55 



sons. First, woovils escai)iii,i* iiiiincdialc dcsliiictioii in 

 Held A, whore slalks are destroyed early, ean live at 

 that season of the year for only abont two weeks with- 

 out food. They must therefore fly to the undestroyed 

 eotton of the neighboring field B, to find food or they 

 will starve to death before it l)econies eold enough for 

 them to live without food. The number of weevils 

 hibernating in or around field A, therefore, becomes 

 negligible while that in field B is increased by weevils 

 coming from A. Second, the winter shelter conditions 

 arc most unfavorable for weevils in Held A, and most 

 favorable in field B wdierc stalks are. permitted to- 

 stand- (See page 34). Third, we shall assume that 

 both farmers are likely to plant at about the same time 

 in the spring. Weevils emerging from or around field: 

 B will therefore find food close by and very few will 

 therefore go further to reach field A. This is true- 

 especially because weevils do not fly in the spring near- 

 ly as readily as they do in the fall. 



In a most careful study of this matter, using markecf 

 weevils, a number of individuals were followed in their 

 movements in a cotton field for more than six weeks 

 in the spring. During this time they had not moved 

 more than fifty yards from the point at which they 

 started. Therefore the movement from field to field is 

 slight as a rule so long as uninfested squares continue 

 abundant where the w^eevils occur. 



Communitij Cooperation Best. — No man should de- 

 lay in making the fight because of the lack of co-opera- 

 tion on the part of his neighbors but it is unquestion- 

 ably better for the whole community if general co- 

 operation can be secured as the danger of an early 

 rcinfestation will be correspondingly decreased. 



RRIXCIPAL FACTORS IN NATURAL CONTROL OF 

 THE BOLL WEEVIL. 



Fear Groups of Factors. — There are four principal 

 groups which include the most important of all the 

 natural factors of control affecting the boll weevils. As 

 a result of records made by the agents of the U. S. 

 Bureau of Entomology, from the examination of more 

 than 222,000 squares and bolls collected principally in 

 Texas but representing also conditions in Oklahoma. 

 Louisiana, Arkansas and Mississippi, it appears that 

 these four factors are together responsible for the de- 

 struction of more than half of the weevil stages that 



