﻿STUDIES OF THE PINK B0LL.WORM IN MEXICO 



45 



Table 37. — Distribution of bolls and larvae before and one week after cutting of 



stalks in field 



[Number per square yard] 





Before cutting stalks 



After removing stalks 





On 

 stalks 



On 



surface 



In soO 



Removed 

 with 

 stalks 



On 



surface 



In soil 



Bolls 



17.2 

 39.7 



3 



6.36 





18.2 

 12.76 



12 

 16.9 





Larvae . ... 



5.2 



21.6 







Per cent of total larvae 



77.5 



12.4 



10.1 



24.9 



33 



42.1 







1 Diflerence between total of last two columns and total of first three. 



Although this sunmiary is a calculation based on several separate 

 observations and must be considered as only approximate, it should 

 be fairly reliable. The figure of 12.76 larvae removed in 8.2 bolls 

 gives an average of 1.56 larv« per boll. Usually the larger and 

 better-matured bolls remain on the stalks, and a higher worm con- 

 tent is found in them than in those that are shed. It seems safe to 

 say, however, that in this field not more than from one-fourth to 

 one-third of the total larvae were destroyed by cutting and burning 

 the stalks. The stalks were cut by hand and raked up with a hay 

 rake. Afterward they were burned. 



Soil examinations at the same five points in this field were con- 

 tinued weekly, and at each time 100 bolls were collected from the 

 surface for examination. Table 38 summarizes the results of these 

 examinations, including only those made after the stalks had been 

 cut. 



Table 38. — Average number of living and dead larvse per square yard in the soil and 

 per boll in bolls on the soil after removal of stalks 





Per boll on the 

 surface 



Per square yard in the soil 



Date 



Living 



Dead 



Total 

 living 



Total 

 dead 



Living 



in bolls 



and locks 



in the soil 



(average) 



Dec. 2 . . . - 



1.3 



1.54 

 1.18 

 1.58 

 .82 

 .72 

 .62 

 .52 

 .61 

 .30 

 .23 



0.10 

 .15 

 ..38 

 .27 

 .14 

 .21 

 .15 

 .18 

 .19 

 .18 

 .15 









5.- 



13 



21.6 

 20.4 

 11.4 

 20.6 

 15.0 

 16.2 

 13.2 

 15.8 

 9.8 

 14.4 

 11.4 

 9.2 

 13.0 

 6.4 

 12.0 

 9.2 

 6.4 

 5.0 

 4.4 



4.1 

 3.6 

 3.6 

 3.8 

 3.4 

 3.0 

 4.8 

 3.4 

 5.2 

 2.2 

 2.8 

 4.8 

 1.4 

 1.6 

 7.2 

 4.0 

 3.2 

 2.6 

 4.0 



[ 1.86 



20. ... 



J 



27 





Jan. 3. . 





10 



f '-^ 



17 





24. • . 





Feb 1 





7. . , 





14 





21 









28 









Mar 7 









14. . ... 









21 









28 









Apr. 4 









11 

















