22 BULLETIN 824, U. S. DEPARTMENT OF AGRICULTURE. 



In 1880, Sayre (240) tested the effect of the flowers of Pyrethrum 

 roseum on flies and tadpoles. Unger (282), in 1888, while exam- 

 ining insect powders, made use of Kalbruner's "fly test." He, how- 

 ever, used a weighed amount of powder placed on a sheet of white 

 paper, over which the insect was imprisoned with a glass. Tested 

 against Blatta orientalis (Oriental cockroach or black beetle) and 

 Acarus farinse in this manner, the powder from both the P. cinerarise- 

 folium and the P. roseum killed the insects in about 45 minutes. 

 About the same time, Goff (104), in America, made tests with P. 

 cinerarisefolium grown in California and a powder prepared from the 

 flowers of Pyrethrum roseum, grown in New York from seed received 

 from the United States Department of Agriculture, to determine 

 the relative time required to paralyze flies. These tests indicated 

 that the powder made from P. roseum was slightly more effective. 



Hirschsohn (133), in 1890, while investigating the active constituent 

 of insect powder, tested the activity of the powder by trying it on 

 roaches. Two of the samples under investigation paralyzed roaches in 

 3 rninUtes. From his tests on Blatta orientalis j Thoms (275) con- 

 cluded that the physiological test was surer than either the micro- 

 scopical or chemical test in arriving at an estimation of the worth 

 of a powder. 



In 1895, JeUiffe (148) tested the action of insect powder on the 

 common house fly (Musca domestica), the Croton bug or cockroach 

 {Blatta germanica), the bedbug {Cimex lectutarius) , and some black 

 beetles (species undetermined). 



Dowzard (71), in 1899, conducted some tests on cockroaches. 

 Slaus-Kantschieder (261), in 1913, stated that although the micro- 

 scopical and chemical methods of examination furnish a basis for the 

 grading of insect powder, for the determination of the true value the 

 physiological test must be made. He conducts the test as follows: 

 A 25 cc. flask is taken, about 1 gram of insect powder added, the flask 

 then closed and shaken well, after which the flies are introduced. If 

 the powder is of good quality the flies wiU come to rest within one 

 half minute and die within 5 minutes. If the flies survive this period 

 the insect powder is to be considered as of low value and old. 



Kuraz (165) has recently tested a number of commercial samples of 

 insect powder, as weU as closed, half-closed, and open flowers, and 

 Pyrethrum stems grown at Korneuburg, near Vienna, according to 

 the method of Slaus-Kantschieder. The ordinary house fly {Musca 

 domestica) was used in these tests, and the time noted in which the 

 insect fell over on its back. The results are summarized in Table 2. 



