28 BULLETIN 918, U. S. DEPARTMENT OF AGRICULTURE. 



Loss in the Quality op Lint. 



The 2-pound gin samples were sent to the United States Bureau 

 of Markets for examination. Mr. George Livingston, Chief of 

 Bureau, reported in letter dated April 13, 1920, as follows: 



In a general way it may be stated that all of the samples were of very poor quality, 

 especially as regards length and strength of staple. The results obtained through 

 the ordinary commercial classification of cotton were confirmed by individual fiber 

 strength tests which produced subnormal results. It is commonly considered that 

 upland cotton should show an average strength for individual fibers of about 8 

 grams, but none of the Mexican samples possessed that degree of strength. Several 

 of the samples were so weak that a considerable portion of the fibers broke upon being 

 inserted in the jaws of the testing machine. Such cotton is so weak in staple as to be 

 practically unspinnable. 



The exact degree of the deterioration in the quality of lint men- 

 tioned above which is due to the pink bollworm can not be definitely 

 stated, but undoubtedly a certain percentage of it is caused by mal- 

 nutrition of the seed, which arrests the development of the lint. 

 Ballou (11, p. 265) states: 



In addition to the actual damage done to the lint and seed of the attacked seed, 

 there is the injury which results to sound seed in attacked bolls. This appears to be 

 a matter of malnutrition, the attacked seed making demands on the supply of the 

 plant food to such an extent that nearly all the seeds in the boll are deprived of a 

 portion of their nutriment. 



Loss in Weight of Seed. 



As the amount of seed destroyed or practically destroyed by 



P. gossypiella was found to assume proportions worthy of consider-. 



able notice, an attempt was made to ascertain the exact loss by 



weight caused in this manner. From material picked during the 



year, samples of seed cotton were accurately weighed, hand-ginned, 



and the seed examined individually and weighed, with the following 



results : 



Table XIII. — Loss by weight to sad -when hand ginned. 





Weight 



of 

 sample. 



Total 

 num- 

 ber 

 seed. 



Sound seed. 



Damaged seed. 



Lint. 



Sample. 



Num- 

 ber of 

 seed. 



Weight 



in 

 grams. 



Aver- 

 age 



weight 

 per 



seed in 



gram. 



Num- 

 ber of 

 seed. 



Weight 



in 

 grams. 



Aver- 

 age 



weight 

 per 



seed in 



gram. 



Loss in 

 weight 



per 

 seed in 

 gram. 



Weight 



in 

 grams. 



Per 

 cent. 



First pick, Zara- 

 gosa. 



Second pick, 

 Zaragosa. 



Third pick, San 

 Isidera. 



458 gms. 



(lib.) 



...do.... 



...do.... 



2,438 

 2,855 

 3,678 



2,282 

 2,388 

 1,753 



252.65 

 244.38 

 180.20 



0.1107 

 .1023 

 .1027 



156 



467 



1,925 



8.80 

 34.40 

 125.30 



0.0561 

 .0736 

 .0651 



0.0546 



.0287 

 .0376 



158.12 



159.5 



141.5 



34.5 

 34.8 

 31 



Table XIII shows there was a smaller number of seeds in the 

 sample from the first pick but that the individual seeds were heavier 

 and the percentage of lint in the two samples was practically the same. 



