16 



THE MEXICAN COTTON-BOLL WEEVIL. 



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

 tabulated below: 



Tab] i XI Relativt attractiveness of various cottons to the boll weevil. 





Num- 

 ber of 



plant-. 





Average. 





of cotton. 



Plant 



Wee- In- 

 vils 



found, square?. 



Weevils 



per plain 

 per day. 



Ixuested 

 squares 

 per wee- 

 vil. 



Kt'lative 

 attrac- 

 tiveness. 



1903. 



- 



4.920 



287 



3.507 



0.058 



12.2+ 



1.0 









5 



8 

 8 



120 

 552 



808 



11 



64 



207 



136 



1.089 

 2,013 



.092- 

 .116- 



12.4- 



17.0+ 

 9.7+ 



1.6+ 





2.0 





4.4 + 







Total of 3 non-American cottons. . 



21 



1.480 



282 



3.23S 



.191- 



11.5- 



3.3- 



1904. 



60 



5 

 4 



3,780 

 315 

 252 



346 

 117 

 102 





.0914 

 .371+ 

 .405- 





l.n 







4.0 







4.4 + 









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 Afifi) 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 Egyptian 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 



Eer cent ^[ Egyptian squares were infested, while an average of 13 

 ("Ids of American showed 75.5 per cent. At Calvert, Tex., on Sep- 

 tember 1. 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 Ami, Janovitch, and Ashmouni) were tested side 

 by Bide 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 \ ariety of col ton 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. \Y. Morrill, by placing squares of two kinds 

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



