THE BOLL-WEEVIL PROBLEM. 19 



fourth of a bale per acre over the crop on the check area where such 

 work was not done. Computmg the increase in the crop at the cur- 

 rent prices, the advantage from the work in the experiment amounted 

 to $14.56 per acre. This was about 29 times the cost of uprooting 

 and burning the plants, as shown by the amount actually paid by 

 the department for the work. Circumstances surrounding the ex- 

 periment show that the advantage was probably considerably greater 

 than has been indicated here. At any rate, the estimate given is 

 most conservative. In this instance the cotton destroyed was 

 isolated, and the results are perhaps somewhat more conspicuous 

 than would have been the case where there were hundreds of cotton 

 fields in the neighborhood. Nevertheless, experience with fields sur- 

 rounded by others that have been given no attention has showTi a 

 great advantage from taking the proper step in the fall. Of course, 

 concerted action will add to the effectiveness of the work and should 

 be followed in every community. 



In addition to the field work by the Bureau of Entomology and 

 by many practical planters, a great deal of work has been done in 

 large cages, where the conditions could be studied most carefuUy. In 

 this way the exact relative advantage of fall destruction at different 

 dates has been determined. It has been shown in this comiection that 

 the earlier the work can be done the better the results wiU be. For 

 instance, seven times as many weevils survived the removal of the 

 infested plants on November 12 as survived after similar work on 

 October 13. 



Mr. J. D. Mitchell, of the Bureau of Entomology, calls attention 

 to a strikmg example of the value of the f aU destruction of the weevils 

 that came to his notice in Texas. On opposite sides of the Guada- 

 loupe River, near Victoria, were two farmers, each having about 40 

 acres in cotton. In one case the stalks were uprooted and burned 

 in September, and in the other they were allowed to stand until 

 shortly before planting time the followmg spring. They were equally 

 good farmers, and the soil was the same on the two places. In the 

 first case the crop was 15 bales, and in the other 3 J bales. The work 

 done during the preceding fall plainly increased the crop about 

 fivefold. 



No definite rule can be laid down as to the proper time for de- 

 stroying the weevils upon and in the fruit of the plants in the fall. 

 In general, the proper time is whenever the weevils have reached 

 such numbers as to infest practically aU of the squares that are 

 being set. This may occur a month or more earlier in some seasons 

 than in others. Fall destruction as late as November wiU accomphsh 

 much, but several times the number of weevils can be destroyed if 

 the work be done in October. Therefore, the rule should be to de- 

 stroy the infested plants at the earliest possible date in the fall. It is 



