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BULLETI]Sr 1374, U. S. DEPAETMENT OF AGEICULTUKE 



The live-steam macMne was found under practical working con- 

 ditions to have a capacity of 5 bushels per minute and required not 

 more than two horsepower. The cost of operation was about the 

 same as in the case of the dry-heat machine. 



Continuous series of germination tests were made during the 

 operation of these machines. There were no indications of any 

 appreciable reduction in the vitality of the seed. 



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Fig. 14.— Number of infested cotton blooms per acre in poisoned and check plats, 1921 experiments, 

 as shown by weekly examinations. First examination made sis days after treatment began 



POISONING EXPERIMENTS 



The habits of the newly hatched pink boUworm larva suggest that 

 there may be an opportunity to kill it by means of poison before 

 it enters the boll or while it is attempting to enter. Experiments 

 were instituted at Tlahualilo to determine whether any degree of 

 control could be attained by dusting with arsenical poisons. 



In 1921, nine separate plats in large cotton fields were treated, 

 seven of these with calcium arsenate and two with arsenite of zinc. 

 Records were kept at the same time on an equal number of check 

 plats of ecjual size. As the purpose of these first experiments was 

 to determine whether any control could be attained, no attempt was 



