26 The European Elm Scale 



OTHER INSECTICIDES 



KEEOSENE EMULSION 



Formula — One bar, one-half pound, Commercial Soap Company's 

 Pale Savon, a common yellow washing soap, cut in thin slices and dis- 

 solved in two quarts of boiling water. 



One gallon Warden & Oxnard's Elaine Oil, Kerosene of good 

 grade, poured into the boiling soap solution after its removal from the 

 fire, the whole mixed and emulsified by pumping through the force 

 pump for ten minutes or until no free oil separates on standing. 



The emulsion made after the above formula seemed perfect, it 

 mixed readily with water in all proportions without the separation of 

 anj^ free oil. 



Reductions — (a). Three parts of the original emulsion with sev- 

 enteen parts of water. 10 per cent Kerosene. 



(b). Three parts of the original emulsion with thirteen parts of 

 water. 12 1-2 per cent Kerosene. 



(e). Three parts of the original emulsion with nine parts of 

 water. 16 2-3 per cent Kerosene. 



SPRAYING EXPERIMENTS 



January 31st, 1908, Reno, Nevada. 



lot I 



(With Atomizer in Laboratory) 



Material — Hibernating larvae in cracks on the smooth bark of a 

 small branch of American Elm. The limb was dead, but the larvae 

 appeared normal in every way. The cracks were all moderately filled 

 with larvae and were of about the same depth and general character 

 throughout the limb. In some, larvae were numerous enough to be- 

 come crowded. Very few dead females or their semi-cocoons were 

 present. 



Application— Kerosene emulsion of different strengths applied 

 as a fine mist by means of an atomizer. The cracks in every instance 

 were filled to overflowing with the solution, which dripped from the 

 bark and stood in the cracks like milk. The branch was in its normal 

 position with the larvae on the underside. The application repre- 

 sented a thorough spraying in every instance. 



Conditions— Room temperature, 60 degrees. Temperature of solu- 

 tion, 100 degrees. After spraying the branch was kept indoors in a 

 warm room for nearly a week in order that the larvae which had been 

 killed by the emulsion might dry rapidly and so be ready for counting 



