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Published Quarterly by the 
PeleNcO lore SoU DU B.0O.N,5:.0:'C1 BEY 
2001 NorTH CLARK STREET, CHICAGO, ILLINOIS 
Number 58 June, 1946 
Effects of DDT on Wildlife in a Mississippi 
River Bottom Woodland* 
By Leo K. Coucu, U. S. Fish and Wildlife Service, Chicago, Illinois 
INTRODUCTION 
IT IS DISTURBING to find DDT (dichloro-diphenyl-trichloroethane) released 
for public use long before adequate research has revealed its limitations. 
Its promise as the ultimate Utopia in insecticides seems to overlook dangers 
to other forms of animal life. The effectiveness of DDT for household use 
in curbing flies, bedbugs, and mosquitoes, military use in controlling lice 
that spread typhus, and against insects of veterinary importance, has been 
demonstrated. In agriculture and forestry, potential dangers have not 
been fully appreciated. In fact, applications of DDT in the outdoors, 
whether on marshes, lakes, streams, on crop and pasture lands and in 
forested areas, present a serious threat to fish and wildlife species. Only 
now are we becoming aware of the possible misuse of this powerful 
chemical in the hands of the uninformed public. 
This paper covers observations before and after extensive applications 
of DDT on forested lands along the Mississippi River from August 5 to 
October 6, 1945. The area administered by the War Department is known 
as the Savanna Ordnance Depot Proving Grounds, located in northwestern 
Illlinois. Assistance of the Army Sixth Service Command, Chicago, and 
military personnel of the Ordnance Depot is gratefully acknowledged. 
Dr. E. M. Searls, entomologist for the Sixth Command, rendered personal 
aid in furnishing personnel, equipment and transportation, making it 
possible to collect considerable data over a wide area. Flyway Biologist 
Robert H. Smith assisted with observations at the October spraying. 
OBJECTIVES AND PLANS 
While this region along the Mississippi has not been classed in a 
serious malarial zone, the presence of malaria carriers among Italian 
prisoners of war caused Army authorities some concern over the possible 
spread to military and civilian personnel working on the post. Experi- 
ments were designed to test the airplane method of applying DDT for 
mosquito control. An invitation was extended to the U. S. Public Health 
*This paper was presented at the 11th North American Wildlife Conference, 
New York City, March 12, 1946. 
paed 
