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JOURNAL OF ECONOMIC ENTOMOLOGY 
[Vol. 13 
to cover the cotton square (bud) itself. 1 It was upon these results 
that the field work of 1909, by Mr. Geo. D. Smith and the senior author, 
was based and which showed an increased yield of cotton averaging 
71 per cent in the poisoned plats of thirteen field experiments. 
The question of whether the boll weevil is killed through ingestion 
of poison with its food or through drinking dew or rain water contain¬ 
ing the poison is an important one, as bearing upon practical work in 
controlling the insect. If mortality is due to ingestion of the poison 
while the weevil is feeding manifestly that method of application will 
be most successful which places the poison directly upon those portions 
of the plant where the weevil is most likely to feed. On the other 
hand, if mortality is due to the weevil being poisoned by imbibing 
dew or rain water on the treated plants, any method of wholesale dis¬ 
tribution of the poison throughout the cotton field will accomplish the 
desired purpose. The machinery used in these two methods of appli¬ 
cation will vary greatly and a correct understanding of the manner 
in which the weevil is poisoned by the use of lead or calcium arsenate 
will, therefore, prevent needless expenditure by the cotton planter in 
machinery which is not adapted to the purpose and also tend to 
increase the efficiency of the poisoning operations. 
For the purpose of determining the point mentioned very careful 
experiments were conducted at Madison, Fla., during the summer of 
1919, the work being immediately in charge of the junior author, 
assisted by Messrs. A. C. Brown, K. E. Bragdon, J. C. Goodwin and 
Walter F. Eberhardt, of the Florida State Plant Board. The work 
was inspected at frequent intervals by the senior author. Office and 
laboratory facilities at Madison were generously made available for 
us by Dr. W. D. Hunter of the Bureau of Entomology. 
The powdered arsenate of lead used in these experiments was rep¬ 
resented by the manufacturer to contain “not less than 30 per cent” 
of arsenic oxide and “less than 1 per cent” of water soluble arsenic. 
The powdered calcium arsenate used was represented to contain 
“total arsenic oxide 40 per cent” and water soluble arsenic “f per 
cent” and met the specifications laid down by Mr. B. R. Coad for 
calcium arsenate suitable for boll weevil poisoning. 
Experiments were made under field conditions and also in the lab¬ 
oratory. The former will be first discussed. 
Field Cage Experiments 
The field experiments were conducted in cages 3x3 feet, 4J feet in 
height, of 16-mesh galvanized wire-cloth, made as nearly insect-tight 
as possible. Cotton plants in the field were treated with calcium 
1 Circ. No. 23, Louisiana Crop Pest Commission, July, 1908. 
