CHRONOLOGICAL STUDY OF INSECT CONTROL. 



13 



The matter is arranged topically as follows: 



1. A general chronological study of the insect control of the boll 

 weevil. 



2. The nature and sources of the material examined. 



3. Seasonal studies of the insect control by class of infested material. 



4. A geograpliical study of the statistics. 



5. A study of the share of insect control in the mortality of imma- 

 ture weevils. 



6. A study of how agriculture modifies insect control. 



7. Chmatic considerations. 



8. How msect control follows the weevil dispersion. 



9. The status of the boll weevil and its control by insects. 



10. A brief statement of the various classes of control exercised 

 upon the weevil. 



11. Practical conclusions derived from statistical studies. 



1. A GENERAL CHRC^NOLOGICAL STUDY OF THE INSECT CONTROL OF 



THE BOLL WEEVIL. 



Kecords upon parasitic control of the boll weevil begin in July, 

 1902, and occur more or less scatteringly until June, 1906. The 

 rccorils of 1906 were very extensive, but, as will be shown, they were 

 merely preliminar}^. 



Table I is arranged to show the extent of the examinations made 

 since 1902, This table should not be used to compare the records 

 of the various years, as the manner of investigation in each 3"ear has 

 been cUfferent, and the sources of the material have varied greatly. 

 The table is only intended to show the total of the examinations and 

 how these were distributed from year to year. A careful analysis of 

 the figures has been given in the various sections of Part I. 



Table I. — Insect control of the boll weevil, hy years. 



Weevil 



stages. 



Preda- 

 tors. 



Para- 

 sites. 



Per cent mortality due to — 



Preda- 

 tors. 



Para- 

 sites. 



All 

 insects. 



1902. 

 1903. 



1905, March.. 

 1905, August. 



1900 



1907 



1908 



1909 



Totals and averages. 



602 



819 



1,005 



1,702 



4(1, 073 



13,C02 



29, 349 



11,653 



(?) 

 (?) 

 (?) 

 (?) 



10,547 

 2,279 

 3,802 

 1,231 



7 



59 



32 



21 



1,728 



1,121 



2,952 



C20 



(?) 



(?) 



(?) 



(?) 



26.31 



10.75 



13.15 



10.56 



1.16 

 7.20 

 3.18 

 1.23 

 4.31 

 8.24 

 10.05 

 5.32 



98,805 



6,540 



16.01 



(?) 



(?) 



(?) 



(?) 

 30.62 

 24.99 

 23.20 

 15.88 



1 This table should not be construed as indicating that parasite control has been falling off, because 

 the table is based upon ditlerent kinds of examinations in diflerent years. The detailed analysis of these 

 records will be found on subsequent pages. 



