UNITED STATES DEPARTMENT OF AGRICULTURE 
; BULLETIN No..926 , 
Contribution from the Bureau of Entomology 
L. O. HOWARD, Chief 
Washington, D. C. PROFESSIONAL PAPER April 19, 1921 
STUDIES IN THE BIOLOGY OF THE MEXICAN COTTON 
BOLL WEEVIL ON SHORT-STAPLE UPLAND, LONG- 
STAPLE UPLAND, AND SEA-ISLAND COTTONS. 
By GerorGeE D. SmitH, Hntomological Assistant. Southern Field-Crop Insect 
Investigations. 
CONTENTS. 
Page. Page: 
AeA CU COM ss = ree at TS PG ee 1 | Length of time upland cotton 
Historically review 22222 ee 2 squares hang on the plants after 
Scope of the present life-history CLS DUM CET Cleese eer ae ey eens 20 
SPUMIeS) etna See ee 3 | Fecundity records of hibernated fe- 
Methods used in the study of the male boll weevils on upland cotton 
Hea aie under outdoor insectary ; under field conditions___________ 21 
RO OS SS SS Summary of the developmental 
Methods used) in’ the study of the period of the first generation boll 
biology of the boll weevil under Ra 
AIG EL he ee 4 weevils in upland cotton squares 
Food plants of the boll weevil____~ Hy) under field conditions WARE Go & arate 22 
The boll weevil on sea-island cotton_ 6 | Developmental period of first genera- 
Longevity of adult boll weevils on tion boll weevils on short-staple 
upland and sea-island cottons___ 7 upland, sea-island, and long-staple 
The size of the cotton square at- upland cottons under field condi- 
tacked by boll weevils_________- 10 tions____-~-_--_-~---_~---~---- 23 
Locations selected for oviposition Comparison of the developmental 
on sea-island and upland cotton period of the immature stages of 
SCWURCS a Saas SE hi Oe ee eee ee aL the boll weevil under field and in- 
Period from emergence to ovi- Sectanys CONdibOnS sass) aera 25 
position_ _____--____-_____~__- - 11 | Developmental period of the boll 
Oviposition period of the boll weevil weevil in green cotton bolls_____ 27 
under insectary conditions______ 11 | Fecundity of the boll weevil in up- 
Summary of the fecundity of the land and sea-island cotton bolls__ 28 
boll weevil on sea-island and up- The relation of temperature to th 
land cottons under insectary con- pas . y raha a 
"SE GSC ETIS) Sates ce age ea 13 biology of the boll weevil Beall Fie 30 
The average developmental period of The developmental period of the boll 
the cotton boll weevil under out- weevil on different types of soil__ 32 
door insectary conditions_______ 14 | The effect of the determinate growth 
The developmental period of the boll of the cotton plant on the biology 
weevil under field conditions____ 15 Ore the sbolivaweevil oes te eae eee 32 
Hgg-laying activity of hibernated Hibernation of the boll weevil in 
female weevils under field con- J SRI Wares (GG) fate, i De pe 33 
CLC VO TS eee eee care LOS |G eneralle Summ arya 43 
INTRODUCTION. 
The studies in the biology of the Mexican cotton boll weevil (An- 
thonomus grandis Boh.) upon which this paper is based were con- 
“The cotton varieties used in these studies were a short-staple upland cotton known 
as King, a long-staple variety known as Webber No. 49, and a sea-island cotton known 
as Hope Straight. 
16073°—21 1 
