USE OF RESISTANT PLANTS 



1903 - Webber, H. J, Improvement of cotton by seed selection. U. S. D. A. Ybk for 



1902:384-385. 



Remarks on the relative extent of injury by the boll weevil to several vari- 

 eties of Egyptian cotton. 



1904 - Cook, O. F. Evaluation of weevil - Resistance in cotton. Science 20(5l6):666-670, 



Thoughts on the evolutionary history of the relations between the cotton 

 plant in Guatemala and the boll weevil. Changes in plant characteristics, such 

 as the large leafy involucre, hairiness of stems, gelatinization on young bud 

 tissues, and proliferation as they effect weevil attack are discussed. 



1905 - Hunter, W. D. The control of the boll weevil, including results of recent investi- 



gations. U. S. D. A, Farmers' B. 216, 32 p., 5 fig. 

 An account of a variety test of cotton. 



1906 - Cook, O. F. Weevil resisting adaptations of the cotton plant. U. S. D. A. Bur. 



Plant Ind. B. 88, 87 p. Jan. 13. 



An extensive account of various supposed weevil-resisting characters of 

 cotton. 



1907 - Hinds, W. E. Proliferation as a factor in the natural control of the Mexican 



cotton boll weevil. U. S. D. A. Bur. Ent. B. 59, 45 p., 6 pi. 



In 1902 it was noted that the cotton plant has a tendency to protect itself by 

 proliferation of cells at the point of injury by the cotton boll weevil in the 

 squares or bolls. A thorough study of this phenomenon was carried on and 

 statistics collected bearing on the problem of the effectiveness of this tendency 

 of the plant in controlling the pest. 



In many varieties of American upland cotton, proliferation takes place in 

 51% of the cases of weevil attack upon squares and in 55% of those upon bolls. 

 The increased rate of mortality among weevils as a result of this proliferation 

 was found to be 13.5% in squares and 6.3% in bolls. Climatic conditions appear 

 to have little effect upon proliferation, and all varieties of American upland 

 cotton appear to proliferate to about the same extent. The use of fertilizers 

 apparently does not increase proliferation, and the proliferating tissue is not 

 poisonous to the weevils. The author concludes that the weevil larvae are killed 

 mechanically by pressure from the proliferated cells and not from any toxic 

 properties of those cells. 



1908 - Bennett, R. L. A method of breeding early cotton to escape boll weevil damage. 



U. S. D. A. Farmers' B. 314, 28 p. Feb. 7. 



Describes practical means of improving cottonseed by plant and seed 

 selection. 



1909 - Newell, W., and A. H. Rosenfeld. Report upon variety and fertilizer experiments 



with cotton in the boll weevil infested sections of Louisiana. La, Crop Pest 

 Comn. 26:65-86. 



At Bayou Pierre, 6 cotton varieties were planted March 31 and April 1. On 

 May 11, approximately 58 weevils per acre were found in the plots, and by 

 May 28 the average number of overwintered weevils had increased to 155 per 

 acre. On June 13, 2% of the squares on the plots were infested, as compared 

 with 3.5% to 12% in fields near timber. On July 9, the average number of bolls 

 per plant for the different varieties was as follows: 



Hawkins Early Prolific 17.8 



Improved Peterkin 15.8 



Mehane Triumph 12.4 



Seago 11.4 



Keno 10.9 



"Native" 10.9 



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