28 



INSECT ENEMIES OF THE BOLL WEEVIL. 



Following the plan adopted for the three preceding years these 

 figures may be weighted for comparison with the earlier records: 



Table XIV. — The hypothetical or weighted average mortality of the boll weevil iti I'jOU.^ 



Class of fcrins. 



Hanging bolls 



Hanging squares 



Total hanging. 



Fallen bolls 



Fallen squares 



Total fallen.... 



Totals and aver- 



0.75 

 4.25 



14.25 

 80.75 



75 

 425 



1,425 

 8,075 



9,500 



10,000 



1909— Mortality from— 



Prolifer- 

 ation. 



6.30 

 13.50 



6.30 

 13.50 



4.7 

 57.4 



62.1 



90.0 

 1,090.1 



1,180.1 



1,242.2 



70.3 

 367.6 



437.9 



1,335.0 

 6,984.9 



8,319.9 



Climate. 





37.94 

 12.96 



27.74 

 26.58 



23.01 



26.7 

 47.6 



370.3 



1,856.6 



2, 226. 9 



2, 301. 2 



Predators. 



5.21 

 6.38 



3.7 

 23.4 



15. 00 200. 2 

 12. 39 865. 4 



1,065.6 



10*921,092.7 



Parasites. 



3.52 



19. 49 



2.44 

 2.24 



2.63 



Total. 



C3 C3 



2.5 

 71.6 



32.6 

 156.5 



263.2 



50.13 

 47.29 



37.6 

 200.0 



237.6 



48. 63 693. 1 

 49. 14 3, 968. 6 



4,661.7 



48.99 4,899.3 



1 Given 10,000 weevil stages. 



This table shows a weighted decrease of 3.71 per cent for parasites 

 and a weighted increase of 0.62 per cent for all agencies due to an 

 increase in climatic control. 



In the following table is given a comparison of the weighted aver- 

 age control by all agencies for the four years. 



Table XV. — Weighted average mortality of the boll weevil, lb06-lV0'j. 



In view of the fact that certain cotton varieties retain the infested 

 squares more than others, it is interesting to make another hypothesis 

 on the basis that 50 per cent of the infested forms are hanging. The 

 year 1908 is chosen to illustrate this phase of the subject. 



