BUREAU OF ENTOMOLOGY AND PLANT QUARANTINE 
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insects except the cadelle (an important pest ) without injury to the 
grain. 
The question of the extent to which grain in transit becomes infested 
by contact with infested cars is becoming increasingly important. A 
study of grain freight ears arriving at railway yards for cleaning 
revealed that about 57 percent of such cars contained insects prior to 
the peak of the shipping season. This infestation rose to 91 percent 
after the peak shipping season had passed. Clean flour placed in 
wooden box cars that had been treated in various ways to eradicate 
insects was quickly invaded by insects in large numbers, proving that 
fumigation of such cars was not effective. Lining these cars with 
paper previous to loading retarded infestation but failed to prevent it. 
Claims have been made by commercial concerns that certain dust- 
like substances added to stored grain were effective in protecting it 
from attack by insects. Tests were made of the insecticidal value of 
finely divided dustlike substances such as lime, sulfur, wood ashes, soy- 
bean flour, and prophyllite. when mixed with wheat in the proportions 
of 1 and 2 pounds per bushel. These all failed to prevent insects from 
breeding in it at a dangerous rate and proved ineffective and 
impractical. 
A study of the comparative action on the germination of corn 
of four common fumigants showed that with dosages fatal to in- 
sects, and exposures for periods of 72 hours at a temperature of 
95° F., hydrocyanic acid, carbon disulfide, and ethylene dichloride did 
not adversely affect the germination of corn having a moisture con- 
tent of from 10 to 16 percent. When treated with chloropicrin at 
a rate of 3 pounds to 1,000 bushels, corn having a moisture content 
of from 12 to 16 percent showed some injury after an exposure 
of 12 hours. 
That insects cause serious loss to the rice crop in storage was shown 
by studies recently conducted. In four varieties of rough rice 
stored for 1 year the loss from insect attack was 12.9 percent. The 
loss from this source in clean rice was 69% cents per barrel, and its 
moisture content influenced the degree to which it was injured. A 
moisture content below 10 percent was insufficient to sustain insect life, 
but practically all stored rice contains more moisture than this — in 
fact, a moisture content of about 14 percent is desired for good 
milling condition. 
In the search for an efficient fumigant for clean rice, it was found 
that methyl bromide proved satisfactory at atmospheric pressure. 
When clean-sacked brewers' rice was fumigated with this chemical 
at 70° F., a dosage of IV2 ounces per 1,000 pounds of rice gave a 
complete kill after 4 hours' exposure. A dosage of one-half ounce 
per 1,000 pounds was effective after an exposure of 12 hours. In 
a subsequent mass fumigation of %y 2 million pounds of rice con- 
tained in burlap bags stored in a tight concrete wa rehouse of 
365,000 cubic feet capacity, a dosage of 0.85 ounce of methyl bro- 
mide per 1,000 pounds of rice killed all insects after an exposure of 
42 hours. Fans were used to distribute tin 1 gas during fumigation. 
INSECTS ATTACKING FORAGE CROPS 
Completion of the studies on survival of alfalfa weevil adults in 
baled hay and straw showed that they can survive in the bale.s for 
