SCREWWORM ERADICATION—KNIPLING 417 
ments must be met, however. These have already been discussed in 
some detail (Knipling, 1955). The major requirements are (1) a 
method of causing sterility in the insects without seriously affecting 
survival and mating behavior, (2) practical methods of producing 
Jarge numbers of sterile insects, (3) adequate dispersal of the in- 
sects released so that they will mix with the natural population, and 
(4) no danger of damage to crops, animals, or man by the insects 
released. Contrary to statements in the literature, single mating 
habits of the insect species is not necessarily an essential requirement. 
Research on the oriental, Mediterranean, and melon fruitflies, 
which the Entomology Research Division has had under way for 
several years at its Honolulu laboratory, is now being intensified 
to explore the possibility of utilizing the sterile-male method to 
eradicate or to prevent the spread and establishment of these major 
pests of fruit and vegetables. The work is being done under the 
general direction of L. D. Christenson. The research at Honolulu, 
under the immediate supervision of L. F. Steiner, shows considerable 
promise. Although all the fruitflies named have multiple mating 
habits, experiments in cages show that a ratio of about 10 sterile 
to 1 fertile male insect results in a high reduction in biotic potential 
of the flies. Methods of rearing fruitflies in the laboratory on a 
large scale have been developed. The seasonal population trends 
for fruitflies show wide variations in most infested areas. The use 
of bait sprays or male lures has been found to reduce existing popu- 
lations drastically, if necessary. The insects are also of sufficient 
importance to warrant a substantial investment in eradication pro- 
grams. These factors all suggest that full exploration of the sterile- 
male method for fruitfly eradication is justified. 
The Mexican fruitfly problem in California and Texas should also 
lend itself to practical solution by the sterile-male approach, and 
research to explore the possibilities is under way by the Division’s 
Mexico City fruitfly laboratory under the immediate supervision of 
W. E. Stone. 
NEED FOR ADDITIONAL RESEARCH 
Basic information is urgently needed on other major insects be- 
fore we can estimate the possibilities of the sterile-male method as a 
practical control or eradication procedure. In some situations the 
technique might be useful for control or elimination of the pink boll- 
worm, boll weevil, European corn borer, southwestern corn borer, 
sugarcane borer, codling moth, plum curculio, oriental fruit moth, 
tobacco and tomato hornworms, yellow fever mosquito, and no doubt 
other insects in the United States or other countries. The method 
might be useful in the following types of situations: (1) As an out- 
right eradication measure in areas of low insect populations; (2) as 
a final eradication procedure following drastic reductions of well- 
