298 INSKCTICIDAL MATERIALS AND PRACTICES 



3. Dry, diluted witli flour or any light and fine powder. The 

 poison may be used in the proportion of 1 part to from 6 to 30 of 

 the diluent. 



4. In fumigation. It may be scattered directly upon coals, or 

 made into small balls by wetting and molding with the hands and 

 then set upon coals. This is a desirable way of dealing with 

 mosquitoes and flies. 



5. In alcohol. (1) Put a part of pyrethrum (buhach) and 4 

 parts alcohol, by weight, in any tight vessel. Shake occasionally, 

 and after eight days filter. Apply with an atomizer. Excellent 

 for greenhouse pests. For some plants it needs to be diluted a 

 little. (2) Dissolve about 4 ounces of powder in 1 gill of alcohol, 

 and add 12 gallons of water. 



6. Decoction. Whole flower-heads are treated to boiling 

 water, and the liquid is covered to prevent evaporation. Boiling 

 the li(iuid destroys its value. 



Good insect-powder can be made from Pyrethrum roseum, and 

 probably also from P. cinerariwfoliuni, grown in the home 

 garden. 

 Resin and fish-oil corn-pound. — Ten pounds of resin ; 1| pounds of 

 fish-oil, 3 pounds of caustic soda, and enough water to make 50 

 gallons. 



Break the resin into small lumps, and place it together with the 

 caustic soda in the boiler, with three or four inches of water. 

 Stir till the resin is dissolved ; then add about one-fourth of the 

 required water and boil one-half hour. Place in the spray tank 

 and add the rest of the water. 



Used in California against the cottony cushion scale and the 

 brown apricot scale. 

 Soaps, whale-oil, or fish-oil soap. — Soaps are effective insecticides for 

 plant-lice. Dissolve in hot water and dilute so as to obtain 1 

 pound of soap for every 5 or 7 gallons of water. Commercial 

 whale-oil or fish-oil soaps frequently injure tender foliage be- 

 cau.se of the free alkali which they contain. 



An excellent fish-oil soap free from uncombined alkali may be 

 easily prepared at home, as follows : 



Six pounds of caustic soda ; U gallons of water ; 22 pounds 

 of fish oil. 



