Washington, D. C. ¥ Issued June, 1920; revised April, 1926 
INSECT POWDER 
By C. C. McDonneE tu, Senior Chemist, R. C. Roark and F. B. LaForas, Asso- 
ciate Chemists, Insecticide and Fungicide Laboratory, and G. L. KErEnan, 
Associate Microanalyst, Microchemical Laboratory, Bureau of Chemistry 
CONTENTS 
Page Page 
PUDpPOSelOl mMVEStigablones seo. 25 eos sete 1 | How to detect adulteration—Continued. 
IDisra bony eitoy also ee ne PREY ene eae, Bip 1 Chemical’ methodsss= ek ee 26 
SEO ee eee ere en 2 UMM arycOMmMeragoGse- ss oe eee 38 
Cultivation and harvesting of insect flowers _ 4 Wiriters sm eb hod 222s tert hoe bee pee ees 38 
reparation of insect powder.___-.---------- 9 | Active principle of insect powder_______----_- 59 
Effect of insect powder on insects__.___--_-__- il Previous investigations___.._..___-______ 59 
Hifect of insect powder on animals___________ 12 Experimental works. 2 soe eee 67 
Aduiteration of insect powder___-_--------_-- 14 Distribution of the active principle in Chrys- 
How to detect adulteration________._-___---- 17 anthemum cinerarixfolium_____-_---_----___ 75 
Physiological methods___-___-.---------- DL7 EPs HARSH D NS GE COE cA ae et ei a a Nae ee Ti 
Microscovical methods__-.__-____=------ LOS Bibliography as =) 2-2 lesce tee eee es ae ee ee 78 
PURPOSE OF INVESTIGATION 
Insect powder, has been widely adulterated, much to the detriment 
of the industry.. The mest serious form of this adulteration has been 
the addition of the powdered stems of the plant to the powdered 
flowers, which, in some cases, has been carried to complete substitu- 
tion. The work reported in this bulletin was undertaken for the 
purpose of devismg methods for the quantitative determination of 
such adulteration, of determining reasonable allowances for stems 
and acid-insoluble ash in insect powder, and of isolating and deter- 
mining the chemical nature of the active principles of 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 (Pyrethrum) cinerarixfolium (Trev.) Bocce. 
2. Chrysanthemum (Pyrethrum) rosewm Web. & Mohr. 
3. Chrysanthemum Marshallia Aschers. (synonym, Pyrethrum car- 
neum M. B.). 
1 Numbers (in italic) in parentheses refer to the bibliography (p. 78). Where the letter ‘‘S” is used 
reference is made to the supplemental bibliography (p. 92). 
70572°—26——1 
