutes, by pumping from and into the bucket through a 

 coarse nozzle. This will result first in a milky white mixture and 

 soon in a thin cream that becomes difficult to pump. It will be 

 pure white when cold and of the consistency of butter at a tem- 

 perature of sixty degrees. 



This emulsion contains sixty-six per cent, of kerosene and may be 

 mixed with water to any extent; if well made it will keep, without 

 separating, for several days. For summer applications this material 

 has a great range of usefulness; but it is not so good against scale in- 

 sects as the whale oil soap and not so satisfactory as the mechanical 

 mixture. Rain water or other soft water should be used in making 

 the emulsion; if only hard water is available, it should be softened 

 with soda or borax. 



A mechanical mixture of kerosene and water is made by pumping 

 with the same stroke from a kerosene and a water tank in such pro- 

 portions as is desired. The liquids join near the nozzle and are forced 

 out together in a milky, white spray. Anywhere from ten per cent, to 

 fifty per cent, of kerosene to a corresponding percentage of water 

 may be thus applied and a fifteen per cent, mixture is quite effective 

 against scale larvae and recently set scale insects. But nothing less 

 than a fifty per cent, mixture will serve for full grown scales and even 

 this will not always give realiable results. 



Undiluted kerosene has done best for me, in my own practice and 



