556 REPORT OP THE COMMISSIONER OF AGRICULTURE. 



centrated lye, each about 10 cents per pound; fish-oil, 35 cents per gallon. The ma- 

 terials used in making the soap above described made about 66 pints of soap, at a 

 cost of 37 cents, being a trifle over half a cent per pint. 



Two Pints of Soap in one Gallon of Water. — This proved fatal to all of the insects 

 with the exception of about 10 per cent, of the adult females. About three-fourths 

 of the eggs were destroyed, the solution having the property of hardening the egg- 

 masses. 



One Pint of Soap in one Gallon of Water. — This proved fatal to all of the insects 

 with the exception of about one-third of the adult females, but not more than one- 

 third of the eggs were destroyed. 



KEROSENE EMULSIONS. 



An emulsion was made by dissolving half a pound of hard soap in 1 gallon of 

 water, and adding it, boiling hot, to 2 gallons of the best grade of kerosene (150° fire- 

 test), and forcing this through a spraying-pump back agam into the vessel contain- 

 ing the solution. This was continued for about twenty minutes, when a very good 

 emulsion was formed. 



This emulsion was used in various proportions from 1 part of the emulsion to 6 

 l^arts of water, to 1 part of the emulsion to 18 of water. Neither of these solu- 

 tions produced an injurious effect upon the trees operated upon. 



One Part of the Emulsion to six Paints of Water. — This proved fatal to aU of the 

 insects with the exception of about 6 per cent, of the females before secreting the 

 egg-masses and 10 per cent, of those with egg-masses. Nearly all of the eggs were 

 killed. 



One Part of the Emulsion to nine Parts of Water. — This was fatal to only about 

 one-third of the adult females and a somewhat larger proportion of the young ones. 

 About four-fifths of the eggs were destroyed. 



A number of the egg-masses were immersed in the undiluted emulsion, and none 

 of the eggs thus treated hatched out. 



An emulsion of the same grade of kerosene as that used above was formed of 3 

 gallons of kerosene and 1 gallon of sweet milk. This formed a better and more 

 stable emulsion than the one made with soap-suds, but its etfects upon the insects 

 were not as good as those produced by the latter emulsion. 



A solution composed of 1 part of this emulsion to 6 parts of water killed nearly all 

 of the young insects, but proved fatal to only 10 per cent, of the adult females with 

 egg-masses. About one-haK of the eggs were killed. 



A thh-d emulsion was formed by emulsifying 2 gallons of the same gi-ade of ker- 

 osene as that used above with 1 gallon of soft soap dissolved in 2 gallons of water. 

 Considerable difficulty was experienced in forming a stable emulsion with these in- 

 gredients. 



This emulsion was diluted with water to such an extent that each 5 gallons of the 

 diluted wash contained 1 gallon of kerosene. This proved fatal alike to the insects 

 in all of their stages and also to their eggs. 



It was also used in such proportions that each 7 gallons of the diluted wash con- 

 tained 1 gallon of kerosene; this was fatal to aU of the insects with the exception 

 of a small number of the adult females with egg-masses; all of the eggs were killed. 



Even the strongest solution, containing 1 gallon of kerosene in each 5 gallons of 

 the diluted solution, produced no injurious effect either upon the trees or fniit; the 

 trees experimented on were small orange trees about four years old. 



Unlike the soap solutions, which penetrate the egg-masses and afterward harden, 

 thus preventing the escape of the young insects after hatching out, the kerosene de- 

 prives the eggs of their vitahty by penetrating first the egg-sacs and then the eggs 

 themselves. 



The cost of the kei-osene (150°) is about 20 cents per gallon when purchased in 

 large quantities. 



TOBACCO. 



Two pounds of tobacco leaves and stems were boiled in water until the strength 

 of the tobacco had been extracted; the solution when cold was diluted with water 

 and used in various proportions. 



When used in the proportion of 1 pound of the tobacco to each 2 gallons of 

 water, all of the insects were killed; about 3 per cent, of the eggs escaped injury. 



When used in the proportion of 1 pound of the tobacco to each 4 gallons of the 

 solution, it proved fatal to all of the insects with the exception of about 10 per cent, 

 of the adult females with egg-masses; about 95 per cent, of the eggs were killed. 



The strongest solution used, 1 pound of tobacco to each 2 gallons of water, pro- 

 duced no injurious effect upon the tree. 



Several egg-masses were immersed in a solution containing a pound of tobacco to 



