6 



infested cotton had also been ginned. In these cases no infestation 

 has been attributable to the seed so collected. In one case, however, 

 a farmer was known to have collected the seed on a sheet in the way 

 described, and during the present season it was found that the only 

 field on his farm where the weevil is found was that to which he had 

 hauled bulk seed for fertilizer from the same gin at which he had so 

 carefully guarded his cotton seed. One farmer in Calcasieu Parish 

 ginned his cotton partly at an infested and partly at an uninf ested gin. 

 It has been found that the weevils upon his plantation occur only in 

 the fields grown from seed brought from the infested gin. 



In a sparsely settled country, like the western portion of Calcasieu 

 Parish, where the cotton fields are small and the gins consequently 

 located at considerable distances from one another, the weevils have 

 been carried astonishing distances. Prof. H. A. Morgan, secretary 

 of the Louisiana crop pest commission, has furnished the writer with 

 many interesting examples of this. In one case it has been ascertained 

 that a farmer in the neighborhood of Merryville transported the pest 

 for 16 miles, thus establishing an isolated infestation. That the 

 occurrence of the pest in this locality was not due to its being blown 

 by the wind is demonstrated by the fact that no other cotton fields in 

 the neighborhood are infested, the neighbors having ginned their 

 cotton outside of the infested territory. 



In Shelby County, Tex., a dozen farmers procured seed of a desira- 

 ble varietj^ of cotton, which, though grown in the immediate unin- 

 fested locality, had been ginned farther west, where the weevils were 

 very numerous. On the dozen farms upon which this cotton is grow- 

 ing the present season weevils have invariably been found, although 

 surrounding fields planted from seed that was ginned in the immediate 

 neighborhood have been found to be uninfested. 



CONTROL OF BOLL WEEVIL IN SEED BY FUMIGATION. 



As soon as the facility with wnich the boll weevil is disseminated in 

 cotton seed was understood, the Bureau of Entomology devoted con- 

 siderable attention to the possibility of destroying the pest by fumi- 

 gation.^ Only two gases seem to be at all suitable for this purpose. 

 These are carbon bisulphid and hydrocyanic acid gas, the consensus of 

 opinion among entomologists favoring the former as a fumigant for 

 stored grains. Both of these gases have their drawbacks. As against 

 the danger from the inflammable and explosive properties of carbon 

 bisulphid, there is the danger to human life by the careless use of 

 hydrocyanic acid gas. Experiments by Hicks and Dabney, of the 



« Dr. A. W. Morrill and Mr. W. W. Yothera assisted in the fumigation experi- 

 ments. In these experiments, as well as in all the work leading to the present bul- 

 letin, the writer waa very materially aided by his principal assistant, Dr. W. E. Hinds. 



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