INSECT PEST SURVEY BULLETIN 
Vol. 16 Supplement to No. 9 December 20, 1936 
COLONIZATION OF PARASITES OF THE EUROPEAN 
CORN BORER IN THE UNITED STATES in 1936 
By 17. 0. Bradleyi/Assistant Entomologist 
and E. 17. Beck, Junior Entomologist 
Division of Cereal end Forage Insect Investigations 
Bureau of Entomology and Plant Quarantine 
U. S. Department of Agriculture 
The activities in connection with the biological control of the corn 
borer as discussed in this report were directed from the laboratory for 
European corn borer research at Toledo, Ohio. 
The objectives of the program of 1936 were (l) the dispersion of 
Inareolata punctoria Roman, an ichneumonid attacking third-instar corn borer 
larvae and indigenous both to Europe and the Orient, over as much as possible 
of the infested territory not j>reviously colonized by this species; and (2) 
the testing in the more southern range of the borer of two species of para- 
sites, viz, Crem astus flavoor bitalis (Cameron), an ichneumonid of oriental 
origin attacking fourth-insta.r larvae, and Mi crog a ster tibialis Nees, a 
braconid attacking second-instar larvae and indigenous to Europe and the 
Orient. Previous releases of these two species had resulted in initial estab- 
lishment but not maintenance. 
Parasite material . — For the first time since the inauguration of the 
biological control program in 1920, it was deemed feasible to depend upon 
procuring a supply of the parasites most desired for dispersion purposes, 
from area.s where corn borer parasites were first released in the United States, 
From these areas, some 14,000 adults of I_. punctoria were obtained, thereby 
permitting an appreciable extension of the total area colonized with this 
species. Incidental to this work, adults of Ly dell a stabulans var. grisescens 
R. Deev. were obtained and were used for colonization in more or less isolated 
infested areas. A supply of M, tibialis was made available through the Divi- 
sion of Foreign parasite Introduction. The Entomological Branch of the Cana^ 
dian Department of Agriculture provided a supply of C. flavoorbitalis from 
Jl). XI. Jones, C A. Clark, E. D. Burgess, N. J. Nerney, and J. S. Mayfield 
assisted in the release of parasites in the regions of their respective 
assignments. 
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