PINK BOLLWORM OF COTTON IN MEXICO. 
27 
Table XII. — Results of experiment to determine damage caused by feeding of the pink 
bollworm in the blooms of cotton. 
Blooms. 
Number 
of tags. 
Dropped 
off. 
Set bolls. 
Per cent of 
blooms 
dropped. 
343 
343 
140 
232 
203 
111 
40.8 
Infested 
67.6 
From the above table it will be seen that 40.8 per cent of the normal 
blooms did not set bolls, but 67.6 per cent of the infested blooms did 
not set bolls, a difference of 26.8 per cent. Granting that under 
favorable conditions the natural tendency of the plant will be to 
reset these fruits, it is obvious that 26.8 per cent of the blooms will 
make bolls at a much later date than they normally would, thereby 
subjecting them to a far heavier infestation, hence a greater amount 
of damage. The later maturity of the crop due to shedding of the 
early squares would also greatly increase the damage by the boll 
weevil in countries where this insect is present. (See Table XI 
on " Progress of infestation. ") 
The rate of monthly increase of the infested blooms in a given 
field is shown in Table X. 
DAMAGE TO BOLLS. 
In estimating the damage caused to the mature bolls (PL I), 
pickable as well as nonpickable cotton must be considered. By 
pickable cotton is meant cotton that is picked, ginned, and marketed 
from the beginning to the end of the crop; by nonpickable cotton, 
the bolls or portions of bolls that are left on the plants as unfit for 
picking, due to damage by the pink bollworm. 
PICKABLE COTTON. 
To arrive at a conclusion as to the extent the cotton taken from 
the fields is damaged, a 100-pound sample of seed cotton was taken 
from each picking in each experimental field. These samples were 
taken by picking all the open cotton on about every twentieth 
plant in each row, in this manner obtaining as nearly as possible a 
composite average sample of the cotton open in the field on that 
date, After the sample was taken the remaining open cotton was 
picked in the customary manner, thereby guarding against the 
possibility of mixing any of the first and second pick cotton in the 
taking of the later samples. 
The samples were stored until the end of the season and then 
ginned separately, using a small 10-saw sample gin. A gin sample 
of approximately 2 pounds of lint and a sample of seed weighing 
about 2 pounds were taken from each of the field samples at the 
time of ginning. 
