8 BULLETIN" 731, U. S. DEPARTMENT OP AGRICULTURE. 



points a heavier infestation was produced by different seasonal con- 

 ditions, and pronounced results were secured from the poison. In 

 every case the experiments were conducted on comparatively small 

 areas, subject to a continual influx of weevils from surrounding un- 

 treated cotton, but in spite of this a very definite weevil control 

 resulted from poisoning. The open cotton in every case showed a 

 definite gain to the last row of treatment. The gains per acre ranged 

 from 250 pounds to 1,007 pounds of seed cotton. Views of two of 

 these tests are shown in figures 6, 7, and 8. 



It is, of course, impossible to estimate how much larger these 

 gains would have been if entire cuts or entire plantations had been 



Fig. .3.— View looking across rear end of poisoned cotton on Mound Plantation Cut No. 2, with poisoned 

 cotton on right of view and unpoisoned on left; second picking only, October 23, 1917, Tallulah, La. 



treated, and thus the inflow of weevils from unpoisoned cotton pre- 

 vented, but it is clear that these gains secured on small plats were 

 very conservative. In fact, this was brought out well by one large- 

 scale treatment described below. 



A LARGE-SCALE TREATMENT. 



About the middle of August the writer was requested to attempt 

 the control of the weevil on a large section of an Arkansas plantation. 

 This cotton was on very fair land, but had not been planted until well 

 along in May. Weather conditions then retarded it greatly and it did 

 not start setting a crop until about the latter part of July. About the 

 middle of August a fair crop of bolls was present, but the plants were 



