four or five on sweet corn. Over the 10-year period corn growers 
spent at least $13,900,900 on insecticidal control of the corn 
porer. The Federal and State Governments expended approximately 
$300,800 from 198 to 1951 in service surveys that contributed 
to control. 
The southwestem corn borer is a pest of corn in parts of Kansas, 
Oklahoma, Texas, New Wexico, Colorado, and Arizona, and in a few 
counties in Arkansas and Missouri. The loss increased from $2 
million in 192 to $22 million in 1951, averaging $9,660,000 annually. 
The larvae feed on the leaves of the young corn plants, retarding 
their growth. They also damage the ears, and tunnel in the stalks, 
weakening, stunting, and sometimes killing the plants. This gird- 
ling and tunneling in the lower part of the stalks in the fall 
causes many plants to fall over, and their ears are lost at harvest- 
time. 
Control of this pest is difficult. Insecticides have not proved 
practical, but certain cultural practices are of some help in re= 
ducing damage. 
Cotton 
The reduction in cotton yield caused by the boll weevil has been 
estimated by the Bureau of Agricultural Economics annually since 
1909. The average reduction in yield for the 13 States where this 
weevil normally causes damage has been 10.1 percent. These States 
are Virginia, North Carolina, South Carolina, Georgia, Florida, 
Missouri, Tennessee, Alabama, Mississippi, Louisiana, Texas, Okla- 
homa, and Arkansas. Damage varies greatly between States and also 
between years. In Missouri, for instance, damage was recorded in 
only 9 of the lh years, and the highest loss was only 7 percent 
in 1918. In Virginia, on the other hand, there was an estimated 
loss of 63 percent in 195. 
To the direct loss must be added the cost of control. This 
amounted to $3,200,000 annually during the S-year period 1926-30, 
when calcium arsenate was the only insecticide recommended and when 
only a small portion of the total cotton acreage was treated. Since 
1947, when the organic insecticides came into general use, a much 
larger portion of the total acreage has been treated. In 1952, a 
year of light insect damage to cotton, the cost to farmers of in= 
secticides for the control of all cotton insects was $75,000,900, 
the greater part of which was for boll weevil control. 
The costs of machinery and of custom application of the insecti- 
cides are also large. Many thousands of farmers own their spraying 
or dusting equipment, costing many millions of dollars. Custom 
applications by airplanes have greatly increased during recent years. 
The average cost of applying insecticides to cotton in this manner 
is about $0.50 per acre for dusts and $0.75 for sprays. 
3767) 
