276 STATE HORTICULTURAL SOCIETY. 



KEROSENE EMULSION. NEW OR RARE INSECTS. 



Bulletin No. 73, Michigan Experiment Station. 



Among the several excellent insecticides few, if any, surpass in value the 

 Kerosene Emulsion. Even the arsenites hardly equal this, as they can 

 only be used effectively against mandibulate insects, while this, as it kills 

 by contact, is not thus limited in its use. It kills sucking insects as well as 

 those which bite and eat the leaves, twigs, etc. I gave last year (see Bul- 

 letin 58, or Report of Michigan Board of Agriculture, 1890, p. 220) my 

 formula for preparing this emulsion, as I have used it for years — first in 

 1877. Last autumn Dr. C. V. Riley honored me with a visit; he told me 

 that my formula would not make an emulsion, that it only produced an 

 unstable mechanical mixture. But I said it does produce a stable mixture 

 with me, capable of easy and perfect dilution. I said I have some now in 

 our museum which has stood for years. He said, let us look at it. I 

 eagerly produced the bottle. He said, that is no emulsion, that has sepa- 

 rated, and is only a mechanical mixture, and was used years before you 

 recommended it, by Mr. Taylor and others. At the very interesting and 

 profitable meeting of Entomologists at Champaign, Dr. Riley recited this 

 occurrence, when Prof. C. P. Gillette remarked that he had found the Hub- 

 bard-Riley formula much better than the one I had used and recommended. 

 The statement by Prof. Gillette seemed to meet general approval. 

 This startled me, as well it might, for I had recommended the Kerosene 

 Emulsion made according to my formula to thousands both through the 

 press and at farmers' institutes. If I had been recommending an inferior 

 article, it was a serious matter. Yet I had this comfort, I had received 

 testimony from a great number and with no complaint. All pronounced it 

 entirely satisfactory. As Prof. L. R. Taft said to me, when I asked him if 

 he had ever compared the two: "I have never used the Riley emulsion, as 

 I find yours entirely satisfactory. I want nothing better." Thus I was 

 startled, I say, to receive such an opinion from one so exceedingly able as 

 Dr. Riley, and from so careful and conscientious an investigator as Prof. 

 Gillette. I remarked at Champaign that my formula had given me and 

 others entire satisfaction. If the Hubbard-Riley formula were better I 

 should be glad to know it and recommend it. 



My formula recommended for years is this : Dissolve in two quarts of 

 water one quart of soft soap or one fourth pound of hard soap, by heating 

 to the boiling point, then add one pint of kerosene oil, and stir violently 

 for from three to five minutes. This is best done by pumping the liquid 

 into itself through a small nozzle, so that it shall be thoroughly agitated. 

 This mixes the oil permanently so that it will never separate, and can be 

 diluted easily, at pleasure, by simply shaking or slightly stirring after 

 adding the water to dilute it. I have often stated that it was not neces- 

 sary to use so much soft soap, but was better, as it insured a perfect emul- 

 sion even upon dilution, and the soap itself is an isecticide, and valuable, 

 aside from its emulsifying power. I also have stated that in using soft 

 soap a quart of water woulcl do. I prefer, however, the two quarts, as the 

 emulsion is more sure, and the thinner material permits more ready and 



