- 632 - 
Table 6. Summary of shipments of European corn-borer parasites during the 
1938 season 
Species 
Paras ites 
shipped 
Mortality 
Microbracon brevicornis Wesm. . ' . 
Macrocentrus yifuensis Ashm. ....... 
Inareolata. punctoria Roman ........ 
Dumber 
io6,338 
29,073 
5,059 
4,018' 
384 
‘Dumber 
25 ,Uii 
520 
' 138' 
-• i4- 
• 4' 
Percent 
23.9 
1.8 
- ’ 2.7 
.3 
' • ' 1.0 
Tot a,X 
Average 
144. 872' 
26; 0811 
* * 4 
i * * 
18.0 
Shipments were made in screen-sided metal cans wrapped in moist cloth 
strips and enclosed in corrugated paper' cartons. Those consignments sent by air 
express had a thick outer wrapping of moistened cotton covered with cloth. Sail 
shipments ware made in insulated shipping boxes as described in Entomological 
Technique Circular 77, with provision for re-icing en route, at the end of 15 
hours, for all shipments requiring over 24 hours 1 shipping, time. ' Rail trans- 
portation, as described above, proved far superior to air shipments in lower 
mortality of parasites, lower cost, convenience, and safety. High mortality of 
C he 1 onus annul ipes occurred in shipments made by air express to Florida and 
Puerto Rico* The mortality incurred in- air shipments of this parasite was 35*9 
percent, partly due. to delays en route, compared to a' mortality of only 0.9 per- 
cent for shipments of this same species; by other means* While the average mor- 
tality for all shipments was IS. percent, this was due almost exclusively to the 
high mortality in the air shipments of C. annul ipes . mortality in shipments of 
all other species averaging only 1.8 percent. All shipments of C. t annul ipes 
were made from the Toledo laboratory and shipments of other parasites were made 
from the Moorestown, D. J., corn borer laboratory. 
During the 1938 colonization season a total of 63,485 parasites of 5 species 
were released in 30 counties in 8 States. A list of allreleases of European 
corn borer parasites made during 1938 is given : in table 7 "by States. Table 8 
lists all releases of parasites made against the corn borer in the United States 
up to December 31, 1938. 
A major objective of the 1938 parasite-colonization program was. the dis- 
tribution of the egg-larval parasite C he 1 onus annul ipes over a greater portion 
of the area infested by the multiple-generation strain of the com borer, as C_. 
annul ipes has become well established on this strain in southeastern Massa- 
chusetts and shows possibilities of becoming a -valuable factor in retarding the 
abundance of its host. Twenty-seven releases of this parasite, . including two 
liberations in Lucas County, Ohio, in districts whore the borer has recently been 
observed to pass through two generations annually, were made in 1938. A total 
of 28,257 adults of C. annul ipes were released. Map 1 shows the area colonized in 
1938 and in previous years. 
The releases of C_, annul ipes in the Eastern States were made a few days be— 
-tore the normal optimum date because conditions in April indicated an ea.rlier 
hos t-egg-depos ition period than usual. However, owing to unseasonably cool 
weather later, host oviposition was no earlier than normal. The releases of C. 
annul ipes in Ohio were well synchronized with the presence of host eyes in the 
field. 
