66 



NATURAL CONTROL OF TIFF. COTTON IJOLL YVKKVIL. 



Table XV. — Proportion of fruit destroyed by insect injury or by natural causes, 

 Louisiana, 1906 — Continued. 





Date. 



Total ex- 

 amined. 



Weevil stages qo1 

 found. 



Infested by weevil. 



Class of fruit examined, and 

 locality. 



Number 



of forms. 



Per cent 

 of total 



exam- 

 ined. 



Number. 



Per cent 



of total. 



Total 



weevil 



stages 



found. 



Hanging bolls: 



Aug. 24 



Sept. 29 

 Aug. 23 

 Aug. 23 

 Aug. 23 



1,412 



•293 



125 



800 



325 



965 



190 

 74 



450 

 228 



68.3 

 64.8 

 59.2 

 56. 3 

 70.2 



447 

 103 



51 

 3.50 



97 



31.7 

 35.2 

 40.8 

 43. 7 



29.8 



479 





145 





54 



Many 







105 









2,955 



1,907 



64.2 



1,048 



35.8 



1 163 





Aug. 24 

 Sept. 29 

 Aug. 23 

 Aug. 23 

 Aug. 23 





Hanging squares: 



430 



5 



115 



466 



252 



186 

 3 



27 

 136 



69 



43.3 

 60.0 

 23. 5 

 29.2 



27.4 



244 



2 



88 



330 



183 



56. 7 

 40.0 

 76.5 



70.8 

 72. 6 



244 



Mansfield 



2 



Many 



88 





330 





183 







Totals, hanging squares . 



1,268 



421 



33.2 



847 



66.8 



847 







Totals, all forms 



10, 999 



6,154 



56.0 



4,845 



44.0 



5,017 







As is shown in the last line of totals, giving the average percentages 

 for the four classes of forms examined, 56 per cent of the 11,000 forms 

 contained no stage of the weevil. Among 5,561 bolls, including both 

 hanging and fallen bolls, 71 per cent contained no weevil stage, while 

 in the remaining 29 per cent, 1,604 bolls, there were 1,762 weevil 

 stages. This means that in the bolls found to contain weevil stages 

 there were an average of 1.098 stages per boll. Among the 5,438 

 squares, 40 per cent contained no weevil stage. In the 3,241 squares 

 containing stages there were 3,255 found. In squares, therefore, 

 there were about 1.004 stages v for each square. This shows how 

 strictly the multiplication of the weevil is limited by the available 

 supply of squares. An average of squares and bolls shows but 1.035 

 weevil stages for each form which was found to contain them. Among 

 all bolls but 30 per cent contained a weevil stage, while among all 

 squares 60 per cent were infested. While it is probable that few of 

 the 30 per cent of squares which failed to show some stage of the 

 weevil had really escaped all form of weevil injury, it is equally prob- 

 able that a very small portion of the 70 per cent of bolls which were 

 found to contain no stage of the weevil had ever been attacked in any 

 way. Thus, while few squares perished regardless of weevil attack, 

 probably more than one-half of all the small bolls which perished had 

 not been attacked in any way hj the weevil, though it is possible that 

 in many cases there had been some form of injury to the square or 

 bloom connected with that boll. 



In the examination of material from Texas there are so many local- 

 ities represented for each class of forms that it seems advisable to 

 divide the table into a section for each class. 



