PYRETHRUM AS Alif INSECTICIDE. 37 



Since the experiments of Mr. Saunders, previously referred to, 

 whereby it was shown that Pyrethrum could be employed against some 

 of our out-door insect pests, other experiments in continuance have 

 been made which have so extended its range of usefulness as to lead 

 us to believe that we have but begun to learn its value as an insecti- 

 cide. Under the demand which is springing up for it, it is being ex- 

 tensively cultivated in this country, mainly by Mr. Milco (a native of 

 Dalmatia), near Stockton, California, and an article is being produced 

 by him from the Pyrethrum ciiieraruefolium and sold under the 

 trade name of " Buhach," whicli is represented by those who have 

 thoroughly tested it, to be superior to much of the imported Dalma- 

 tian powder. The high cost of the imported powder (about $1.25 per 

 pound) has been hitherto an obstacle in the way of its use, but Mr. 

 Milco, from the facilities which he has for its production, promises 

 shortly to place it in market at a price which will admit of its general 

 use. 



The Department of Agriculture has also shown a commendable zeal 

 in importing the seed and distributing it, through the Entomological 

 Commission, to numerous persons in the United States, with the request 

 that experiments be made in its cultivation in various localities and 

 under different conditions, in accordance with detailed instructions 

 given. It is hoped that some one of the species will be found to admit 

 of such easy culture that it may be grown by farmers and others for 

 domestic use. The circular recently issued by Commissioner Loring 

 contains a statement of Professor Riley, giving a histor}' of Pyrethrum, 

 its method of cultivation, its preparation for use, its uses as an insecti- 

 cide, and modes of application. From the latter, we extract the fol- 

 lowing: 



Pyrethrum can be applied: — 1, as dry powder; 2, as a fume ; 3, as an alcoholic 

 extract diluted ; 4, by simple stirring of the powder in water; 5, as a tea or decoc- 

 tion. 



1. Application as dry powder. — It is generally used without diluent, but if un- 

 adulterated and fresh (which it not often is, as retailed by druggists), it may be 

 considerably diluted with other pulverized material, without losing its effect. 

 For this purpose flour seems to be the best, but finely-sifted wood ashes, saw- 

 dust from hard wood, etc., or any substance that will mix well with the powder, 

 will answer. If the mixture is applied immediately after preparation, it is always 

 less efficacious than when left in a perfectly tight vessel for twenty-four hours or 

 longer before use. Experiments have shown that one part of the powder to 

 eleven of flour were required to kill the cotton-worm, when applied immediately 

 aiter its application; but when it had been kept in a tight glass jar for about two 

 days, double the amount of diluent (twenty-two pounds of flour) sufficed to kill 

 most of the average-sixed worms with which it came in contact. For very young 

 cotton-worms, a mixture of one part of Pyrethrum to thirty parts of flour, and 

 applied one day after preparation, proved most efiective, hardly any of the worms 

 recovering. 



