B. T. I.— 180. 



WEEVIL-RESISTING ADAPTATIONS OF THE 

 COTTON PLANT. 



INTRODUCTION. 



The fact that Central American varieties of cotton have developed 

 weevil-resisting adaptations has already received preliminary notice. 

 A third visit to Guatemala, in the spring of 1905, has given opportu- 

 nity for further studies of the protective characters of the native 

 varieties and for comparing them with the types of cotton now cul- 

 tivated in the United States. For this purpose plantings of Upland 

 and Sea Island varieties have been made in Guatemala, and as the 

 season advanced other tests of the Guatemalan and United States 

 varieties were arranged under very different climatic conditions in 

 Texas and at Washington. 



These opportunities of comparative observation have revealed a 

 series of protective adaptations of such number and nicety as to fur- 

 nish a unique and well-nigh incredible instance of selective develop- 

 ment. The statement of the former paper may be repeated with 

 emphasis, that the presence of the weevil-eating kelep has enabled 

 the Indians of eastern Guatemala to maintain since very ancient 

 times field culture of cotton in the presence of the weevils, with the 

 result that there has been cleA^eloped a dwarf, annual, short-season 

 variety with numerous features which, in the absence of sufficient 

 numbers of keleps, afford material assistance in protecting the crop 

 against the ravages of the weevil. 



Whether this Guatemalan cotton can be made of direct use in the 

 United States or not, it demonstrates the existence in the cotton 

 plant of weevil-resisting characters. The new variety has lint of 

 good length and quality, so that its utilization in the United States 

 depends upon its adaptability to our climate and methods of culture. 



As already explained in publications devoted to the kelep, the 

 weevil-eating propensities of that insect were discovered in 1904 

 during a visit to Guatemala which had been undertaken in the hope 

 of finding a weevil-resisting variety of cotton. It had been observed 



a Cotton Culture in Guatemala. Yearbook of the United States Department of 

 Agriculture for 1904, 475-488; Science, N. S., 20 : 6G6-G70, November 18, 1904. 



