CHRONOLOGICAL STUDY OF INSECT CONTBOL. 



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 geographical 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. Climatic considerations. 



8. How insect 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 CHRONOLOGICAL 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 

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

 merely preliminary. 



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 year has 

 been different, 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 hall weevil, by years. 





Weevil 



stages. 



Preda- 

 tors. 



Para- 

 sites. 



Per cent 



mortality due to— 



YEAR. 



Preda- 

 tors. 



Para- 

 sites. 



All 

 insects. 



1902 



602 



819 



1,005 



1,702 



40,073 



13,602 



29,349 



11,653 



(?) 

 (?) 

 (?) 

 (?) 



10,547 

 2,279 

 3,862 

 1,231 



7 



59 



32 



21 



1,728 



1,121 



2,952 



620 



(?) 



(?) 



26.31 



16.75 



13.15 



10.56 



1.16 

 7.20 

 3.18 

 1.23 

 4.31 

 8.24 

 10.05 

 5.32 



(?) 

 (?) 

 (?) 



1903 



1905, March 



1905 , August 



(?) 

 30 62 



1906 



1907 



24.99 



1908 



23. 20 



1909 



15.88 









98,805 





6,540 





16.61 













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

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

 records will be found on subsequent pages. 



