UNITED STATES DEPARTMENT OF AGRICULTURE 
BULLETIN No. 824 
Joint Contribution from the Bureau of Chemistry, 
CARL L. ALSBERG, Chief, and the Insecticide and 
Fungicide Board, J. K. HAYWOOD, Chairman 
S&9*^fL 
Washington, D. C. 
PROFESSIONAL PAPER 
June 3, 1920 
INSECT POWDER. 
By C. G. McDonnell, Chief, R. C. Roark, Assistant Chemist, Insecticide and Fungicide 
Laboratory, and G. L. Keenan, Microanalyst, Microchemical Laboratory. 
CONTENTS. 
Page. 
Purpose of investigation 1 
Definition 1 
History 2 
Cultivation and harvesting of insect flowers . . 4 
Preparation of insect powder 10 
Effect 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 
How to detect adulteration— Continued. 
Chemical methods 
Summary of methods 
Authors' method 
Active principle of insect powder 
Previous investigations 
Experimental work 
Distribution of the active principle in Chrys- 
anthemum cinerarisefolium 
Summary 
Bibliography 
Page. 
32 
45 
46 
65 
65 
74 
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 this 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) x recognizes as insect powder an insecticide 
made from the powdered flower heads of the following species of 
Chrysanthemum : 
1. Chrysanthemum {Pyrethrum) cinerarisefolium (Trev.) Bocc. 
2. Chrysanthemum (Pyrethrum) roseum Web. & Mohr. 
3. Chrysanthemum Marshallii Aschers. (synonym, Pyrethrum car- 
neum M. B.). 
1 References given by number to bibliography on p. 83. 
139815°— 20— Bull. 824 1 
