66 



NATURAL CONTROL OF THE COTTON BOLL WEEVIL. 



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

 Louisiana, 1906 — ^Continuod. 





Date. 



Total ex- 

 amined. 



Weevil stages not 

 found. 



Infested by weevil. 



Class of fruit examined, and 

 locality. 



Number 

 of forms. 



Per cent 

 of total 

 exam- 

 ined. 



Numljer. 



Per cent 

 of total. 



Total 

 weevil 

 stages 

 found. 



Hanging bolls: 



Mansfield 



Mansfield 



Many 



Many 



Many 



Aug. 24 

 Sept. 29 

 Aug. 23 

 Aug. 23 

 Aug. 23 



1,412 

 293 



12.T 



800 

 325 



905 

 190 

 74 

 4.50 

 228 



68.3 

 64.8 

 59.2 

 56.3 

 70.2 



447 

 103 



51 

 350 



97 



31.7 

 35.2 

 40.8 

 43.7 

 29.8 



479 

 145 

 54 

 380 

 105 



Totals, hanging l)olls 



2,955 



1,907 



64.2 



1,048 



35.8 



l,lti3 





Aug- 24 

 Sept. 29 

 Aug. 23 

 Aug. 23 

 Aug. 23 





Hanging squares: 



Mansfield 



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 



Many 



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 sho^\*ll 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 

 changing 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 stage.^ 

 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 foimd. In squares, therefore, 

 there were about 1.004 stages 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 contam 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 realty escaped all form of weevil injur}^, it is equally prob- 

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

 found to contam 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 by 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 T(\xas 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. 



