JOURNAL 
OF 
ECONOMIC ENTOMOLOGY 
OFFICIAL ORGAN AMERICAN ASSOCIATION OF ECONOMIC ENTOMOLOGISTS 
Vol. 17 DECEMBER, 1924 No. 6 
STUDIES OF THE PARASITES OF THE ALFALFA WEEVIL* 
IN EUROPE 
By T. R. Chamberlin, Assistant Entomologist, Bureau of Entomology, 
U. S. Department of Agriculture 
Abstract 
The following is a brief account of a study of the parasites of the alfalfa weevil, 
Phytonomus posticus (Gyll.), made in Europe by the writer between August, 1921, 
and August, 1923. The 14 primary parasites encountered are listed and their habits 
and distribution briefly considered. As a result of this work the writer has come to 
believe that most of the more important parasites could withstand a climate similar 
to that of Utah, which is in the middle of the weevil-infested territory in the United 
States, that the apparent effect of the parasites upon the number of weevils in Europe 
is not a true measure of what their effect would be in this country, and that it is 
advisable to attempt the colonization of the more promising ones. 
Early studies of the parasites of the alfalfa weevil were made in 
Europe by W. F. Fiske, H. S. Smith, and W. R. Thompson in the years 
of 1911, 1912, and 1913. This work was discontinued in 1913 and owing 
to the World War was not taken up again for some years. Later, as the 
weevil spread to new territory in the United States, interest in the 
parasites again arose. By 1921, one parasite which had been intro¬ 
duced in the early importations had spread from the original point of 
introduction near Salt Lake City, Utah, until it covered practically all 
the weevil-infested territory in the United States and probably had be¬ 
come a factor in reducing the injury of the weevil. Consequently, it was 
thought advisable to renew the study of other parasites in Europe before 
further importations were attempted. It was to make these studies that 
the writer went to Europe in 1921. 
Briefly, the main problem was to find new parasites, to establish the 
primary or secondary character of those involved, to determine if 
possible the importance of the parasites and the part they play in weevil 
*Phytonomous posticus (Gyll.)* 
623 
