26 



PROLIFERATION IN CONTROL OF BOLL WEKVIL. 



Increased inoiiaUty in squares without proJiferation accompanyimj increased severity in weevil 



attack. 



VnriPtv. 



King 



Native. . 

 Territory 

 Shine...'. 



Per cent 

 of mor- 

 tality. 



1.6 

 2.7 

 4.9 



11.2 



The comparison given above shows very clearly the great increase 

 in mortality accompanying increased severity in the weevil attack. 

 The data here given furnish a very interesting confirmation of the 

 conclusions stated in Bulletin No. 51 of the Bureau of Entomology 

 (p. 119). The statement most directly confirmed is here repeated. 



By this time the number of weevils has become so great that the supply of squares is 

 insufficient to meet their need for both feeding and oviposition. Selection of scjuares so 

 that these two portions of their attack may be kept separate can no longer be exercised. 

 Female weevils are forced to deposit their eggs in scjuares which have either received other 

 eggs or been largely fed upon, and a much larger proportion of scjuares at this time shows that 

 feeding punctures are made in scjuares having eggs or larvK>. By these two factors the 

 mortality among young larva? especial!}^ is greatly increased. 



An examination of the figures given shows that in Territory cotton 

 were found twice as many weevil stages as in King, and among these 

 there were 6 times as many dead. In Shine cotton having more than 

 twice as many weevil stages as the King, 15 times as many stages were 

 dead. 



INCREASED MORTALITY IN SQUARES AND BOLLS DUE TO 

 PROLIFERATION. 



Next in order will be a special study of the increased mortality in 

 scjuares and bolls which may be attributed directly to the formation of 

 proliferation. The figures for srpiares and bolls together include more 

 than 20,000 observations. In many cases the records are taken from 

 data which have been used in preceding tables. 



