46 



THE MEXICAN COTTON-BOLL WEEVIL. 



each class of cotton. The results of this series of experiments are 

 tabulated below: 



Table XI. — Relative attractiveness of various cottons to the boll weevil. 



An examination of Table XI shows that American Upland cotton 

 is less subject to attack by the weevil than any of the others, and that 

 Egyptian (Mit Afiji) is by far the most susceptible. The weevils 

 gathered so thickly on the Egyptian cotton that the plants could not 

 produce sufficient squares to keep ahead of the injury, and therefore 

 the average number of squares for each weevil is only three-fourths 

 as great with that variety as with the less-infested kinds, but the 

 average injury to each square was greater than with any other. It 

 is possible that the greater amount of nectar secreted by the Egyptian 

 cotton plants is responsible for this increased attraction of the weevils. 



The results are still further sustained by observations upon larger 

 areas of American and Eg}^ptian cotton under field conditions in three 

 localities in Texas, no weevils being removed from either kind. At 

 Victoria, Tex., on August 26, 1903, an examination showed that 96 

 per cent of Egyptian squares were infested, while an average of 13 

 fields of American showed 75.5 per cent. At Calvert, Tex., on Sep- 

 tember 4, Egyptian showed 100 per cent infested, while the American 

 varieties growing alongside showed 91 per cent. Similar results were 

 found at San Antonio. Though growing in close proximity, the Egyp- 

 tian produced no staple whatever, while the American gave better 

 than an average yield in spite of the depredations of the weevil. 



At Victoria, in the experimental tract during 1904, three varieties of 

 Egyptian cotton (Mit Afifi, Janovitch, and Ashmouni) were tested side 

 by side with American varieties. The Egyptian varieties uniformly 

 failed to make a pound of cotton, while the American varieties aver- 

 aged 400 pounds per acre. 



In accordance with these observations, it appears that in developing 

 a variety of cotton which shall be less susceptible to weevil attack, by 

 far the most promising field for work lies among the American varie- 

 ties, and of these the very early maturing kinds are most promising. 



The question of choice of different varieties for food was tested in 

 the laboratory by Dr. A. W. Morrill, by placing squares of two kinds 

 of cotton, American and Egyptian, in alternate rows in a rearing cage 



