h. There would be justification for employing the sterile-insect-release method, even 

 if it were more costly than current ways to control or eradicate insect popula- 

 tions, if it provides advantages in overcoming hazards to man and his environment. 



i . Sterile insects to be released must not cause undue losses to crops or livestock, or 

 create hazards for man that outweigh the benefits of achieving or maintaining 

 population control. 



HOW STERILE INSECTS MIGHT BE EMPLOYED TO CONTROL 

 POPULATIONS OF CERTAIN SPECIES 



The foregoing discussion considers the principles involved, and the factors that 

 will determine the role of sterile insects in controlling insect populations. Every insect 

 problem requires a detailed analysis of the many factors already alluded to that have a 

 bearing on the method, and much research will be needed to develop the technique for 

 practical use. However, it might be helpful to consider specific insect problems and, 

 with the aid of hypothetical models, indicate how populations of these insects might be 

 controlled or eliminated by making sterile-insect releases. The writer has conducted 

 special studies on a number of important insects that have widely varying habits, in 

 efforts to appraise the role that sterile-insect releases might have in their control or 

 elimination. The insects considered include the boll weevil, the tobacco horn worm, and 

 tsetse flies. Factors considered and procedures followed in making appraisals will be 

 discussed in detail. There is no assurance that success will be achieved by the use of 

 the sterile-insect technique for these insects. However, on the basis of present concepts, 

 the writer believes that there is an excellent chance that the technique can play a major 

 role in eliminating or controlling populations of all three species. It might be stated that 

 a similar appraisal of the potential for the sterile-male method was made for eradicating 

 screw-worm populations long before the effectiveness and practicability of the method was 

 established. A vast amount of research by such able scientists as R. C. Bushland, 

 A. W. Lindquist, A. H. Baumhover, C. H. Husman, and others was required to develop 

 the techniques, and improvements are constantly being made by research and control 

 workers. However, practical experience has fully confirmed the hypotheses originally 

 established. 



Boll Weevil 



The boll weevil is among the most destructive of the insect pests in the United 

 States. Annual losses to cotton growers are estimated to average about $300 million. 

 In addition, growers spend an estimated $70 million each year to prevent even higher 

 losses. About 10 million acres of cotton are grown in areas infested by the pest. Cotton 

 is the chief host for the insect, and entomologists generally assume that the boll weevil 



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