POISONING COTTON-BOLL WEEVILS. 3 
ones. When the cotton was picked from these plats rather surprising 
results were secured. Every poisoned plat yielded more than the 
untreated checks, but the most pronounced feature was the much 
greater increase in yield with the larger number of poisonings. With 
four applications a gain of about 15 per cent was secured; with five 
applications this gain was increased to about 35 per cent, while with | 
six applications it was increased about 70 per cent. In other words, 
a single extra application over four more than doubled the gain, 
while two extra applications over four increased the gain between 
four and five fold. As all applications were started at the same time 
and the extra treatments consisted simply of a continuation that 
much later in the season, this seemed to point out very significantly 
the importance of late-season applications. 
POISONING EXPERIMENTS IN 1916. 
The results of these experiments were certainly definite and sig- 
nificant, but it was considered possible that they might have been 
due to some peculiar conditions prevailing during that season and that 
they could not be duplicated during another year. Consequently 
the experiments during the season of 1916 were planned largely to 
check the results secured during 1915, with the important change 
that provision was made for a wider range in the periods of applica- 
tion. In 1916 the applications in the different experiments extended 
from the first appearance of the weevils in June until about the Ist 
of September. On the whole the results in 1916 were just as definite 
as were those of 1915, and the greater importance of the late-season 
applications was very plainly demonstrated. In this connection a 
detailed description of a few of the tests is of interest. 
Probably the most spectacular test of the season and the one 
which aroused the most interest was conducted in a cut of abandoned 
cotton. Poor drainage and excessive rains during May and June 
had prevented cultivation of this cut, and on the 25th of July there 
were no prospects whatever of a crop. The plants were only about 
10 inches high and had been so heavily infested by the weevils that 
there had been no blooms since June. Thus an opportunity was 
afforded to determine what could be accomplished by poisoning under 
the most extreme conditions imaginable. An attempt was made to 
work the cotton out about the Ist of August and a small plat in the 
center of the cut, only six-tenths of an acre in size, was poisoned. 
This poisoning was continued during the month of August and 
surprising results were secured. The weevil infestation decreased 
rapidly in the poisoned plat and the plants soon started blooming and 
continued to bloom practically until frost in spite of the fact that all 
surrounding cotton was very heavily infested with weevils and 
undoubtedly hundreds, if not thousands, were moving into the 
