28 



PROSPECTS. 



The investigations of the life history of the weevil that are referred 

 to in detail in the following pages have indicated that the most impor- 

 tant elements in limiting the spread of an insect — namely, winter tem- 

 peratures and parasites — in this case offer no assurance that the pest 

 will soon be checked. For the past ten years, except where local 

 unfavorable conditions have interfered, it has advanced annually a 

 distance of about 50 miles. The insect is undoubtedly changing its 

 habits and adapting itself to climatic conditions in new regions that it 

 is invading. It is undoubtedly true that it has acquired an ability to 

 withstand more severe frosts than occurred in the vicinity of San 

 Antonio in 1895. Except in a few particular regions, however, it 

 does not seem that the continued spread will be as rapid as it has been. 

 The country between Gonzales County and the Ked River is practically 

 a continuous cotton field, and the prevailing winds have undoubtedly 

 favored the northward spread of the insect. Similar conditions will 

 now favor a rapid extension into the Red River Valley in Louisiana, 

 and likewise there seems no doubt that the spread will be rapid in the 

 Yazoo Valley in Mississippi; but in most other situations throughout 

 the belt the cotton fields are smaller and more isolated than is the case 

 in Texas; consequently it is to be supposed that the spread of the pest 

 will be retarded somewhat. 



Basing estimates on a careful study of the distance the boll weevil 

 has traveled each 3 T ear, as well as upon some attention that has been 

 paid to the means whereby it reaches new territory, referred to more 

 in detail hereafter (p. 123), it seems safe to predict that in from fifteen 

 to eighteen years the pest will be found throughout the cotton belt. 

 During the time it has been in Texas there has been no tendency 

 toward dying out, and in south Texas the pest is practically as trou- 

 blesome, except in so far as it is affected by changes in managing the 

 crop, as it was in 1895. In Mexico, where it has existed for a much 

 longer period, it is apparently as plentiful as ever. Careful attention 

 that has been paid to the study of parasites and diseases, as well as 

 temperatures unfavorable to the insect, has failed to reveal any pros- 

 pect that it will ever be much less troublesome than now. There 

 will, nevertheless, be seasons from time to time in which the damage 

 will be much less than normal. Climatic conditions will undoubtedly 

 cause temporary diminution of the numbers of the pest in certain 

 localities. In Texas these conditions have given rise almost every 

 year to the supposition on the part of the planters that the insects 

 have died out. This was especially the case in the region between 

 San Antonio and Beeviile in 1900, and in the vicinity of Corpus 

 Christi in 1903. Both these years followed a series of seasons in 

 which there was much less than the normal rainfall ; consequently not 



