REPRESSION. 155 



honest persons to suppose that the substances tney are applying have 

 killed it. Moreover, an insuperable difficulty that these special 

 preparations have encountered is the impracticability of the appli- 

 cation in the field. Hundreds of known substances will kill the 

 weevil when brought into contact with it. The difficulty is to apply 

 them in an economical way in the field. The claims made at different 

 times of the repellent power of tobacco, castor-bean plants, and 

 pepper plants against the boll weevil have no foundation whatever. 

 In fact, none of these plants has the least effect in keeping weevils 

 away from cotton. 



REQUIREMENTS OF A SATISFACTORY METHOD OF BOLL-WEEVIL 



CONTROL. 1 



The difficulties in the way of controlling the boll weevil lie both in 

 its habits and manner of work and also in the peculiar industrial 

 conditions involved in the production of the staple in the Southern 

 States. The facts that in all stages, except the imago, the weevil lives 

 within the fruit of the plant, well protected from any poisons that 

 might be applied, and in that stage takes food normally only by insert- 

 ing its snout within the substance of the plant; that it frequently 

 requires only 12 days for development from egg to adult, and the 

 progeny of a single pair in a season may exceed 3,000,000 individuals; 

 that it adapts itself to climatic conditions to the extent that the egg 

 stage alone in November may occupy as much time as all the imma- 

 ture stages together in July or August, are factors that combine to 

 make it one of the most difficult insects to control. It is, conse- 

 quently, natural that all the investigations of the Bureau of Ento- 

 mology have pointed toward the prime importance of methods of 

 control which involve no outlay for materials and very little for labor. 

 Methods which involve some direct financial outlay for material or 

 machinery are not in accord with labor conditions surrounding cotton 

 production in the United States. Moreover, the indirect methods 

 advocated are in keeping with the general tendency of cotton culture* 

 that is, to procure an early crop, and at the same time have the great* 

 advantage of avoiding damage by a large number of other destruc- 

 tive insects, especially the bollworm. Nevertheless it must not be 

 understood that attention has not been paid to the investigation of 

 means looking toward the direct extermination of the pest. Much 

 work has been done, but the results have all been negative. 



BASIS FOR MEANS OF REPRESSION. 



In spite of the many difficulties involved in the control of the boll 

 weevil certain generally satisfactory means of repression are at hand. 

 They consist of both direct and indirect means. Those of an indi- 

 rect nature are designed to increase the advantage gained by the 

 direct measures and to increase the effectiveness of the several natu- 

 ral factors which serve to reduce the number of weevils. Thus, the 

 control measures constitute a combination of expedients, the parts 

 of which interact in many ways. Naturally, the best results are 

 obtained when the planter can put into practice all of the essential 

 parts of the combination. 



1 This section is greatly modified from Bull. 51, Bureau of Entomology, pp. 160, 161. 



