28 PROLTFERATTON IN OONTKOL OF BOLL WEP.'VIL. 



Average percentage oflocki^ In infiich proliferation follows weevil punctures in bolls as shown in 



serernl preceding tables. 



Tabic II. Feodinn; puiicturo>i in bolls. ProlilViatioii I'orniod in 44. S per cent of total locks 



and in 81.3 per cent of locks sutually fed upon. 

 Table IV. King and Sliinc bolls. Piolifcration formed in o4 per cent of total locks and in 



77.4 per cent of locks actually fed upon. 

 Table V. Fertilized and unfertilized bolls, l^roliferation formed in 07.S per cent of total 



locks. 



These figures indicate that proHferation is stimulated by weevil 

 punctures in somewhat more than 55 \)QY cent of all locks in bolls 

 attacked. The figures in regard to feeding punctures onh", show that 

 proliferation results in nearly 80 per cent of the locks thus attacked. 

 It should be noted here that in many cases the proliferation may have 

 been stimulated by secondary causes, such as the entrance of fimgi or 

 by decay starting in the open feeding pimctures. 



INCREASED MORTALITY OF WEEVIL STAGES IH^E TO PROLIFERATION. 



As would naturally be expected, a study of the increase of mortality 

 attributal)le to j^roliferation will show a somewhat greater variation in 

 the figures for various series of observations than has been found in 

 the percentages of instances in which proliferation occurs. Thus for 

 squares there is found a range of from 9 to 31.6 per cent, the general 

 average being only about 13.5 per cent. For bolls the range is not as 

 great as for squares, being only from 7.1 per cent to 15.6 per cent, 

 while the general average increase in mortality in Iwlls was found to be 

 only about 6.3 per cent. This increase is scarcely one-half as great 

 as was the increase found in squares. 



In neither squares nor bolls is the percentage of mortality sufficiently 

 high to appreciably delay the time of maxinmm infestation by the 

 weevil, since, if hibernated weevils survived in their usual numbers, 

 the num})er of weevils developing would be abundantly able to totally 

 infest a field l)y the time the weevils of the third generation had 

 deposited a majority of their eggs. However, the fact that prolifera- 

 tion does evidently increase the mortality in both squares and bolls 

 must be regarded as a very encouraging sign. It indicates clearly one 

 of the most promising lines of investigation in the future development 

 of cotton varieties which, by possessing this quality in a still greater 

 degree and in combination with other desira])le characters, may prove 

 most desirable for culture in the weevil-infested area. So far as our 

 ]:> resent knowledge is concerned, we may say that the mortality of the 

 weevil is more greatly increased ])y only two other natural factors 

 known — (1) by the effect of long-continued dry weather when the 

 sun has direct access to the fallen squares upon the ground, and (2) 

 by the work of a widely distributed species of native ant, Solenopsis 

 gemhiafd Fab. 



