26 



mixture applied at the rate of 15 pounds per acre. The general plan 

 adopted in all the poison experiments was to select two areas of from 

 3 to 10 acres each upon which the cotton was as uniform as possible, 

 then to apply poison to one, leaving the other as a check. 



At Ladonia and Paris 24 acres were poisoned, an equal acreage 

 being left unpoisoned as a check. A hand blower, mounted on a 

 wagon with wheels sufficiently far apart to include between them two 

 cotton rows, was- used in these experiments, while at Cooper a geared 

 blower was employed. Desirable results have attended the applica- 

 tion of poison in practically' every instance. The unfavorable results 

 shown in a few cases were attributable to unevenness of stand or to 

 a too late application of the poison. 



The results of the poison experiments at Cooper are given below : 



Table V. — Result.^ of experiments of the U. S. Department of AgriaiUure in poisoning 

 tlie bollworm, at Cooper, Tex. 



On plantation of — 



B. Kobertson . . . 

 T. C. Hunter ... 

 Fred Johnson . . 



N. P. RobertBon 



0) <U 



.Sop. 

 OS * OS 

 O 



Lbs. 



246. 5 



100.0 



81.6 



420.0 



$8.00 

 3.25 

 2.66 



13.66 







JO. 79 

 2.04 

 1.44 



11.24 



The above figures show a weighted net gain of $5.21 per acre upon 

 the four poisoned areas, as compared with similar adjoining areas 

 Avhich were not poisoned. 



The marked gain upon the plat receiA'ing two applications was 

 probably not due so much to its having received two applications 

 as to the exceptionally favorable conditions attending the poisoning. 

 The two fields showing the greatest gain per acre were smooth, so 

 as to admit of the easj^ manipulation of the large machine over the 

 entire area, while the others were more or less rough; the wind 

 was also favorable when the former fields were treated. A slight 

 shower preceded the second application upon the area on Mr. N. P. 

 Robertson's farm, thus causing the poison to adhere well to the 

 plants. 



During 1905, at Quinlan, Tex., about 50 acres were used in poison 

 experiments. In general, the results of these experiments were satis- 

 factory. Apparently no advantage was gained by making a second 



290 



