14 



NATURAL CONTROL OF THE COTTON BOLL WEEVIL. 



could multiply so as to do any considerable damage the plants had 

 set a normally good crop of fruit. Wiile weevils became numerous 

 later in the season, a yield of nearly one-fourth of a bale was obtained 

 from this half-acre plat. 



The beneficial effect of this drought during the squaring season 

 in Victoria County may be shown by a comparison of the yields for 

 the seasons 1903 to 1906, inclusive. These figures as given by the 

 Bureau of the Census in equivalent 500-pound bales are as follows: 



Yields of cotton in Victoria County, Tex., 1903-1906. 



Year. Bales. 



1903 ' 5, 355 



1904 6, 495 



1905 9. OIG 



1906 16, 963 



INFLUENCE OF A DRY SEASON UPON SUCCEEDING SEASON. 



The duration of the dry period as related to the growing season of 

 cotton determines primarily whether the beneficial effect shall be 

 prolonged beyond one season. In the case cited at Victoria drought 

 occurred only in the first third of the season, and its effect was upon 

 the immediate crop, but the benefit would not be continued into the 

 following year. In some of the dryer regions of cotton production 

 it is not unusual to have an entire season covered by a period of 

 comparative drought, and under such conditions the effect upon 

 w;eevil abundance is quite different. Several illustrations of this 

 have occurred in the region between Corpus Christi and San Antonio, 

 Tex. One of the most definite instances is here given by way of 

 illustration. In this case the effect was widespread, and may be 

 judged by a comparison of rainfall, temperature, and crop conditions 

 for Nueces County, Tex., during the years 1901-1904. 



Table II. — General illustration of drought control, Nueces County, Tex., 1901-1904. 





Rainfall. 



Temperature. 



Cotton 

 produc- 

 tion, 

 Nueces 





Annual. 



Mar.l-Aug.31. 



Annual. 



Mar.l-Aug.31. 



Year. 



Total. 



Depar- 

 ture 

 from 



normal. 



Total. 



Depar- 

 ture 

 from 

 normal. 



Mean 

 aver- 

 age. 



Depar- 

 ture 

 from 

 normal. 



Mean 

 aver- 

 age. 



Depar- 

 ture 

 from 

 normal. 



County, 

 equiva- 

 lent 500- 

 pound 

 bales. 



1901 



1902 



190.3 



Inches. 

 17.49 

 22.22 

 36.92 

 28.54 



Inches. 

 -11.90 



- 7.98 

 + 6.72 



- 1.66 



Inches. 

 6.74 

 5.57 

 25.97 

 13.56 



Inches. 



- 7.42 



- 7.39 

 + 11.38 

 + 0.83 



70.7 

 71.5 

 69.1 

 70.5 



°F. 



0.0 

 -1- 1.4 

 - 0.9 

 -1- 0:4 



°F. 

 76.2 

 77.3 

 74.5 

 76.0 



°F. 

 0.83 

 -1-1.85 

 - 0.9 



+ 0.5 



601 



480 



4,099 



1904 



1,5.56 



