402 



SOUTHERN FIELD CHOPS 



370. Spread of the boll-weevil. — Ordinarily the adult 

 weevil flies but a few rods at a time. However, when food 

 becomes scarce iu the fall, distances of as much as fiftj^ 

 miles are tr9,versed in a few days. This fall migration, a]> 

 parently in search of food, explains the rapid spread of 

 the boll-weevil. The weevil usuall}- advances about fifty 

 miles a j-ear. However, in 1909 its eastward spread across 



Fig. 177. — The ITind.=i Chain Cultivatok fou Tillage avd for 



DK.-VWING THE FALLEN SqU.\BES TO THE W.VTEB-FUEBOW. 



the southern part of Mississippi was more than tA\'ice this 

 distance, liringing the weevil at the end of 1909 to within 

 al)out ten miles of the Alabama line in the vicinity of iXIo- 

 l^ile. In the fall of 1910 this insect invaded several coun- 

 ties in the southeastern part of Alaliama. Probaldy its 

 extension northward will l)e somewhat less rapid than its 

 eastward spread. 



Crossing the Rio (irande from ^Mexico about 1S92 it 

 has persistently spread eastward and northward. The 

 niai) (Fig, 178) shows that by the close of 1909 the boll- 

 wee^'il occujiied the greater part of the cotton-growing 



