STUDIES OF THE PINK BOLLWORM 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 soil 
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 
77.5 
12.4 
10.1 
24.9 
33 
42.1 
1 Difference between total of last two columns and total of first three. 
Although this summary 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 larvae 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. y^m 
Table 38. — Average number of living and dead larvas,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 
0.10 
.15 
5 
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 
12.6 
- 9.2 
5.4 
5.6 
4.4 
4.1 
3.6 
3.6 
3.8 
■'l-'"-" 3.'4' 
. 3.0 
;••"'" 4.8 
r 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 
13. 
1. 18 . 38 
\ 1.86 
20-_ . 
1.58 
.82 
.72 
.62 
.52 
.51 
.30 
.23 
.27 
.14 
.21 
,: .15 
: .18 
:, .19 
1 .18 
.15 
J 
27 . . 
Jan. 3 - 
10. . - . . 
r L4 
17 --. 
24. . . _ 
7 _ . 
14 
21 
28 ' " 
Mar 7 
21 
28 
11 
