1932 - Gaines, J. C. Studies on the progress of boll weevil infestation at various dis- 



tances from hibernation quarters. J. Econ. Ent. 25(6):1 181- 1 187. 



The relation between the progress of infestation by Anthonomus grandis 

 Boh. in cotton at various distances away from the hibernation quarters and the 

 flight of the weevils was determined by a study carried out in Texas in 1930 

 and 1931. The degree of movement from field to field was indicated by traps 

 situated in and between cotton fields. Extensive migration began about 

 September 15th, or just after the maximum number of weevils was caught in 

 heavily infested fields, and when 75% of the squares were punctured. 



In 1931, in order to determine the time taken by weevils to spread various 

 distances from hibernation quarters, traps were placed at intervals varying 

 from 1/8 to 1-1/4 miles from woodland bordering a strip of level land mainly 

 planted to cotton. In both seasons as infestation increased, the accumulative 

 catch on the traps did so, also, to approximately the same degree. 



In 1931, no weevils were caught in the traps set up in March until July 23d. 

 The first infestation was recorded on June 18th in cotton nearest to favorable 

 hibernation quarters, when 3% of the squares were punctured. In 9 weeks the 

 percentage had doubled and the weevils had spread 3/4 mile. About 3 weeks 

 later they had again spread approximately as far again. Weevils were first 

 taken on the traps at 3/4, 1, and 1-1/4 miles on September 4th, 7th, and 11th, 

 respectively. They thus appear to spread in cotton slowly for the first part of 

 the season up to a point when they begin to migrate more rapidly and cover a 

 larger territory. 



The maximum number of weevils was caught on a trap situated on a clear 

 section between hibernation quarters and cotton during the first week in 

 September, when movement in large numbers was taking place from field to field 

 and distribution had become general. At this time weevils were caught at the 

 greatest distances from hibernation quarters. This general migration occurred 

 during a dry season, and may occur earlier in some years than in others. 



The maximum fruiting date in the later planted cotton around the trap 

 situated at the farthest point from hibernation quarters did not occur until the end 

 of August. The abundance of fruit on this cotton was attractive to the weevils 

 after the general migration period had begun, and the numbers caught there after 

 September 11th were greater than on traps nearer the hibernation quarters. 



1933 - Calhoun, P. W. Irregularity among cotton plants in time of fruiting as a factor 



affecting susceptibility to damage by the cotton weevil. J. Econ. Ent. 26(6):1125- 

 1128. 



A considerable variation in the date of fruiting of different cotton plants 

 growing together, whether due to environmental or to varietal differences, would 

 obviously lead to greater damage by Anthonomus grandis Boh. The few early 

 plants would serve as breeding places for weevils that would migrate to the later 

 plants before the bolls on the latter had matured. Of 600 plants observed in a 

 field in Florida, the very earliest blossomed 12 days earlier than the last half. 

 Maximum frequency of blossoming occurred on the 11th day. In an entirely 

 uninfested field, the half of plants that blossomed earlier might be expected to 

 produce more cotton than the last half. However, a large proportion of the plants 

 that actually produce an average number of bolls began to fruit 9 to 10 days later 

 than the earliest 10%. The presence of the very early plants in a heavily infested 

 field would have reduced the crop, rather than increased it. 



1936 - Smith, G. L. Percentage and causes of mortality of boll weevil stages within the 

 squares. J. Econ. Ent. 29(1 ):99- 105. 



The chief factors effecting boll weevil mortality in the immature stages are 

 climate, predators, parasites, and proliferation. Of these, climate is ordinarily 

 the most important in the case of fallen squares, although of relatively small 



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