182 THE CHIEF SOUTHERN AGRICULTURAL CROPS 



these new methods requires the selection of the earli- 

 est possible strains of cotton, and of those which tend 

 to heavy flowering early in the season. The use of 

 a large percentage of phosphoric acid in the fertilizer 

 employed is also important, since this substance 

 tends to promote heavy fruiting and early ripening. 

 Heavy applications of nitrogen and potash, on the 

 contrary, have a tendency to prolong the growing 

 season and to retard the setting of the crop. Ex- 

 periments in Cuba have shown that even under 

 tropical conditions it may be possible to grow cotton 

 in spite of the presence of the boll weevil, by treating 

 it strictly as an annual crop, and promptly destroy- 

 ing the plants at the end of the picking season, 

 provided that the precaution is always taken of 

 destroying all of the half -wild native cotton through- 

 out a considerable surrounding area. 



The boll worm is closely related to the cutworms. 

 The young larvte bore into the bolls, and, after feed- 

 ing for a time, emerge and enter fresh bolls, the same 

 larva thus destroying several bolls in a few weeks. 

 Besides cotton, these insects bore into green toma- 

 toes in the same manner, being a very destructive 

 enemy of this crop in all parts of the South. The 

 boll worm is also the familiar corn worm so fre- 

 quently found entering the ends of the ears of green 

 corn. While these three are its usual food plants, it 

 is not confined to them, as it is occasionally found 

 boring into various other fruits and pods. Owing 

 to its habit of feeding so largely on the interior 

 tissue, this insect is very difficult to combat by the 

 use of insecticides ; in fact, no effective remedy has 



