UNITED STATES DEPARTMENT OF AGRICULTURE 



BULLETIN No. 824 



Joint Contribution from the Bureau of Chemistry, 

 CAUL L. ALSBERG, Chief, and the Insecticide and 

 Fungicide Board, J. K. HAYWOOD, Chairman 



Washington, D. C. 



PROFESSIONAL PAPER 



June 3, 1920 



INSECT POWDER. 



By C. C. McDonnell, Chief, R. C. Roark, Assistant Chemist, Insecticide and Fungicide 

 Laboratory, and G. L. Keenan, Microanalyst, Microchemical Laboratory. 



CONTENTS. 



Purpose of investigation 1 



Definition 1 



History 2 



Cultivation and harvesting of insect flowers . . 4 



Preparation of insect powder 10 



EQect of insect powder on insects 13 



Effect of insect powder on animals 14 



Adulteration of insect powder 16 



How to detect adulteration 21 



Physiological methods 21 



Microscopical methods 23 



Page. 



How to detect adulteration— Continued. 



Chemical methods 32 



Summary of methods 45 



Authors' method 46 



Active principle of insect powder 65 



Previous investigations 65 



Experimental work 74 



Distribution of the active principle in Chrys- 

 anthemum cinerarisefolium 79 



Summary 82 



Bibliography 83 



PURPOSE OF INVESTIGATION. 



As in the case of many other products derived from natural sources, 

 sophistication and adulteration of insect powder have been largely 

 practiced, much to the detriment of the industry. The most serious 

 form of such adulteration has been the addition of the powdered 

 stems of the plant to the powdered flowers, which, in some cases, 

 has been carried to the extent of complete substitution. The work 

 reported in tliis bulletin was undertaken for the purpose of devising 

 methods for the quantitative determination of such adulteration and 

 for determining reasonable allowances in the amounts of stems and 

 acid-insoluble ash in insect powder. 



DEFINITION. 



The Insecticide and Fungicide Board of the United States Depart- 

 ment of Agriculture (143) ^ recognizes as insect powder an insecticide 

 made from the powdered flower heads of the following species of 

 Chrysanthemum : 



1. Chrysanthemum (Pyrethru7n) cinerarisefolium (Trev.) Bocc. 



2. Chrysanthemum (Pyrethrum) roseum Web. & Mohr. 



3. Chrysanthemum Marshallii Aschers. (s3aionym, Pyrethrum car- 

 neum M. B.). 



139815° 



1 References given by number to bibliography on p. 83. 

 -20— Bull. 824 1 



