28 
BULLETIN 1397, U. S. DEPARTMENT OF AGRICULTURE 
2,500 feet to about 4,000 feet above sea level. A careful study made 
in the El Paso Valley shows that there has been no noticeable 
increase in the amount of infestation during the last four years. 
These conditions greatly minimize the danger from the western 
infestation. The experience of several years shows that it is per- 
fectly feasible to eliminate practically all danger of spread to other 
regions. There is a chance, however, that this spread may occur 
despite all precautions, and it is undoubtedly wise to maintain the 
restrictions with the utmost vigor. 
On the whole, the conclusion seems to be warranted that the work 
done has resulted more succesfully than in the beginning was thought 
possible, and fully justifies the efforts and expenditures which have 
been made. This work must be continued, however, by preventing 
any possible recurrence in the districts where infestation has been 
found, by being ready to handle any undiscovered infestations in the 
Cotton Belt proper, by minimizing as far as possible the danger of 
the spread of infestation from the western areas, and by taking every 
precaution against new infestations from Mexico. 
