46 Farmers’ Bulletin 1260. 
eration of insects in the maturing grain is usually small, and if the 
grain is cut as soon as ripe, thrashed as soon as dry, and then placed 
in storage in clean, deep bins the damage from this source will be 
very slight. It is when the grain is left in the field long after it is 
ripe that serious infestation results, for the insects increase in one or 
two generations to enormous numbers. In the case of corn in the 
field, only those ears that are damaged or through poor shuck devel- 
opment have kernels exposed are subject to the attack of grain insects. 
Farmers should therefore grow a variety of corn that develops a long 
tight shuck. 
Newly harvested small grains should not be stored unthrashed for 
any length of time. as in this condition they are very susceptible to 
infestation. If promptly thrashed and stored in deep bins, only a thin 
layer on top of the bin is likely to become infested. Corn may be 
stored in the shuck if the husk is long and tight and fully covers the 
tip, but all ears with loose, broken, short, or damaged husks should 
be shucked and stored separately. 
Clean grain should never be stored in old bins, granaries, or store- 
houses until they have been thoroughly cleaned and freed from the 
accumulations of waste grain and other materials harboring grain 
insects. Timbers in bins, granaries, or holds of ships that have be- 
come infested with grain insects should be destroyed or treated before 
being used again. Steel or concrete bins are highly desirable owing 
to the ease with which they are cleaned. 
Bags of all kinds that have previously held grain should not be 
allowed in granaries or warehouses or be refilled until they have been 
sterilized by heat or otherwise freed from insects. The use of tight 
cribs will keep the grain free from infestation by insects that might 
fly in from the outside. 
THE TREATMENT OF INFESTED GRAINS. 
Insects infesting stored grain can be destroyed by the use of heat, 
or by fumigation with poisonous gases. These remedial measures are 
mentioned only briefly in this bulletin. 
HEAT. 
A temperature of 120° to 130° F., maintained for a short time, will 
kill all stages of grain-infesting insects, without injuring the ger- 
minating quality of the grain. Owing to the difficulty of subjecting 
the grain to such a temperature this method of control is used chiefly 
by millers and large grain dealers who are equipped with commercial 
driers suitable for the purpose. 
