42 BULLETIN 891, U. S. DEPARTMENT OF AGRICULTURE. 



PREPARATION OF KEROSENE EMULSION. 



There are several forms of kerosene emulsion, but that used with 

 fish-oil or soft soap has been found by years of experience to be 

 the best. 



Kerosene-soap emulsion is prepared by combining 2 gallons of 

 kerosene, 2 pounds of fish-oil or other soap, or 1 quart of soft soap, 

 with 1 gallon of water. Laundry soap, if dry, is shaved and dis- 

 solved in boiling water and then poured (away from the fire) while 

 still boiling hot into the kerosene. The mixture is then churned 

 rapidly for from 5 to 10 minutes, pumping the liquid back upon 

 itself by means of a force pump and direct-discharge nozzle throw- 

 ing a strong stream. At the end of this time the mixture will have 

 become of the consistency of thick cream. Properly prepared, an 

 emulsion will keep throughout a season and should be diluted only 

 as needed for use. For most species of insects the staple emulsion 

 should be diluted with from 10 to 20 parts of water. For this species 

 a 10 per cent dilution has been found effective. In the preparation 

 of kerosene emulsion a force pump is a necessity, since if not made 

 according to directions a perfect emulsion is not formed. There is 

 then danger of injury to the plants by the kerosene, as also useless 

 waste of material. 



After the emulsion has been applied it should be followed by a 

 copious application of water from a hose in order that the insecticide 

 may penetrate more deeply into the soil. In the preparation of 

 kerosene emulsion other soaps than those mentioned may be used. 



Where unskilled labor is employed, the operators should be care- 

 fully instructed as to the difficulties and intricacies involved in apply- 

 ing the emulsion that it may not be brought into direct contact with 

 the plants, which might thus be seriously injured. Where laborers 

 of the better class are not available, fish-oil soap and other soap solu- 

 tions containing no kerosene are preferable. 



Trapping Methods for the Grubs. 



Three methods for trapping the green June beetle larvae were used 

 experimentally during the fall of 1914 on the farms of Messrs. Fred 

 and George Richardson, at Portsmouth, Va. : 



(1) By placing boards on the surface of the ground; (2) by set- 

 ting flowerpots in the ground; and (3) by constructing V-shaped 

 troughs in infested fields. 



THE BOARD METHOD. 



Boards 12 feet long and 16 inches wide were placed closely to- 

 gether on the surface of the ground in a field infested with grubs 



