INSECTICIDES. 11 



thrips and lice on roses and other bushes. Apply when 

 the bush is wet. Useful for aphis on house plants. 



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 moulding 

 with the hands and then set upon coals. This is a desir- 

 able way of dealing with mosquitoes and flies. 



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

 and 4 parts alcohol, by weight, in any tight vessel. Shake 

 occasionally, and after 8 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 liquid destroys its value. 



7. Water extract. Pour 2 quarts hot water through 

 about a half-pound of pyrethrum, 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 

 EMULSION. 



Good insect-powder can be made from Pyrethrum 

 roseiim, and probably also from P. cineraricefolium, which 

 are grown in the home garden. 



Quassia. Boil 4 ounces of quassia chips 10 minutes in a gal- 

 lon of water ; strain off the chips and add 4 ounces of soft 

 soap, which should be stirred as it cools. Apply with 

 syringe or brush. Ten or fifteen minutes after it has been 



