346 



Elementary Principles of Agriculture 



conditions are favorable, produce enough weevils to destroy 

 a field of cotton. The adult weevils hibernate in winter 

 in unopened bolls or under any kind of trash that may be 

 available, especially in the leaves of nearby woods. During 

 the following spring, they begin to emerge in considerable 

 numbers after the first few weeks of warm weather. They 

 feed on the tender portions of the young cotton. 



510. By using improved, early, rapid fruiting varieties 

 of cotton, and cultural methods that favor the same re- 

 sults, early planting, wide rows, frequent tillage, gathering 

 fallen squares, and other measures, a fair yield of cotton 

 may be secured in the presence of the weevil. More than 

 thirty species of birds are known to use the boll weevil as 

 food. Ants, parasitic wasps, and flies, birds, snakes, and 

 climatic agencies assist man in his fight to keep this pest 

 under control. Dry summer weather and prolonged cold 

 winters greatly retard the increase of weevils. 



Fig. 217. Day and night position of leaves of cotton plants. No. 1. Expanded in 

 bright sunlight ready to receive full benefit of the sun's rays. No. 2. Night 

 position supposed to be an adaptation to reduce evaporation of moisture and 

 radiation of heat. From photographs of same plant from the same position. 



