17 



engaged in an investigation of the weevil in that country, which was 

 begun the preceding year, was continued. Much material, such as 

 parasites, was exchanged, and each investigation was kept informed of 

 the progress of the other. 



In addition to the work in Texas Mr. E. A. Schwarz spent several 

 months of the past year in Cuba, studying the manner in which natural 

 conditions, whether of parasites, diseases, climatic conditions, or of the 

 presence of a degree of resistance on the part of the plant, controlled 

 the insect where it has existed as an enemy of cotton for a much 

 longer period than in the United States. He found what appears to 

 be the original food plant in the "algodon de rinon" or kidney cotton 

 of that island. Nevertheless, he failed to discover any parasites at all, 

 and did not succeed in finding any important tendency toward immu- 

 nity on the part of the live distinct varieties studied. Through the 

 interest and courtesy of Mr. Edward Ferrer, the proprietor of a large 

 estate nearer Ca^^amas, Mr. Schwarz arranged to have several wild 

 varieties planted on land where a seriously infested field had grown 

 the year before. Mr. Ferrer has very recentl}^ reported that none of 

 these varieties have exhibited the slightest tendency toward immu- 

 nit}^, the squares of the native varieties being punctured as freel}^ by 

 the weevils as those of the ordinary American cotton. The experi- 

 ment thus bears out the previously published conclusions of the inves- 

 tigators of the Division of Entomology, based upon observations in 

 Mexico and Central America as well as in Texas, that apparently no 

 known variet}" or strain of cotton is distasteful to the weevil. How- 

 ever, the importance of a continuation of this line of the work is 

 evident. 



SOME OF THE RESULTS OF THE FIELD WORK. 



Upon the plantation of Mr. A. P. Borden, to which reference has 

 already been made, the Division of Entomology had a 100-acre field 

 planted in such a manner as to show the value of several methods of 

 treatment. The experiment was purposely located upon land that had 

 been in cotton for a number of 3^ears, and in a situation adjoining the 

 river, where the weevil damage is generally greatest. As will be seen 

 in the accompan3'ing diagram (fig. 3), the field was divided into four 

 plats of 25 acres each. All the plats were planted with the seed of 

 a typical early maturing variety. Two of these plats were planted as 

 early as possible, and one of these was given more thorough cultiva- 

 tion than the other. The two remaining plats were planted late, and 

 the same difference in cultivation applied. The results were as follows: 



Early King cotton with thorough cultivation produced 459 pounds 

 of lint to the acre. 



Early King cotton with less thorough cultivation produced 250 

 pounds of lint to the acre. 

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17294— No. 189—04 2 



