Contribution from the Bureau of Entomology 
L. O. HOWARD, Chief 
Washington,D.C.  +=PROFESSIONAL PAPER July 20, 1915. 
FURTHER EXPERIMENTS IN THE DESTRUCTION 
OF FLY LARVA IN HORSE MANURE. 
By F. C. Coox, Physiological Chemist, Bureau of Chemistry, R. H. Hurcuison, 
Scientific Assistant, Bureau of Entomology, and I. M. Scaes, Assistant Mycolo- 
gist, Bureau of Plant Industry. 
INTRODUCTION. 
The results reported in this bulletin are a continuation of the inves- 
tigation dealt with in Bulletin No. 118, United States Department of 
Agriculture, inaugurated for the purpose of finding a substance that 
would destroy the larve of the house fly in their principal breeding 
place, namely, horse manure, without injuring the bacteria or reducing 
in any way the fertilizing value of the manure (Cook, Hutchison, and 
Seales, 1914). The work was conducted in cooperation by the 
Bureaus of Entomology, Chemistry, and Plant Industry at Arlington, 
Va., and New Orleans, La. The bacteriological work at New Orleans 
was done by Dr. William Seemann, dean of the Tulane School of 
Tropical Medicine, and thanks are due him for his cooperation. The 
entomological work at New Orleans was done by Mr. EK. R. Barber, 
scientific assistant, Bureau of Entomology. 
In Bulletin No. 118 it was suggested that manure be treated with 
borax immediately on removal from the barn in order to destroy the 
eggs and maggots of the house fly, and that borax be applied at the 
rate of 0.62 pound per 8-bushels, or 10 cubicfeet, of manure. Aslarge 
quantities of manure are used by truck growers, it was thought advis- 
able to include in that bulletin a warning as to the possible injurious 
action of large applications of borax-treated manure on plants. For 
the same reason it seemed desirable to find some volatile or other 
organic substance which would be effective as a larvicide, but without 
possible toxic action on vegetation. Largely with this object in view, 
the investigation was continued during 1914. The larvicidal value of 
some inorganic substances was also tested. 
Borax may be used with advantage for the treatment of outhouses, 
public dumps, and refuse piles of all kinds, cracks and crevices, floors 
of stables, and any accumulation of organic material which offers a 
92378°—Bull. 245—15——1 
