536 ON THE DESTRUCTION OF NOXIOUS INSECTS 



rapidly increasing. At present there are more than 20 villages in 

 the district of Alexandropol engaged in cultivating the plant and collect- 

 ing its flowers. The plants from -which this powder is produced, consist 

 of small perennial shrubs, from twelve to fifteen inches in height, hearing 

 fioweis an inch and a half in diameter, and resembling those of the 

 ox-eye daisy, (Chrysanthemum leucanthemum.) 



They grow on the mountains of the Caucasus at an elevation of 

 5,650 feet above the level of the sea, in a temperature of 68° 

 Fahr. They are of easy cultivation in gardens, and since their hardiness 

 has become known, they have been introduced into Germany, Holland, 

 and France, for the purposes of ornament, when they begin to flower 

 in June. They will flourish in any ordinary garden soil, and may 

 be propagated by layers as well as by seed. 



The parts of the plants from which the powder is made are the dried 

 flower-heads, gathered when ripe, on fine days ; and usually dried by 

 exposure to the sun ; but they have been found to be more serviceable 

 when dried in the shade, during which operation they are occasionally 

 turned. In the process of dessication they lose about 90 per cent. 

 When perfect])' dried, they are first comminated with the hand, and 

 then reduced to powder in a small mill. 



A quantity of these plants grown upon eighteen square rods is 

 estimated to furnish one hundred pounds of powder, which is best pre- 

 served in sealed vessels of glass. The application is made either as a 

 powder or as an infusion, though in the latter form it is more beneficial, 

 especially when intended fur the destruction of insects on plants. The 

 powder may be employed directly to the insects themselves, or in the 

 places which they frequent. They are attracted by its smell, become 

 stupified and immediately die. This substance may be employed with- 

 out injury to the larger animals, or to man. It is intimated that the 

 amount of this powder consumed annually in Fiussia alone is about 

 600 tons. 



The inhabitants of the Caucasus and adjoining countries who used 

 these powders had only a very limited knowledge of their plants, and 

 did not suspect that one among them, the Pyrethrum Willemoti, 

 Duchartre, would be called upon to render the most effective service to 

 agriculture and horticulture, achieving the preservation of food, wool, 

 furs, and the comfort of man and the domestic animals, &c. 



These powders had been introduced into France for several years 

 before a choice had been made among them, and the special import- 

 ance of this particular species recognised. The high price and the 

 numerous adulterations they have undergone, diverted the public from 

 this acquisition, and from a public appreciation of its efficacy. Submitted 

 to a close analysis, these powders as sold have been found to be mixed 

 with dangerous substances, which in due regard to public safety re- 

 quire to be vigorously excluded from sale. In them sumac powder is a 

 common ingredient from its close resemblance to the Pyrethrum powder, 



