I- IT SECT PEST SURVEY BULLETIN 
Vol. 20 
Supplement to No. 9 
December 1 , 19^0 
THE YIELD STATUS OF PAPAS ITES OF THE EUROPEAN CORE EORER A.T THE 
CLOSE OF THE 1939 SEASON 
By W, 0, Bradley, associate entomologist, 
and C, A. Clark, associate entomologist, 
Bureau of Entomology and Plant Quarantine 
United States Department of Agriculture 
Surveys to determine the current status of parasites of the European corn 
borer were conducted in the fall of 1939 at a. time when the seasonal relation- 
ship between the host and parasite had reached equilibrium. The sampling 
method utilized consisted of collecting a unit number of living borers and 
borers killed by parasites in the field prior to collection. This unit number 
was approximately 100 , except in certain collections where the adequacy of a 
smaller number was being tested, . The location of the fields from which samples 
were to be taken was determined in most instances by the use of polar coordinat 
or transect designs centering at the release point to be examined. The total 
number of larvae . collected in the Lake States and Eastern States areas was 
30 , 3 SH. Summaries of the results .of . observations in both areas are given in 
tables 1 and 2 , 
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LIBRARY 
STATE PLANT BOARD 
