21 



day, could, no doubt, be considerably increased. Below is the treat- 

 ment given and the results from the respective plats: 



Comparison of yiekh from plat sprayed with "green arseiioid," plat dusted, with Paris 

 green, and plat left untreated. 



Plat I, 3.89 acres, left untreated for comparison; yield of seed cotton pei 

 acre .-. , pounds . . 246. 



Plat II, 4.37 acres, treated with " green arsenoid, " 1 pound to 50 gallons water; 

 sprayed August 14, 28, and September 5; yield of seed cotton per acre, 

 pounds , 554. 8 



Increased yield of seed cotton per acre in favor of spraying.. pounds . . 308. 8 



Value of gain per acre, at 3 cents per pound of seed cotton $9. 26 



Cost of three sprayings per acre, including labor and poisons 2. 27 



Net gain per acre in favor of spraying 6. 99 



Plat III, 4.38 acres, dusted with Paris green, average of 3 pounds per acre; 

 poisoned August 15, 22, and September 4; yield of seed cotton per acre, 



pounds 460.21 



Increased yield of seed cotton per acre from poisoning pounds. . 214. 21 



Value of increase per acre, at 3 cents per pound of seed cotton $6. 42 



Cost of three dustings per acre, including labor and poisons 1. 98 



Net gain per acre from poisoning 4. 44 



CORN AS A TRAP CROP. 



Attention has already been called to the fact that corn, when in a 

 suitable condition, is the preferred food of the boUworm, and that 

 cotton is not materially injured until after the corn has begun to 

 harden. It would therefore appear that bollworms might be largely 

 kept out of cotton by the proper use of corn as a trap crop. The use 

 of corn in this way has been frequently recommended by this Division, 

 and instances are not wanting where good results have been secured. 

 Nevertheless, for reasons not apparent, this expedient has been but 

 little adopted. 



Extensive tests of corn as a trap crop in protecting cotton from 

 bollworm injury were made the past year, both at Calvert and at 

 Willspoint, Tex. Unfavorable weather and soil conditions, however, 

 necessitated considerable change in the original plans, and it was pos- 

 sible to have corn in silk for the August generation only. But it is 

 usuall}^ this genei'ation that causes the greatest injury to cotton, and 

 the control of which is especially important. It is not permitted, as 

 in the experiments previously reported, to indicate the value of the 

 trap crop in pounds of seed cotton, as it is manifestly impossible to 

 arrange a control plat which would meet the necessary condition of 

 adjacent location to the plat under test, and at the same time be entirely 

 free from the protective influence of the corn. Bollworm moths fly 

 about freely in the cotton fields and would be attracted a considerable 



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