180 THE CHIEF SOUTHERN AGRICULTURAL CROPS 



The upland cottons are quite plastic and variable, 

 so that improved strains are readily secured by at- 

 tention to seed selection. Some of these better 

 strains now almost equal the Sea Island cotton in 

 length of fiber, and command a considerable pre- 

 mium over the common grades in the market. Sea 

 Island cotton is much less extensively cultivated, 

 and but few named varieties have been developed. 

 It has been found possible, however, to greatly im- 

 prove it by seed selection, and many of the more 

 prominent planters have special strains of their own 

 growing. The phenomenal success obtained by ex- 

 perts from the Department of Agriculture in select- 

 ing a strain of Sea Island cotton that is resistant to 

 the terrible wilt disease is one of the most striking 

 examples of the w^onderf ul possibilities that may be 

 secured by care in selecting the seed of our cultivated 

 crops. 



Diseases and Insects. — The insects attacking 

 cotton have been very thoroughly studied by the 

 entomologists of the United States Department of 

 Agriculture, and are fully discussed in their various 

 publications. The three most important are the boll 

 weevil, the boll worm, and the caterpillar. Of these 

 the boll weevil is by far the most destructive, and 

 threatens seriously to curtail production. This in- 

 sect is a native of Mexico, Central America, and 

 Cuba. It finally crossed the Rio Grande into Texas, 

 and for a number of years has been spreading 

 steadily northward and eastward, until it now 

 seems certain that it will eventually occupy the 

 entire cotton belt of the Southern states. So far 



