CONTROL lU' WINTKK l•M^rA'|■l(' CONDITIONS. 19 



the sj)riii^, cNorv ])hinl of it sliould IxMlcstroycd to prcx cut itsnourish- 

 in<z; tho wcM'vils Avhich may have survived. The practice of allowing 

 sprout cotton to j^row in a iicld of j)lant cd cotton can not he too 

 stron»z;ly cond(Mun(ML ('(M'tainly if j)hint(M-s could appreciate the fact 

 that tlu»s(^ occasional ])lants will, under usual conditions, enahle the 

 weevils to do nuich ^ri^ater injury to the main cro)), they would Ix^ veiy 

 can^ful to destroy th(Mn. If plantei's in southein Texas fully appre- 

 ciated tlu^ importance^ of this nuMiace, there would soon l)e (levelo[)e(l 

 a stronir puhlic sentinuMit which would compel every ])lanter to adopt 

 nuMhods which would prevent the occurrence of sprout cotton. It 

 is entirely })ossil)le in a prat majorit}^ of ca^cs for the planter to 

 insure for himself the heneiicial effect of a hirge reduction in the 

 numlxn- of weevils surviving hibernation, such as would result from 

 occasional winters of unusual severity, even during seasons which 

 would he favorable for the survival of large numbers of weevils. 

 This, then, is the ])art of cidtural practice which may be made to 

 regularly supj)lement or possibly supplant the beneficial effects 

 which are occasionally experienced by an exceptionally large degree 

 of natural control through severe climatic conditions during the 

 winter. 



RELATIONSHIP OF FACTORS OF CONTROL. 



It is evident that these factors, which are but the extreme fluc- 

 tuations in climatic conditions, will only occasionally exert their 

 maximum efTect, and that under normal conditions of temperature 

 and humidity other factors, having a more constant average effi- 

 ciency, may surpass climatic variations in their controlling effect 

 upon the weevil. It is to a study of some of these average factors 

 that the present paper will be mainly devoted. Among the factors 

 concerned in the natural control of the boll weevil in the United States 

 to which especial attention has been given may be mentioned heat 

 or drying, native ants, proliferation, parasites, the limitation of the 

 weevil's food supply by the work of the cotton leaf -worm (Alabama 

 argillacea Hbn.), and birds. 



In this bulletin special consideration will be given to the effects of 

 heat or drying, native ants, and parasites. Proliferation" was 



« "Proliferation," as the tenn is used in connection with cotton, refers to a phe- 

 nomenon which frequently follows the attack of weevils or other insects in cotton 

 squares and l>olls. It may be defined as the develoj^ment of numerous elementary 

 cells from ]>arts of the 1)ud or boll which are themselves normally the ultimate prod- 

 ucts of combinations of much more highly specialized cells. The resulting j)roduct is 

 thus composed of comparatively large, thin-walled cells, which are placed so loosely 

 together that the formation is of soft texture and has a granular appearance which 

 may be seen with the naked eye. Proliferous formations lack tin; distinctive texture 

 which is characteristic of the normal parts of either bud or l)oll. The consistency of 

 the formation is soft and yielding, resembling somewhat a rather soft g'elatin. From 

 this apparent resemblance the term "gelatinization" is sometimes used instead of 

 jirolifcration. 



