30 BULLETIN 1393, U. S. DEPARTMENT OF AGRICULTURE 
The running of grain from bin to bin during very cold weather has 
been practiced. The writers observed this method of reducing the 
temperature of grain during the war period when wheat, in being 
transferred, was allowed to fall through the air during zero weather 
from a height of about 25 feet. If grain can be sufficiently chilled 
by running, it can be protected from weevil attack. Even if its tem- 
perature can not be lowered to the point where the cold will prove 
fatal to the insect's life, much good will result from the suspension 
of its activity. 
Since the control of the granary weevil is not different from that 
of grain pests in general, no further discussion of control measures is 
given. 
SUMMARY 
The granary weevil, Sitophilus granarius L., has been known as a 
grain pest from ancient times. Recognized as a distinct species by 
Linne in 1758, it has since been discussed as a pest of economic im- 
portance by many writers but has not been studied seriously, from 
a biologic standpoint, until within the last few years. It is often 
confused with, though easily distinguished from, the closely related 
and more destructive rice weevil, Sitophilus oryza L. 
The granary weevil is considered to have originated in either Asia 
or the Mediterranean region. Unlike other members of the genus 
Sitophilus, however, which thrive best in tropical and semitropical 
climates, the granary weevil is now distinctly a temperate-climate 
species with a world-wide distribution. In the United States it ap- 
pears to be giving way to Sitophilus oryza, and to be the prevailing 
calandrid species only in the more northern States. 
Provided with no effective wings and by nature not very active, 
the granary weevil is found primarily in the granary or storehouse 
and depends upon man for dissemination. It does not appear to be 
well equipped to meet present-day methods of handling and pro- 
tecting grain, with the result that, in the United States at least, it 
seems to be losing some of its importance as a pest in grain and 
certain grain products. 
Like calandrid pests in general, the granary weevil causes the de- 
struction of grain and grain products by the direct feeding of the 
adult beetle and its larva. Adult beetles, being long-lived and vora- 
cious, devour much grain throughout their life. They feed not only 
upon whole grains but upon stock feeds containing cracked grain 
and even upon finely divided products such as flours. The larvae 
feed upon whole grains or upon portions of grains sufficiently large 
to support the larva throughout its entire development. Although 
larvae will not develop in finely divided cereal products such as flours 
and meals, they can probably develop in these when they become 
caked from one cause or another. The adult weevils occasionally 
are destructive by boring holes in the cartons of packaged cereals. 
The granary weevil hibernates during the winter months as adult 
or larva. With the approach of warm spring weather, the adults 
begin to oviposit and the larvae to feed and transform. Newly ma- 
tured adults may remain in the seeds for some time before they 
emerge. Shortly after emergence copulation takes place and is re- 
peated at frequent intervals throughout life. Parthenogenetic eggs 
may be laid occasionally, but do not hatch. 
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