123 



quent picking up of the squares infested by hibernated weevils in the 

 spring, and is far more thorough as a means of reducing the numbers 

 of the weevil than is the practice of picking hibernated weevils from 

 the } 7 oung plants. 



Early destruction of the stalks is essential to the greatest success of 

 any system of controlling this pest. All other practices recom- 

 mended — early planting of early maturing varieties, thorough culti- 

 vation, fertilization, etc. (see p. 163) — though very valuable in securing 

 the crop, are perhaps of greatest value because they prepare the way 

 for this early destruction which so reduces the actual number of wee- 

 vils hibernating successfully that the other recommendations may 

 yield their best results. Since the earliest investigations made by this 

 Bureau upon the boll weevil, it has been recognized that this practice 

 is of the first importance, and the experience of recent years has but 

 added certaint}^ to this conviction. Planters have, however, been slow 

 to change their methods of cultivation, but enough have adopted the 

 recommendation to prove its efficiency. It must not be thought that 

 the procuring of the immediate crop is the only desideratum. Early 

 and complete destruction of stalks is undoubtedly the most important 

 single element insuring success for the sitvsequent year. 



DISSEMINATION. 



Dissemination, in the broad sense of the term, may be considered 

 as including all means or methods by which the weevil is spread to new 

 localities. In the following paragraphs, under the subject of migra- 

 tion, are included those factors by which dissemination is accomplished 

 through some effort upon the part of the weevil itself. 



ARTIFICIAL AGENCIES. 



Among these agents will be enumerated the principal factors assisting, 

 either directly or indirectly, in the movement of the weevils apart 

 from their own efforts. Two principal lines of spread will be found 

 along railways and watercourses. Between localities separated by 

 short distances traffic along highwa}^ is probabty a large factor, and 

 over longer distances the usual means of commercial traffic must be held 

 responsible. Shipments of cotton, whether for ginning or in baled 

 condition, are likely to carry many weevils. Shipments of seed for 

 planting coming from infested localities are almost certain to carry 

 weevils, and shipments of seed to oil mills may also assist in scattering 

 them. The pests are often carried far outside of infested regions in 

 the shipment of seed to northern and eastern oil mills. From the mills 

 they are carried to the farmers in the hulls or other by-products 

 used for feeding cattle. Many of the isolated colonies in northern 

 Texas originated in this manner. 



