Vol. IS 
Supplement to Number 9 
December 29, 1938 
THE FIELD STATUS OE PARASITES OE THE EUROPEAN COM BORER 
•IN THE EALL-OE 193.7 . 
W. G. Bradley and C. A.- Clark 
Bureau of Entomology and Plant Quarantine 
United States Department of Agriculture 
Surveys were conducted after the active season of 1937 both in the Lake 
States and in the Eastern States in order to determine the current status of 
parasites of the European corn borer, with special emphasis on species that 
have been imported and released at various localities in the infested area. 
The field collecting of material for subsequent laboratory handling was re- 
stricted to localities in the vicinity of points previously selected for 
testing the reaction of parasites to environments in the United States. 
Each of the surveyed localities was sampled by the section-random sampling 
method, the location of samples being determined by the use of polar 
coordinate or transect designs of a type suitable to the objectives sought 
at each point. 
In the Lake States area collections were made at 5 colony sites, and 
a special survey was made along the western shore of Lake Erie, including part 
of the Maumee River Valley, to determine the dispersion of the tachinid para— 
site Lydella stabulans grisescens R, D. from the Jerusalem Township, Lucas 
County, colonization point in Ohio and the Monroe and Erie Township, Monroe 
County, points in Michigan. One hundred eighty-one samples, averaging 81,6 
borers each, or a total of 15,666 larvae, were collected at the various 
survey points . 
In the Eastern States surveys were made at the following points? 
Malden, ^ in ^Middlesex County, and Taunton, in Bristol County, Mass,; East 
Hartford, in Ha-rtf ord County, Conn. ; Atlantic Township, in Monmouth County, 
N. J. ; and Lee District, in Accomac County, Va. 
ihree hundred eighty-six samples, averaging 97*8 borers each, or a 
total of 37,73b larvae, were collected at the various survey points in both 
area . Tne results of observations in the two areas are summarized in 
tables 1 and 2. 
