﻿20 BULLETIN 1374, U. S. DEPARTMENT OP AGRICULTURE 



As will be noted, none of the check samples were entirely free 

 from pink boUworm damage, the average percentage reduction in 

 weight of seed of these samples being 0.83 of 1 per cent. This was 

 due to the difficulty of determining from outside appearances that 

 locks of cotton actually contained seed that had been damaged by 

 the pink boUworm. The average percentage reduction in weight 

 of the seed (4.7 per cent) would appear rather low. This was to be 

 expected, however, as all the samples were of the first and only 

 picking in the fields from which they were taken, no second crop of 

 any consequence having been produced in these fields. This fact 

 should also be taken into consideration in connection with the data 

 on damage to the lint. 



DAMAGE TO LINT 



In Table 16 are given the results of tests of the lint samples sub- 

 mitted to the Bureau of Markets, 



The first four headings under ''Lint" come under ''quality," 

 whereas the "percentage of lint" shows the effect of the pink boll- 

 worm on the quantity of lint. There is more difference in the case 

 of the unirrigated than in the irrigated cotton. The 1.7 per cent dif- 

 ference, however, is not the entire reduction in quantity of lint. It 

 is based on the actual weight of the seed, and this had been reduced 

 by the pink boUworm. Comparing with the calculated production 

 of lint in the check samples, there is a reduction of the quantity of 

 lint in the samples of average pick of 5.9 per cent. As in the case of 

 the seed samples, however, the lint samples were possibly too small 

 to be considered as accurately giving the lint turnout. This is indi- 

 cated by the rather wide variations found in some of the samples. 

 The averages given must therefore be considered only as approxi- 

 mations. 



NONPICKABLE COTTON 



In the foregoing discussion "nonpickable cotton" was referred to' as 

 representing part of the total damage done by the pink boUworm to 

 the crop of boUs that actuaUy reach maturity. Nonpickable cotton 

 (fig. 8) is the open cotton left in the fields after the crop has been 

 harvested on account of being too severely damaged by the pink 

 boUworm to be picked. It is expressed as a percentage of the total 

 crop matured and can be determined fairly accurately. In deter- 

 mining the percentage of nonpickable cotton, several representative 

 points were selected in each field, and in 1921 counts were made of 

 all bolls, both picked and unpicked, on a certain number of plants 

 and the number of unpicked locks in these bolls, and in 1922 counts 

 were made of a certain number of bolls both picked and unpicked on 

 consecutive plants and the number of unpicked locks in these. The 

 total bolls and the unpicked locks were then reduced to the same 

 basis, using for the number of locks per boll a figure either arbitrarily 

 set or determined by actual boll examinations in the fields in which 

 counts were made. (In 1921 the first method was followed, the 

 figure used being 4.5 locks per boll; in 1922, using the second method, 

 an average of 4.43 locks per boll was obtained.) From these figures 

 the percentage represented by the unpicked locks is calculated. 



In Table 17 are given the percentages of nonpickable cotton sep- 

 arately for the irrigated and unirrigated fields for both 1921 and 

 1922 and for "zoca" (volunteer cotton) for 1922, based on counts 



