Insecticides. 13 



Pyrethrum, continued. 

 Persian insect-powder, made from the heads of Pyrethrum 

 roseum, a species now cultiYated as an ornamental plant. 

 The plant is native to the Caucasus region. 

 Dalmation insect-powder, made from Pyrethrum cinerarice- 

 * folium. 



BuHACH, made in California from cultivated plants of P. cincra- 

 ricefolium. 



When fresh and pure, all these brands appear to be equally 

 valuable, but the home-grown product is usually considered 

 most reliable. Pyrethrum soon loses its value when exposed ' 

 to the air. It is used in various ways : 



1. In solution in water, 1 ounce to 3 gallons. 



2. Dry, without dilution. 



3. Dry, diluted with 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 one part of pyrethrum (buhach) and 

 four 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 giU of alcohol, and add 12 gallons of water. 



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

 water and the liquid is covered to prevent evaporation. 

 Boiling the liquid destroys its value. 



7. Water extract. Pour 2 quarts hot water through about 

 a half pound of pyi'ethrum, held in a coarse bag, and then 

 add cold water enough to make 2 gallons, and it is well to 

 stir in the powder itself. For aphis and cabbage-worms. 

 It will keep but a few days. Or the extract can be made as 

 follows : Make a paste of 2 tablespoonfuls of pyrethrum by 

 adding water. Stir this into 2 gallons of water and apply 

 with a fine nozzle. This is recommended for the rose-chafer. 



8. Pyrethro-kerosene emulsion. See under Kerosene emul- 

 sion. 



