100 



Among the first group we mention in the first place cli- 

 matic control. The factors of highest importance in de- 

 termining the development, distribution and destructive- 

 ness of the boll weevil are temperature, preci- 

 pitation and food suppl^^ We have stated that the wee- 

 vil has but a single food plant — the cotton — and it is 

 remarkable how thoroughly adjusted to the condition 

 of the food plant the weevil has become. Conditions 

 favoring the growth of the cotton plant are also favor- 

 able to the development of the weevil. 



High temperatures and abundant rainfall are the two 

 climatic factors distinctly favorable to weevil develop- 

 ment, and hence it is that at such times their injury is 

 most noticeable. Rains tend to increase formation of 

 squares by the cotton plant and the squares, we have 

 seen, are the feeding places and oviposition structures 

 for the weevils. Rains also indirectly favor weevil de- 

 velopment by the injury they do to the natural enemies 

 of the weevil. 



Too heavy rains during the winter are very apt, to kill 

 many of the hibernating weevils and hence following a 

 comparatively dry winter one would expect to sec a 

 larger brood of hibernated adult weevils appear U\ the 

 spring than following a rainy winter. 



Experiments have shown that overflows will not in- 

 jure enough weevils to be of any great service. Even the 

 larvae and pupae in eqtiares that have been under Y\ater 

 for some time were found to be uninjured. Adult Avee- 

 vils may float several days in the water and yet not be 

 injured. It is very probable that the floating of adtilt 

 and infested squares by means of high water will prove 

 one of the most important natural agencies for wklely 

 distributing the pest. 



PARASITES^ PREDATORY INSECTS;, AND DISEASES. 



The verv recent announcement bv .an officer oC the 

 United States Department of Agriculture of the di.-^ 'v- 

 ery in Guatemala of an ant that preys upon the boll 

 weevil has called forth renewed interest in this subject 

 of parasites or rather predatory insects. However, 



