
Ss 
Parasites of the pink bollworm,-—-L. W. Noble, H. B. Tittle, and J. M. 
Yeates report progress with the pink bollworm parasite investigations at 
Presidio, Tex. Two species, Microbracon brevicornis Wesm. ond Exeristes 
roborator Fab., were obteined from the’. Huropean corn borer laboratory at 
Monroe, Mich. , because they had been reported as parasites of the pink 
bollworm in Egypt! During September two colonies of M. brevicornis each 
consisting ef approximately 5,000 adults, approximately Oo percent of which 
were females, were released. From one point of liberation 7 specimens of 
Microbracon brevicornis were later obtained from pink bollworms. From the 
other point 31 M. brevicornis were obtained as well as ‘48 M. platynotae 
(Cush.) and 3 M. mellitor Say, two native parasites that appear to be adapt- 
ing themselves to the pink bollworn. Some difficulty has been encountered 
in obtaining sufficient Exeristes roborator for liberation in the ficld. 
At first the parasites were bred on pink bollworms that had been killed 
by hot water, as at the Monroe, Mich., laboratory these insects were brad 
from European corn borers that -had.been killed in hot water. Of the first 
generation, after switching from the corn horer as a host to the pink 
bollworm, ‘only 6.6 percent were females. Later better results were ob- 
tained by rearing Exeristes roborator on pink bollworms that had been pare 
lyzed by Microbracon brevicornis, In this way 30.4 percent females were 
obtained in the first generation and 36.6 percent in the second. The lew 
proportion of females is probably due to heavy mortality among them, Tle 
female larvae require more ‘food than the male lervae and the pink bollwam 
is considerably smaller than’ the European corn borer. It is hoped that 
the sex ratio will improve as the parasite becomes more adapted to the 
pink bollworm as a host. 
Boll weevil.~-Because of mild weather in the Atlantic coast region last 
winter boll weevils hibernated successfully in larger numbers than farther 
west. However, hot, dry weather during June reduced the boll weevil pom~ 
lation in the Eastern States so that less damage was caused in this region 
han in Texas, Oklahoma, Arkansas, Louisiana, and Mississippi. . In nearly 
all of the States the infestations were “spotted, eften being light on 
some farms and rather heavy on nearby farms,. Taking conlitions as a whole 
e all of the infested States, the boll weevil has not been as serious dire 
ing 1933 as during 1932, but has 2 ale more damage than during 1930 and 
ue 
A combination of factors this year were favorable to the early fall de- 
struction of the cotton stalks, one of the important methods of controlling 
the boll weevil. Cotton matured exceptionally early. The acreage was re~ 
duced by plowing under more than 10,000,COO acres during the summer, as part 
of the emergency cotton reduction campaign. There was an abundance of laber, 
and cotton was picked carlier than usual. A press release, "Early destruce 
tion cf cotton stalks means fewer boll weevils in spring," was issued on 
October 10, A statement on the same subject was prepared in cooperativen 
with the Radio Service of the Office of Information and was breadcast thr ough- 
out the South, When reports were received frem many sections that boll 
