﻿14 



BULLETIN 1374, U. S. DEPARTMENT OF AGEICULTUEE 



Table 12. — Longevity of resting pink hollworm larvse 



Date examined 



1921 



March 



April 



May - 



June 



July — 



August -- 



September... 



October 



November — 

 December 



1922 



January 



February 



March - 



April 



May..--- 



Bolls of 1920 crop 



Number 

 examined 



100 

 100 

 100 

 100 

 100 

 100 

 100 

 100 

 100 

 100 



100 

 300 

 100 

 600 

 700 



Number 

 of living 



109 

 48 

 55 

 52 

 28 

 9 

 2 

 2 

 4 

 1 



Dead 



larvse and 



pupae 



15 

 21 

 25 

 41 

 46 

 64 

 14 

 39 

 64 

 57 



73 

 143 



50 

 550 

 481 



Per cent 

 living 



87.90 

 69.56 

 68.75 

 55.91 

 37.84 

 12.33 

 12.50 

 4.88 

 5.88 

 1.72 



5.19 

 .69 



1.96 

 

 



Double seed of 1920 crop 



Number 

 examined 



100 

 100 

 100 

 100 

 100 

 100 

 200 

 1,000 

 975 



Number 



of living 



larvae 



Dead 



larvae and 



pupae 



196 

 818 

 750 



Per cent 

 living 



29.89 



32.56 



16.09 



4.39 



3.26 











.12 







Maximum longevity 16^ months. Maximum longevity llj^ months 



I This larva was placed in a pill box. It pupated and a perfectly developed moth emerged on Apr. 10, 

 1922. 



Some of the larvse in the bolls survived longer than those in the 

 seeds. The larvse in both lots of material were attacked by mites, 

 which probably reduced the maximum longevity considerably. In 

 obtaining the figure for maximum longevity given at the foot of the 

 table, the date of the first killing frost in 1920 was used as the starting 

 point. 



Table 13 gives the results of the examination of bolls and seed of 

 the 1921 crop. The bolls were gathered in the field on November 11, 

 1921, and stored on the veranda of the laboratory in sacks. The 

 seed came from cotton picked on November 1 and ginned November 

 4, 1921. Part of this was stored in sacks in a warehouse, and was 

 examined later as a whole. Other parts were stored over winter in a 

 seed house and in a railroad car, and in the spring the double seed 

 were picked out and stored in glass jars in the laboratory. 



Table 13. 



— Longevity of resting pink hollworm larvas 







Bolls of 1921 crop 



Seed of 1921 crop 



Date examined 



Number 

 examined 



Number 



of living 



larvae 



Dead 



larvae 



and 



pupae 



Per cent 

 living 



Quantity 

 examined 



Number 



of living 



larva 



Dead 

 larvae 

 and 

 pupae 



Per cent 

 living 



1921 



100 



15 



30 



100 



95 



67 



60 



140 



135 



175 



449 



700 

 1,100 

 1,200 



296 



51 



39 



93 



29 



2 







1 



1 



1 



1 



1 



1 

 1 



8 



6 



14 



59 



71 



97 



116 



299 



352 



403 



836 



1,366 

 2,945 

 3,184 



97.37 



89.47 



73.58 



61.18 



29 



2.02 







.33 



.28 



.25 



.12 



.07 

 .03 

 .03 



Ounces 









1922 

































8 



7 



1.6 



6.5 



2.0 



25.5 



14 



7 

 68 

 9 



6 

 2 

 1 

 1 



1 

 1 



1 



1 

 1 

 



94 



99 



218 



99 



3,608 



3,382 



2,000 



1,057 



10,564 



1,658 



6 



July ... 



1.98 





.46 





1 





.03 



November 



.03 



December 



.05 



1923 

 January 



.09 



February 



.009 





.0 







N9TE.— The first four lots of seed examined consisted of both single and double seeds; the remaining lots 

 consisted entirely of double seeds. 



