PINK BOLLWORM OF COTTON IN MEXICO. 
37 
that when plants are allowed to float free and move with the current 
the bolls will remain on the plants longer. When floating in this 
manner part of the plants are always out of water and, as they revolve 
more or less, the same bolls will not be submerged all the time and 
larvae will survive more than 3 days. To determine how long larvae 
would live in green bolls, sample bolls were placed in a trough 
and examined daily. The bolls floated and larvae lived for 10 days. 
On the eleventh day all of the bolls sank to the bottom and were very 
rotten, and no live larvae were found in them. The results of these 
experiments are summarized in Table XVIII. 
Table XVIII. — Effect of water on pink bollworm larvx. 
Condition of exposure. 
Number treated. 
Time of 
exposure. 
Per cent 
killed. 
Remarks. 
Hours, 
20 
60 
1 pupated afterwards. 
2 pupated afterwards. 
Larva? lived several days. 
44 
70 
20 larva? and 3 pupa?. . 
120 
100 
144 
48 
100 
70 
10 larva? 
Heavy cocoons; 1 adult 
emerged. 
Heavy cocoons. 
20 larva? 
72 
90 
do 
96 
120 
96 
100 
100 
100 
Do. 
10 larva? 
Do. 
Double seed in tube o f water . . . 
10 double seed (5 lar- 
10 double seed (3 lar- 
va?.) 
1 box 
124 
66 
2 larva? alive. 
24 

do 
48 

....do 
72 
40 
box. Counted together). 
do 
96 

do 
120 
50 
2 pupated afterwards. 
Days. 
do 
6.5 
8 
11 
15 
17 
7 
40 
60 
100 
100 
100 
80 
...,do 
.....do 
...do.... 
Bolls floating on water in 
20 bolls (29 larva?) 
Bolls covered with alga? 
trough. (Bolls picked in 
and rotten. 
December, 1918, andstoredin 
20 bolls (12 larvae) 
11 
100 
Do. 
laboratory. Contained many 
20 bolls (56 larva?) 
14 
100 
Do. 
dead larva? not included in 
20 bolls (17 larva?) 
17 
100 
Do. 
count.) 
120 bolls (273 larva?)... 
18 
100 
Do. 
Bolls submerged in water in 
20 bolls (30 larva?) 
7 
77 
2 pupated; bolls covered 
trough (same kind of bolls as 
with algae and rotten. 
above). 
20 bolls (113 larva?).... 
11 
100 
1 larva lived several days; 
bolls rotten. 
Bolls rotten. 
20 bolls (46 larva?) 
14 
100 
20 bolls (14 larva?) 
17 
100 
Do. 
120 bolls (169 larva?)... 
18 
Hours. 
100 
Do. 
Green bolls submerged in slat- 
10 bolls (37 larva?) 
48 
95 
Bolls fermenting and very 
ted box in river. 
sticky. 
10 bolls 
72 
96 
48 
100 
100 
55 
Interior bolls rotten. 
10 bolls 
Badly rotted. 
Plant with green bolls attached 
10 bolls (40 larvae) 
Bolls fermenting. 
floating on surface of river, 
9 bolls (19 larvae) 
72 
98.4 
Interior of bolls rotting. 
Sept. 13, 1919. 
7 bolls (11 larvae) 
96 
Days. 
46 
All of live larvae found in 
two bolls which were not 
submerged. 
143 green cotton bolls placed in 
20 bolls (122 larva?).... 
3 
7.3 
container of water. Water 
20 bolls (125 larva?).... 
4 
3.1 
All dead in two badly de- 
changed daily. 
cayed bolls. 
20 bolls (133 larva?).... 
5 
6.3 
Decaying. 
20 bolls (107 larva?).... 
6 
60.7 
Some in bad state of decay. 
15 bolls (84 larva?) 
7 
31. 5 
Do. 
16 bolls (73 larva?) 
8 
38.8 
Some bolls rather small 
and badly decayed. 
10 bolls (61 larva?) 
9 
44.2 
Bolls decaying rapidly. 
10 bolls (51 larva?) 
10 
60.7 
Some stili Boating; badly 
decayed. 
Badly decayed. 
6 bolls (43 larva?) 
11 
100.0 
6 bolls (29 larva?) 
12 
100.0 
Very rotten. 
