36 FIFTH REPORT OF THE ENTOMOLOGICAL COMMISSION. 



ard strength and has long been used as an insecticide wash. It is made 

 from various fish oils and fish-oil residue with caustic soda. Better 

 success attends the use of jelly soaps made directly from fish-oil and 

 concentrated lye, with water, using about three gallons of water, three 

 pints of fish-oil, and one can of lye. Various preparations of this nature 

 can easily be made. Coarse grease does not make so good a soap as oils. 



The whale-oil soap sold in the stores is used in solutions of one jiound 

 in two to five gallons of water, experiment being necessary to deter- 

 mine what strength will be efficient. The jelly-soap made as mentioned 

 above has been successfully used on Aphides, when fresh, in strength of 

 1 pound to 8 gallons of water. For most work, however, it would need 

 to be stronger. 



Petroleum Products: Kerosene, Naphtha, etc. — Among the washes of an 

 insecticide nature which kill by contact there is probably nothing equal 

 to the preparations from petroleum. Of these it is only necessary to 

 notice those made from kerosene, as experience has fully demonstrated 

 the value of this product for insecticide work. In most instances either 

 the low or high grade can be used with equally good effect. Kerosene, 

 naphtha and some of the lighter products of petroleum have been used 

 pure. 



Naphtha and the lighter products of petroleum can be used in this man- 

 ner with safety to most plants, but the destructive effect on the insects 

 is by no means satisfactory. The use of kerosene pure is, however, at- 

 tended with danger and should never be undertaken except in a small 

 way and with the utmost care. Finely atomized, I have employed it with 

 some success, especially on oranges and certain conifers in years gone 

 by, before the emulsions were discovered. 



Kerosene Emulsions. — The ease and practicability of emulsifying and 

 diluting kerosene to any desired strength have been so fully demon- 

 strated in the course of the work of the division of entomology under 

 my direction that there is no longer need of attempting its use pure. 



The methods of emulsification have been so fully set forth elsewhere 

 that it is unnecessary to undertake their discussion here more than 

 in the nature of general instructions. 



An emulsion, if properly made, always contains a greater per cent, 

 of kerosene than of the other ingredients. This per cent, may vary 

 from 60 per cent, to 90 per cent., but experiment has shown that 66 per 

 cent kerosene will give the most satisfactory results. 



The formula for the preparation of kerosene emulsion ordinarily 

 recommended by me is the one originated by my former agent, Mr. H. 

 G. Hubbard, in his work against orange insects. It is as follows : 



Kerosene 2 gallons = 67 per cent. 



Common soap, or whale-oil soap | pound ) •>•> ,>„^ ^^^.^^ 



Water 1 gallon ^ — -i^M'er cent. 



Dissolve the soap in the water by heating and add the solution, 

 boiling hot, to the kerosene and churn the mixture by means of a 



