PINK BOLLWORM OF COTTON IX MEXICO. 



15 



Table V. — Number of pin]; bollworm larvse- found in single and double seed of cotton 



picked at different dates. 





Date 

 picked. 



Date 

 exam- 

 ined. 



Double seed. 



Single seed. 



Weight of sample. 



Number 

 double 

 seed. 



Number 

 of lar- 

 va? in 

 double 

 seed. 



Per cent 

 of total 



larvse 

 in double 



seed. 



Number 



single 



seed 



damaged. 



Number 



of larvse 



in single 



seed. 



Per cent 



of total 



larva? 



in single 



seed. 



First picking: 



1919. 

 Aug. 4 

 Aug. 

 Sept. 23 



Oct. 16 

 Nov. 2 



1918. 

 Dec. 3 

 Dec. 10 



1919. 

 Oct. 10 

 Oct. 8 

 Oct. 22 



Oct. — 

 Oct. — 



Mar. 30 

 Mar. 20 











30 

 234 



106 

 36 









 



29 

 30 



95 



26 





 

 



58 

 56.6 



30 



38 

 108 

 156 



121 

 467 



715 

 597 



2 

 1 

 3 



21 

 23 



250 



100 





100 





100 



Second picking: 



41 





43.4 



Third picking: 



70 





53 ! 67 









1 One pupa in lint, not counted in above. 



2 Two pupse in lint, not counted in above. 



This table shows that no double seed was found in cotton from the 

 first picking, that 57.3 per cent of the larvse were found in double 

 seed from the second picking, and that the percentage fell to 31.5 

 in the third picking. It is probable, however, that occasional double 

 seeds are formed during August and September or in the first picking. 



Taking an average of these figures and reducing them to a 1 -pound 

 basis, the number of larvse per bale present in the seed from the 

 different pickings can be calculated. It is thought that no live larvse 

 pass through the gins in the lint, and that many of the larvse in the 

 seed are driven out during the cleaning and ginning. It is certain 

 that the large number found in seed when hand-ginned were never 

 found in commercially ginned seed. 



Table VI. — Number of pink bollvjorrn larvse found per pound and the estimated number 

 per bale in cotton from different pickings. 





Double seed. 



Single seed. 



Weight of sample. 



Number 

 double 

 seed. 



Number 



larvse 



in 



double 

 seed. 



Esti- 

 mated 

 number 

 of lar- 

 vse per 

 bale in 

 double 



seed. 



Per cent 

 of total 



larvae 



in 

 double 



seed. 



Number 

 single 

 seed 

 dam- 

 aged. 



Number 

 larvse 



in 

 single 

 seed. 



Esti- 

 mated 

 number 

 of lar- 

 vae per 

 bale in 

 single 



seed. 



Per cent 

 of total 



larvse in 

 single, 

 seed. 



Esti- 

 mated 

 number 

 of lar- 

 vse per 

 bale in 



single 



and 

 double 



seed. 



First picking: 



1 pound 



Second picking: 



1 pound 



Third picking: 



1 pound 





 43 



189 







39 

 161 







58,500 



241, 500 





 56. 5 

 28.5 



121 



392 



1,749 



6 



30 

 404 



9,000 



45,000 



606,000 



100 

 43.5 

 71.5 



9,003 



103, SCO 

 847,500 



Gough (-5), in one of his earlier publications, states that there are 

 two generations of the hibernating larvse, the older generation con- 



