6 NATURAL CONTROL OF THE COTTON BOLL WEEVIL. 



ourkn()\vledf{e of every factor affecting, favorably or unfavorably, the 

 development and attack of the boll weevil must be made as complete 

 as is possible. While it may be impossible to increase the influence or 

 effectiveness of some of these factors, there is excellent promise that it 

 may be possible to utilize others to a far greater degree than has been 

 done in the past, because of our more exact knowledge of the nature of 

 their eflect upon the weevil and of the conditions under which the}' 

 produce most beneficial results. It is possible that by this greater 

 utilization of natural forces the damage annually done by the weevil 

 may be very materially decreased at little, if any, expense. 



By ''natural control" is meant the combined effect upon the weevil 

 of all natural enemies and of all conditions or forces in nature which 

 retard or prevent the development of the weevils and reduce the injury 

 which they might otherwise inflict upon the crop. These are, in gen- 

 eral, the factors which operate to produce and to preserve what is often 

 spoken of as ''the balance in nature." The principal factors are tem- 

 perature and moisture conditions in summer and in winter, the attack 

 of predaceous enemies or parasites, and the dependence of the species 

 upon a favorable condition of food supply. 



Since the beginning of the present cotton boll weevil investigations 

 in 1901, the work in the field has been continuously under the direc- 

 tion of Mr. W. D. Hunter, to whom is due credit for many of the sug- 

 gestions followed and for the breadth of scope which it has been possi- 

 ble to give to this particular portion of the investigation. Under his 

 direction the work has been planned and carried out under the imme- 

 diate supervision of the \\Titer. Nearly all of the special field agents 

 who have been in the investigation have had some part in the collec- 

 tion of material or in the examinations involved in securing the data 

 for this bulletin. Special acknowledgment is due to them for the 

 large amount of painstaking work without which this study could not 

 have ])een made sufficiently extensive to have been of practical value. 

 It gives the writer pleasure to acknowledge this indispensable assist- 

 ance by Messrs. W. W. Yothers, R. A. Cushman, A. C. Morgan, C. R. 

 Jones, W. D. Pierce, F. C. Pratt, F. C. Bishopp, W. H. Gilson. and 

 J. C. Crawford. 



W. E. H. 



