10 MISC. PUBLICATION 35, U. S. DEPT. OF AGRICULTURE 
The most important of these insects that eat the boll weevil are 
certain kinds of ants. These ants seek out the infested buds while 
they are still hanging on the cotton plants. When such a bud is. 
found, the ant promptly gnaws through the flower-bud wall and 
feasts upon the juicy grub inside. Often a very large part of the boll- 
weevil grubs and pupe in a cotton field are destroyed in this way. 
The most effective way, however, that nature helps man to control 
the boll weevil is by means of heat and cold. Very hot weather and 
very cold weather are even more distressing to a weevil than they 
are to us. A very cold winter followed by a bright, hot summer 
will generally stop the weevils from increasing to numbers large 
enough to do serious damage to our cotton crop. On the other — 
hand, if the winter is mild and the summer is wet and cloudy, we 
may expect large numbers of weevils and much damage. 
HOW TO FIGHT WEEVILS WITH POISON 
It is not well for us to depend upon nature to do all the controlling, 
because we never can tell exactly what the weather will be during the 
cotton-growing season. It is too uncertain to depend upon tempera- 
ture and dryness, and so we have tried hard to find something that 
would help us to protect our cotton. In all the years since the people 
of the Cotton Belt began to realize how much damage the weevil 
could do, we have tried to find some way of killing the boll weevil. 
Every kind of machine or poison that could be thought of has been 
tried, but without any great success until a few years ago. Finally, 
agents of the Louisiana Crop Pest Commission in 1908-9 tried lead ar- 
senate in dust form with very promising results. However, no general 
or widespread use of this insecticide for boll-weevil control followed. 
In 1914 field agents of the Bureau of Entomology, a division of 
the United States Department of Agriculture, which studies insects, 
began experimenting with a white, powdery poison known as calcium 
arsenate or arsenate of lime. This they dusted evenly on the cotton 
plants during the early morning while dew was still on the leaves and 
buds. Now full-grown weevils, besides feeding on the cotton plants, 
drink the dew that settles there. When the weevils came to feed 
and to drink after the plants had been dusted, each one of them 
swallowed a tiny portion of the poison and died. 
This encouraged the field agents in their work, and a few days 
later they dusted the plants again. After this they found that more 
weevils had died, and so they felt they were on the right track in 
destroying the weevils. A third dusting was finally given, and then 
it was found that there were many more blooms in the field than 
when dusting was started. This meant to the agents that the weevils 
were being killed off faster than they could damage the new blooms 
by laying eggs in the flower buds. 
The agents felt then that they had at last found something that 
would protect the cotton from too great a damage. They thought 
that if the weevils did not become tco numerous later a food crop 
of cotton would be produced. So their field was carefully watched 
throughout the summer, and whenever the weevils appeared to be 
getting thick again another dusting of the calcium arsenate was 
given to it. When fall came there was a good crop of cotton in 
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