4 BULLETIN 926, U. S. DEPARTMENT OF AGRICULTUKE. 



METHODS USED IN THE STUDY OF THE BIOLOGY OF THE BOLL 

 WEEVIL UNDER FIELD CONDITIONS. 



Large 16-mesh galvanized-wire screen cages 3 by 3 by 4 feet high 

 were used in conducting the field biological studies of the weevil. 

 The cotton plants used in the breeding work were first examined 

 carefully to make certain that no infested squares were present. 

 The large cages were then placed over the plants and a male and a 



S. * C A R O L I N A 



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Fig. 1. — Map of the sea-island cotton area of the United States showing distribution 

 by counties. Each dot represents an average production of 500 bales. (From Orton, 

 Bur. Plant Industry, U. S. D. A.) 



female boll weevil liberated in each cage. On the following day all 

 squares found with egg punctures were recorded, each infested square 

 bearing a light string tag showing the number of the weevil and the 

 date of the egg puncture. After the squares were examined and 

 tagged the cage and weevil were removed to a noninfested plant and 

 the process repeated. Daily observations were made on the plants 

 bearing the tagged squares and the date the infested square dropped 

 off the plant was recorded on the tag. As soon as the infested 

 squares dropped off the plants they were placed in a field hatchery 



