COTTON IN" WEEVTL-COjSrTROL EXPERIMENTS 41 



The uniformity of yields from plats 5 to 9 are shown by the graphic 

 presentation of row yields, Figure 10. 



ADVERSE CONDITIONS AT GAINESVILLE, FLA. 



A series of successive plantings and a separate late planting similar 

 to the experiments in Texas and South Carolina were also located at 

 Gainesville, Fla., in cooperation with the Agricultural Experiment 

 Station of the University of Florida, but owing to very adverse sea- 

 sonal conditions the comparisons could not be carried out as at the 

 other locations. The soil upon which these plantings were made is 

 of a light sandy character with a subsoil not retentive of water. 

 Owing to the lack of fertility in this soil cotton production is largely 

 dependent upon the use of commercial fertilizers. 



Extremely dry weather through March and April delayed germina- 

 tion and caused poor stands and was followed by excessive rainfall 

 during May and June. From May 15 until July 4, a period of 51 

 days, rainfall was recorded on 44 days, the total precipitation being 

 19.37 inches. Owing to this excessive rainfall the fertilizer was 

 leached from the soil and plant growth was greatly retarded. Even 

 the earliest planted cotton reached a height of only 12 to 18 inches, 

 and the growth of the late-planted cotton was so checked that many 

 plants never reached the fruiting stage. 



Weevils were present in the successive plantings before squares 

 appeared on the plants. Squares appeared on the early plantings 

 during the latter part of May, and on June 6 they were removed 

 from the plants and poison was applied. The method of stripping 

 and poisoning was the same as that used in Texas and South Carolina. 



Records of weevil emergence from hibernation are maintained by 

 the experiment station. An abnormally high percentage of hiber- 

 nated weevils survived the winter of 1922-23, and emergence con- 

 tinued over an unusually long period. Only about 6 per cent of the 

 weevils placed in hibernation cages normally survive the winter. On 

 June 6, when the squares were removed from the plants in the suc- 

 cessive planting test, 22.6 per cent of hibernated weevils had emerged. 

 Emergence continued until July 31, at which time 26.86 per cent of 

 the weevils placed in hibernation cages had emerged. 



As a result of this prolonged period of emergence cotton became 

 reinfested with weevils after the squares had been removed and 

 poison applied. On July 2, however, the average infestation of 

 squares on all cotton planted at the experiment station was only 3.24 

 per cent. This indicated that square removal and poisoning had been 

 effective in delaying the appearance of the new generation of weevils, 

 though the conditions were such that no significant data could be 

 secured. 



SUMMARY 



In the season of 1923 four successive plantings of cotton were made 

 at San Antonio, Tex., Charleston, S. C, and Gainesville, Fla., to 

 compare the growth and fruiting habits of the plants as affected by 

 the time of planting. 



The successive plantings were treated for control of overwintered 

 weevils by removing and destroying early squares, followed by an 

 application of calcium arsenate. At San Antonio a separate late 



