12 



weather conditions. The larvse of this brood are often quite nu- 

 merous on alfalfa and in a few instances do serious damage to very 

 late cotton and corn. The larvae of this generation usually form 

 somewhat deeper cells than those occurring earlier in the season and 

 for the most j)art they pass the winter as pupse. However, a few 

 moths may emerge, giving rise to the larvae found in very late com 

 and gardens up to the time of heavy frosts. The number of annual 

 generations varies in the cotton belt from four to six according to 

 the latitude. 



EXTENT OF INJURY. 



Severe injury to cotton is confined largely to the western portion of 

 the cotton belt. During the past few years Texas has suffered by far 

 the greatest loss of any State from bollworm ravages. Yet the losses 

 due to bollworm depredations in Louisiana, Indian Territory, Okla- 

 homa, Mississippi, and Arkansas are by no means small. 



A combination of circumstances in the western portion of the 

 cotton-growing area has resulted in theoretically almost perfect con- 

 ditions for bollworm development. The great increase in the cotton 

 acreage during the past few years has been due largely to the develop- 

 ment of lands west of the Mississippi on account of the westward tide 

 of immigration. Central and northern Texas have afforded a vast 

 practically unbroken area of cotton and the people in general have 

 looked upon cotton and corn as the only crops to be successfully grown 

 on a large scale. Hence the valuable practice of crop rotation has been 

 sadly neglected. Insufficient cultivation, due in part to the tenant 

 system so generally employed upon the large plantations in Texas, 

 and to the planting of an acreage of cotton too great for the working 

 force, and also the continued planting of run-down seed without 

 regard to earliness, prolificacy, or quality of staple, have each lent 

 their unfortunate influence in increasing the seriousness of the boll- 

 worm problem. 



The average annual injury by the bollworm to the cotton crop of 

 the United States is probably in the neighborhood of $12,000,000. 



INJTJIIY, 1903-1906. 



As has been pointed out, the extent of injury to cotton varies 

 greatly from year to year. From a study of conditions during the 

 past few years it appears that this depends mainly upon the relative 

 earliness of the cotton crop, together with weather conditions. The 

 amount of plowing done during the preceding fall and winter also 

 exerts a decided influence upon the extent of injury. 



During 1903 the cotton crop was exceptionally late; owing to 

 adverse weather conditions during the preceding fall and winter 



200 



