COTTON IN WEEVIL-CONTROL EXPERIMENTS 25 
not produce squares until the emergence of weevils from hibernation 
had been completed. Poison applied before the appearance of 
squares in early-planted cotton would be less effective, as late emerg- 
ing weevils would reinfest the field. 
DEVELOPMENT CF PLANTS IN THINNED AND UNTHINNED ROWS 
In order to compare the development of the plants in thinned and 
in unthinned cotton, records of plant height and number of nodes 
on the main stalk, the number of squares produced, and the number 
of internodes on the fruiting branches were obtained on 10 repre- 
sentative plants of each spacing. These records were started on 
June 27 and were taken at biweekly intervals until August 9. 
The average number of internodes on the main stalk and the height 
of plants on June 27 were practically the same on plants which had 
been thinned to two in a hill on June 15 and on plants left unthinned. 
Those in both spacings averaged 11.1 nodes on this date, while the 
height averaged 28.8 centimeters for unthinned and 28.9 centi- 
meters for the thinned plants. 
The number of internodes on plants of both spacings remained 
practically equal throughout the period during which data were 
obtained. The final records, obtained on August 9, showed that the 
unthinned plants averaged 17.2 internodes, while the thinned plants 
averaged 18 internodes on the main stalk. The thinned plants had 
grown to a slightly greater size, however, their height averaging 
67.3 centimeters, as compared with 63.2 centimeters on those un- 
thinned. It is apparent that different plant spacings had a negli- 
gible effect on the development of internodes of the main stalk and 
on the height of the plants. The dry weather at San Antonio during 
this season retarded the development of all plants, and it is possible 
that greater differences in the size of plants would have resulted if 
more moisture had been available. 
Although the development of the main stalk was the same on 
thinned and unthinned plants in this test, the thinned plants had a 
larger number of internodes formed on the fruiting branches, as 
shown by records obtained on August 9, when the growth of all 
plants had practically stopped. These data, showing the compara- 
tive nodal development of groups of fruiting branches on thinned 
and unthinned plants: are presented in Table 14. The thinned 
plants had a consistently larger number of internodes on each group 
of fruiting branches than the unthinned plants. 
TaBLEe 14.—Number of squares on plants and average number of internodes on 
fruiting branches of thinned and unthinned plants in a late-planting test of cotton 
at San Antonio in 1923 
Average number of internodes 
on fruiting branches on 
August 9 
Total number of squares on plants at 
2-week periods 
Plant spacing 
Branches Branches | Branches 
June 27 | July 12 | July 25 | August 9 1to4 5 to 8 9 to 12 
