12 RELATION OF DROUGHT TO WEEVIL EESISTANCE IN COTTON. 



stage is reached. The Aveevils begin b}' gnawing the terminal vege- 

 tative buds in the spring, before there are any flower buds to feed 

 upon. This hinders growth of the young plants and forces the 

 growth of A^egetative branches at the base of the plants instead of 

 allowing fruiting branches to be produced early in the season. 

 Weevil-infested fields of cotton can often be recognized, even at a 

 distance, by changes in habits of growth, before the dilTerences in 

 yield become apparent. Such expedients as the picking of the adult 

 weevils by hand and the poisoning of the leaf buds of the young 

 plants are much more advantageous early in the season, not only in 

 reducing the number of Aveevils, but in allowing the cotton to make 

 more rapid and normal growth. Yet it is very difficult to determine 

 how much advantage is secured from such efforts, owing to the great 

 variation in seasons and in the abundance of weevils in different 

 fields, or even in parts of the same field. 



Drought is more effective in holding weevils in check if the dry 

 weather begins before the cotton plants are large enough to proAade 

 the necessary food and shelter for the weevils. If the plants con- 

 tinue to make good growth during weather that is too dry for the 

 weevils to propagate, the crop can be set and brought to maturity 

 without serious damage, even in localities where earlier plantings 

 have suffered severely from the weevils. This explains the very great 

 advantage that is generally to be gained in dry regions by plowing 

 the land in the fall and maintaining the tilth through the winter 

 as a preparation for the planting of cotton, in order to have as much 

 moisture as possible available in the soil and thus enable a more con- 

 tinuous growth to be made during any periods of dry weather that 

 may occur in the early part of the growing season. 



With proper attention to the preparation of the land, cotton can 

 be grown even without irrigation in many districts of the South- 

 west that have been looked upon hitherto as hopeless deserts. The 

 drought -resistant qualities of the cotton plant are only beginning to 

 be appreciated, perhaps because the chief centers of production have 

 been located in humid regions. In localities where small supplies 

 of irrigation water can be developed they can probably be used to 

 much better advantage with cotton than with any other crop. The 

 general danger in irrigated regions is the excessive use of water. 

 The chief obstacle to the extension of cotton culture in the South- 

 Avestern States is the scarcity and high cost of labor, but the progress 

 that is being made in the invention of cotton-picking machinery indi- 

 cates that this limitation may be removed in the near future. 



220 



