INSECT POWDER. 13 



to 25 per cent of the powdered flowers remain in the sieve. This refuse 

 is not used in the best quality insect powder, but some manufacturers 

 repowdcr it and mix it with the fine good powder. Mixed with the 

 powdered leaves and stems of the Pyrethrum plant, it is used also as 

 a smudge for mosquitoes and flies. 



EFFECT OF INSECT POWDER ON INSECTS.' 



In the account of the discovery of the nature of insect powder by 

 Sumttoff (5) no details are given as to its use. It is simply stated 

 to be one of the most active means of protection against harmful 

 insects, ' ' attracting them by its characteristic odor and then numbing 

 and killing them, but to man and larger animals it is entirely harmless." 



Noodt (205), in 1858, wrote: 



The powder haa the property of numbing all insects in a short time and subsequently 

 killing them. Strewn in the room and in the bed it is a poison for lice, fleas, bugs, 

 flies, moths, etc. * * * . 



In the collection of insects it has been used for a long time not only to quickly kill 

 them but also to protect them against other insects, and it can be recommended not 

 only for this use but also in herbariums and other natural history collections, since 

 ants also quickly die from it. 



In 1858 Browne (38) recommended the trial of Persian insect 

 powder, or a decoction of it, against the scale of orange trees {Coccus 

 hesperidum), but the test does not appear to have been made. This 

 is the first use of insect powder against a definite insect suggested in 

 the United States, and the first time it is spoken of for use on fruit 

 trees. About the same time Willemot (294) records the results of ex- 

 periments on the destruction of noxious insects in France with 

 Pyrethrum. 



Glover (99), in 1864, described the first experiment recorded in 

 this country on the insecticidal efficiency of Persian insect powder: 



This powder had a curious effect on some Croton roaches we were experimenting 

 with; when sprinkled over them or placed in a circle and they made to pass over it, 

 for a few steps they appeared very lively, but soon staggered, and after a few struggles 

 fell over and soon ceased to live. 



Saunders (239), in 1879, was one of the first to describe the effect 

 of insect powder upon house flies and green aphis. About the same 

 time Carpenter (44) published the results of his experiments with 

 Pyrethrum on different insects. As a result of these experiments, he 

 states that "all insects having open mouth parts are particularly 

 susceptible to this powerful drug." Howard (138), in 1882, described 

 the effect of Pyrethrum upon the heartbeat of Plusia hrassicse (cab- 

 bage worm). 



A great amount of work has been done since 1879 by the United 

 States Department of Agriculture and the various agricultural ex- 



1 The statements given under this heading are merely quotations from the literature and are included 

 for their historic interest. They are not to be taken as representing the present opinion of the Department 

 of Agriculture concerning the efficacy of this product. 



