} 
SB 2 
818 | 
C578 
ENT 
2 146. 
Issued February 12, 1912. 
United States Department of Agriculture, — ( 
BUREAU OF ENTOMOLOGY. 
L. O. HOWARD, Entomologist and Chief of Bureau. 
THE MOVEMENT OF THE MEXICAN COTTON BOLL 
WEEVIL IN 1911. 
By W. D. Hunters, 
In Charge of Southern Field Crop Insect Investigations. 
During the season of 1911 the boll weevil was greatly reduced in 
numbers throughout its entire range. This resulted from a com- 
bination of climatic influences extending over a period of about 
three years. So unfavorable were the conditions that the insect 
was exterminated in an area covering about 23,000 square miles in 
the northwestern portion of Texas and the western portion of Okla- 
homa. Undoubtedly these conditions had an important bearing on 
the production of the large crop of 1911. 
The unfavorable conditions for the weevil which culminated in 
1911 began in 1909. In that year drought occurred in Texas and 
Louisiana at such a time as to check the development of the imma- 
ture stages. In 1910 equally adverse conditions prevailed, and the 
pest was further reduced in numbers. At the end of the season of 
1910 conditions arose which gave the insect another very important 
setback. This was a killing frost which occurred October 29. The 
weevils were deprived of their food in all parts of the infested terri- 
tory except along the Gulf Coast and in a few isolated localities else- 
where. The freeze destroyed outright enormous numbers of the 
weevils which were found in the bolls and squares, but the conditions 
immediately following the freeze were even more important in re- 
ducing the infestation to a very low point. After the freeze of Octo- 
ber 29 the weather became warm, and this induced activity on the part 
of the weevils that survived. In fact, temperatures occurred for 
several weeks which caused the insects to require food. An active 
search for food began, but as the cotton had all been killed the ma- 
jority of the weevils which had survived the freeze could _find_no 
food eee ae i oa qaunsonian testityy™ 
—Cir. 9, 
FEG17 1019 
