CONTROL OF BOLL WEEVIL IN MISSISSIPPI DELTA. 51 



as from 25 to 50 per cent of the forms which were collected in the 

 bags proved to be uninfested. Of course, a certain percentage of 

 these were uninsured forms which would shed normally, but a con- 

 siderable number undoubtedly were good forms which were broken 

 off by the shaking process. 



The comparison of the two varieties of cotton was not sufficiently 

 complete to allow any general- conclusions, but the most important 

 point seems to be that the bag-and-hoop collects a higher proportion 

 of the infested squares on the long-staple variety than on the short. 



The failure of the mechanical picker to give satisfactory results is 

 very discouraging, as such a picker seems the only solution of the 

 labor problem involved in the collection of weevils and squares. As 

 has been mentioned, the picker tested was the most promising which 

 had come under the observation of the writers, but proved to miss a 

 sufficient number of weevils practically to prevent any reduction in 

 the infestation. In addition, this picker was so injurious to the 

 plants that it actually reduced the crop considerably. 



The information secured on the interplat movement of the weevils 

 in the various field experiments is of considerable importance in the 

 interpretation of the results of such tests. It is seen that in each 

 case there was a more or less increased infestation in the picked rows 

 immediately adjoining the unpicked cotton. However, this was 

 usually slight and extended only a short distance, so it was certainly 

 not sufficient to prevent the control measures from producing a 

 beneficial effect in the treated plats, if they would do so under field 

 conditions. This conclusion is borne out by the fact that identical 

 tests where the control measure tested proved effective have shown 

 a quite definite control reaction within these comparatively small 

 plats. It is probable that the small size of the plats would some- 

 what reduce the extent of the gain in production from any beneficial 

 treatment owing to the immigration of the weevils from unpicked 

 cotton late in the season, but it seems fair to assume that when 

 applying these results to field conditions this factor would be at the 

 very least counterbalanced by the greater thoroughness of the pick- 

 ing operations in these plat tests. It should be remembered that a 

 limited number of pickers were used in all of these plat tests and that 

 they were under the constant supervision of one or more of the ento- 

 mologists. As a result, the operations were conducted far more 

 thoroughly than would be possible under field conditions. 



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