354 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1944 
come immune or resistant to specific compounds and that such immu- 
nity or resistance has been transmitted to their offspring. 
Increased ability to survive in spite of insecticide treatment has 
been exhibited by a number of different insects, including the Cali- 
fornia red scale, Aonidiella awrantii (Mask.), certain strains of which 
are much more resistant than others to fumigation with hydrocyanic 
acid. The tendency toward the segregation of races within economic 
species has been thoroughly reviewed by Smith (1941). 
The evidence just cited indicates that, instead of remaining con- 
stant and static while the evolution of control measures was going on, 
the codling moth as a species has undergone considerable adaptation 
or evolution on its own account in the direction of greater ability 
to survive in the presence of insecticides. The segregation of resistant 
strains, together with certain practices on the part of the fruit indus- 
try, have permitted the insect to maintain its position as the most seri- 
ously destructive pest of the apple in spite of the development of 
control by insecticides to a high degree of efficiency, at least in the 
application and maintenance of heavy deposits of insecticides during 
the periods when needed. The codling moth is only one of the several 
insect pests known to have undergone development in this general 
direction, and many other insects may be developing in a similar 
way, but at a slower rate. It is evident that ultimately insecticides 
or other control measures that are less selective in their action will 
have to be used for the control of the codling moth, or perhaps the 
problem can be solved by occasional changes from one insecticide to 
another that is selective in a different way. Whatever the eventual 
solution of the problems that have grown out of the evolution under- 
gone by the codling moth, the entomologists will undoubtedly be able 
to meet this challenge to their ingenuity and resourcefulness, and 
any solution of this particular problem may point the way to means 
of meeting similar problems with other insect pests as such problems 
arise. 
LITERATURE CITED 
BURRELLE, JOSEPH. 
1840. On the Curculio. New England Farmer, vol. 18, No. 48, p. 398. 
CoLLINs, DONALD L. 
1934. The occurrence of Ascogaster carpocapsae in illuminated and sprayed 
areas of an apple orchard. Journ. Econ. Ent., vol. 27, No. 2, pp. 
379-382. 
Coox, A. J. 
1880. New method of fighting certain injurious insects. American Ent., vol. 
3, No. 11, pp. 263-264. 
Cox, JAMES A. 
_ 1982. Ascogaster carpocapsae Viereck, an important larval parasite of the 
codling moth and oriental fruit moth. New York Agr. Exp. Stat. 
Techn. Bull. 188, pp. 3-26. 
