PINK BOLLWORM OF COTTON IN MEXICO. 53 
large numbers of moths were emerging from material at the labora- 
tory which had been taken from this same shed a few weeks before, 
and it is certain that large numbers of moths were emerging in the 
seed shed while the trap was in operation. Light traps have been 
recommended as a means of control by several people. Gough (12), 
Willcocks (7), Ballou (11), and others report catches of thousands of 
moths per night in light traps. Ballou (11) found that most of the 
moths came to the light in the hour following sunset. Some authors 
found lights so attractive to the moths that they were used to deter- 
mine the number of moths emerging from stored material, but in 
Mexico we found that practically none came to the lights. Busck (8) 
in Hawaii also found that the pink bollworm moths were not at- 
tracted to lights. 
Attraction to Fruit. 
Cone-shaped traps of the type used for flies were baited with 
oranges, bananas, apples, mangoes, guavas, and pineapples and were 
repeatedly exposed among the cotton plants with absolutely negative 
results. 
RECOMMENDATIONS FOR CONTROL. 
Too much can not be said and done in encouraging the destruction 
of hibernating larvae. They are the source of infestation for the fol- 
lowing year. If 9 per cent or less of the larvae are able to sur- 
vive the natural mortality of winter and early spring in irrigated 
fields, this small percentage, with the larvae surviving in the seed and 
other places, produces an infestation the following year that causes 
approximately 25 per cent gross loss to the Laguna crop. Every 
hibernating larva killed during the winter or early spring before 
oviposition begins means the cutting off of many thousand larvae by 
the end of the season. The paramount necessity, then, is to re- 
duce the survival of hibernating larvae to as low a figure as possible. 
Burning of Old Stalks and Bolls. 
Just as soon as possible the stalks should be cut and raked up in 
piles. Old bolls, sticks, and trash of all descriptions to which larvae 
may be attached should be carefully picked up and burned with the 
the stalks, the main object being to burn everything in the field that 
contains larvae or would be likely to afford protection for hibernating 
larvae. If possible, the cutting and piling of the stalks should be done 
while the plants are still green, in this way minimizing the labor and 
increasing the effectiveness of the operation. Green stalks will 
retain most of their bolls, which shatter when they are cut dry. Just 
as soon as the piles lose their green color and become more or less 
dry they should be burned. Better results can be gained by waiting 
for this drying to take place rather than by burning the plants while 
they are yet green. Ordinarily the old stalks are cut and burned in 
