UNITED STATES 



DEPARTMENT OF AGRICULTURE 



DEPARTMENT CIRCULAR 266 



Washington, D. C. 



1923 



DISPERSION OF THE^^»^ 

 WEEVIL IN,1922i"«^-^o;^>\ 



^^n 4 ' 1923 



F. F. BONDY, R. C. GAINES, W: B. WILLi^MglSiiid('M./S*|jlgU]>^^^^^ 



Bureau of Entomology. 



n"'^/'^ 



The boll weevil has now spread to the point where determination of its 

 annual dispersion in many districts is largely a question of finding the last 

 cotton fields. The principal features of the weevil movement in 1922 were the 

 loss of territory in the western portion of the line through Texas and western 

 Oklahoma, and the gain in the eastern territory, particularly in North Caro- 

 lina. The loss in the west was due to a combination of factors, but very 

 largely to climatic conditions, which were exceedingly unfavorable for the 

 multiplication of the weevil. In much of this territory it was exceedingly dry 

 throughout the summer of 1922, and weevils thus became rather scarce, and in 

 some districts were apparently practically eradicated. It is probable that for 

 some years to come at least there will be more or less of this shifting back and 

 forth in these particular districts, with a westward movement of the weevil 

 following wet summers and a recession following drought. 



In examining the line marking the limit of weevil dispersion in 1922 (Fig. 1), 

 we find that from the point where it turns eastward in Major County, Okla,, it 

 follows the limit of cotton cultivation across northern Oklahoma, Arkansas, 

 Missouri, and Kentucky. In Tennessee the limit of cultivation is reached in 

 every instance, except for some little territory around Rutherford County. All 

 fields in Georgia and South Carolina were infested, even outlying small patches 

 planted at a considerable distance up in the mountains. In North Carolina the 

 limit of cotton cultivation is reached except for Currituck County, which is 

 the extreme northeastern county of the State. In addition the line bulges across 

 the North Carolina boundary at one point to include a small amount of terri- 

 tory in Virginia. In other words, the weevil has now reached practically the 



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