BULLETIN OF THE 



Contribution from the Bureau of Entomology, L. O. Howard, Chief 

 July 14, 1914. 



(PROFESSIONAL PAPER.) 



EXPERIMENTS IN THE DESTRUCTION OF FLY 

 LARVAE IN HORSE MANURE. 



By F. C. Cook, Physiological Chemist, Bureau of Chemistry, R. H. Hutchison, 

 Scientific Assistant, Bureau of Entomology, and F. M. Scales, Assistant 

 Mycologist, Bureau of Plant Industry, 



INTRODUCTION. 



The great activity in antifly campaigns in recent years, together 

 with the recognition of the fly as a disease carrier, has created such 

 widespread demand for some means of destrojdng the fly that this 

 investigation has been undertaken for the purpose of finding a chemi- 

 cal that would destroy this pest in its principal breeding place, 

 namely, horse manure, without injuring the bacteria or reducing the 

 fertilizing value of the manure. This work was undertaken in 1913 

 at the suggestion of Dr. L. O. Howard to Dr. C. L. Alsberg, who 

 has heartily cooperated in this study and secured the cooperation of 

 Dr. TV. A. Taylor. The entomological work was done under the 

 direction of Mr. TV. D. Hunter and the bacteriological work in co- 

 operation with the laboratory of Mr. K. F. Kellerman. It is the 

 purpose of this paper to review some recent experiments, the results 

 of which point to an economical, practical, and effective way of de- 

 stroying fly larvae by the chemical treatment of manure. A con- 

 sideration of the larvicidal powers of a number of chemicals more, 

 or less effective as larvicides, together with- an account of their effects 

 on the value of manure so far as may be estimated by chemical and 

 bacteriological analyses, is included. 



HISTORICAL. 



American workers were the first to attack the problem of the chem- 

 ical treatment of manure with a view to destroying fly larvae. Pio- 

 neer work of this nature was begun in 1897 by Dr. L. O. Howard, 

 who showed that kerosene emulsion, while effective with small 

 45780°— Bull. 118—14 1 



