22 



INSECT ENEMIES OF THE BOLL WEEVIL. 



difficulty of giving any single recommendation for the control of the 

 boll weevil which would apply to all regions. This ])oint will be 

 brought out more fuDy in other sections of this bulletin. 



5. A STUDY OF THE SHARE OF INSECT CONTROL IN THE MORTALITY OF 

 IMMATURE BOLL WEEVILS. 



The condensed tables which have been presented are likely to give 

 the impression that the parasite control of the weevil is on an average 

 very low, but it must be remembered that the examinations have 

 been made in all parts of the infested region whether tlie weevil has 

 been present 17 years or only a few months, and whether the \veevil 

 damage amounts to less than 1 per cent of the crop or to almost 100 



Fig. 3.— Diagram illustrating the average climatic and Insect control of the immature boll weevils 

 during 190G, 1907, 1908, and 1909, in fallen squares. (Original.) 



per cent. This great difference in the sources of the material exam- 

 ined has necessarily lowered the average mortality to its minimum. 

 The following records show some of the cases of very high mortality 

 due to parasites: 



Highest records of parasitism of the boll weevil. 

 IN FALLEN SQUARES. 



Locality. 



Date. 



Number 

 of stages. 



Percent- 

 age of 

 parasit- 

 ism. 



Robson, La 



Corpus Christi, Tex 



Natchez, Miss 



Dallas, Tex 



Goliad, Tex 



Natchez, Miss 



Cuero, Tex 



Natchez, Miss 



Shreveport, La 



Victoria, Tox 



Roosevelt, Tex 



Arlington, Tex 



Bro-wnsville, Tex. . . 



Denison. Tex 



Atoka, Okla 



Nov. 5, 1907. 

 June 20, 1907 

 Oct. 23, 1908. 

 Aug. 12, 1908 

 July 28, 1908. 

 Oct. 16, 1908. 

 Aug. 12, 1907 

 July, 1909... 

 Oct. 29, 1908. 

 June 19, 1908 

 Sept. 24, 1901) 

 July 17, 190S. 

 Sept. 5, 1906. 

 July, 1909... 

 Sept. 2, 1908. 



S3 



92 

 157 



18 

 114 

 230 

 105 

 200 

 624 

 513 



69 

 382 

 ,147 

 494 

 100 



77.36 

 36.95 

 28.6 

 27.78 

 26.63 

 21.7 

 19.04 

 18.5 

 15.8 

 14.5 

 14.4 

 13.35 

 12.4 

 8.5 

 8.0 



