COTTON IN WEEVIL-CONTROL EXPERIMENTS 



17 



cotton illustrates the difficulty of obtaining accurate comparisons of 

 productiveness from adjacent plantings of early and late planted 

 cotton when complete weevil control is not obtained. 



WEEVIL DAMAGE TO BOLLS 



Records of the extent of weevil injury to bolls in the different 

 plantings were made on four dates during the period of boll opening. 

 These records were obtained from the same 50-foot sections of rows 

 which were used in comparisons of flowering and boll shedding. The 

 weevil damage was determined by counting the number of injured 

 and uninjured locks in each of the bolls that had opened in the 

 intervals between the four dates when the records were made. This 

 afforded a means of comparing the extent of the injury to early and 

 late bolls of the successive plantings. 



Table 11 gives the number of bolls picked, the number showing 

 weevil damage, the total number of locks, and the number and 

 percentage of locks damaged by the weevils. The records from the 

 tour 50-foot sections of the first three plantings are summarized and 

 presented in a single unit corresponding to a 200-foot row. 



Table 11. — Extent of weevil injury to bolls in successive plantings of cotton at San 



Antonio 



Date planted, 1923 



Date 

 picked 



Number 

 of bolls 

 picked 



Number 

 of bolls 



by 

 weevils 



Total 

 number 

 of locks 



Locks damaged by 

 weevils 



Number Per cent 



Apr. 19 



Total. 



Apr. 28 



Total. 



May 5 



Total. 



May 12 



Total. 



Aug. 14 

 Aug. 18 

 Aug. 30 

 Sept. 10 



Aug. 14 

 Aug. 18 

 Aug. 30 

 Sept. 10 



Aug. 14 

 Aug. 18 

 Aug. 30 

 Sept. 10 



/Aug. 30 

 \Sept. 10 



243 

 312 

 403 

 101 



1,059 



161 

 215 

 519 

 138 



1,033 



105 

 216 

 521 

 198 



1,040 



300 

 86 



56 

 57 

 175 

 72 



1,061 



1,390 



1,733 



432 



4,616 



52 

 52 

 249 

 105 



719 



968 



2,258 



584 



4,529 



25 

 31 

 313 



129 



472 



968 



2,387 



4,676 



192 



1,410 

 375 



366 

 163 



66 



69 



521 



239 



895 



35 



52 



656 



299 



1,042 



433 

 173 



606 



8.7 



6.4 



21.1 



37.7 



15.4 



9.2 



7.1 



23.1 



40.9 



19.8 



7.4 

 5.4 

 27.5 

 35.2 



22.3 



30.7 

 46.1 



The maturation period of Lone Star bolls in Texas has been shown 

 to be about 42 days/ so that bolls open before August 18 must have 

 developed from flowers appearing prior to July 8. The small amount 

 of weevil injury to these early bolls is due to the slight weevil in- 

 festation during the first part of the flowering stage of the plants 

 and also to the presence of squares. While squares are available 



* Martin, H. D., W. W. Ballard, and D. M. Simpson. Growth of fruiting parts in cotton plants. In 

 Jour. Agr. Research, v. 26, p. 204. 1923. 



20718°— 25° 3 



