INSECT PEST SURVEY BULLETIN 
Vol. 19 Supplement to Number 9 December 20, 1939 
COLONIZATION OE EUROPEAN CORN .BORER PARASITES IN 1939 
C. A. Clark and W, G. Bradley, Associate Entomologists 
Division of Cereal and Eorage Insect Investigations 
Bureau of Entomology and Plant Quarantine 
United States Department of Agriculture 
During the 1939 season a total of 81,452 adult parasites, including 
C he 1 onus annul ipes Wesm. , Macrocentrus gifuens is Ashm. , Inareolata punctoria 
Roman, Lydella grisescens R.D., and Phaeogenes nigrjdens Wesm., were shipped for 
release against the European corn borer ( Pyrausta nubilalis Hbn. ) in the United 
States. The fcctal number actually released was 80,694, of which 75 » 0^6 were the 
egg- larval parasite C. annul ipes . 
The mortality in all shipments wa.s 753 adults, or 0.9 percent of the 
81,452 handled. The highest average mortality for any species (5*3 percent) 
occurred, as previously, with the delicate braconid M. gifuens is . The mortality 
in the large shipments of C_. annul ipes was 0* 6 percent. There was no mortality 
in the transfer of _I. punctoria , L. grisesqens . or P. nigridens . but these para- 
sites were taken only a short distance by car from the Moorestown, N, J. , labora- 
tory. 
All shipments were made in screen-sided metal cans wrapped in wet cloth, 
with 25 O adult parasites per can. Consignments of C he 1 onus annul ipes to the 
eastern or multiple-generation area wer ^ sent in iced shipping containers by 
railway express from the Toledo, Ohio, corn-borer laboratory. Shipping container? 
utilized are described in Bureau of Entomology and Plant Quarantine ET Circular 
77* Shipments other than those of C_. annul ipes to the eastern area were made in 
iced containers transported by automobile. 
In previous years the cloth-wrapped cans had been placed in individual 
corrugated cardboard cartons. In 1939 this carton was dispensed with for all shi] 
ments of C_. annul ipes from Toledo, bhus reducing weight and space requirements. 
That no harmful effect resulted from the omission of the corrugated cartons is 
evidenced by the low mortality sustained by this species. 
Table 1 lists the parasite shipments made in 1939 mnd gives the mortality 
for each shipment. 
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