because the head is elongated into a “snout”
that contains the mouthparts. The larvae are
small, white, legless grubs that spend the
entire larval stage inside whole kernels of
grain. Rice maize weevils are capable of
flight; whereas, granary weevils cannot fly.
Lesser Grain BorerThe adult lesser grain
borer is a cylinder-shaped, dark brown beetle
approximately 0.3 cm long. Its head is tucked
so far under the prothorax that it is not visi-
ble from above. It specializes in consuming
grain and grain products and is most com-
monly found in wheat and wheat-based
products, but its eggs can infest corn, rice,
and barley. Adults live 4 to 5 months and are
strong fliers.
Angoumois Grain MothThe adult Angou-
mois moth is a small, buff-colored insect
with a wingspan of approximately 0.125 cm.
The most distinctive identification of this
moth is the long hairs on the fore and rear
wings that give them a fringed appearance.
Larvae bore into the kernels where they feed
and develop. Corn, barley, rice, rye, and oats
are their preferred foods. Adults do not feed
on grain or other food products and do not
cause damage. Larvae may be found devel-
oping in caked material. Pheromone traps
are very effective for monitoring adult male
populations.
External Feeders
Indianmeal Moth: The adult indianmeal
moth has a wingspan of approximately 0.125
cm. The copper-colored band of scales on
the forewings identifies this species. The lar-
vae feed on most grain-based products but
also on chocolate, beans, spices, cocoa, nuts,
and dried fruit. Larvae leave webbing behind
as they feed, frequently causing particles of
dry food to clump. The webbing may contain
frass (feces) that bind equipment such as
motors and augers. Their tendency is to
crawl up vertical surfaces, making observa-
tion of this insect easier than many other
pests. The presence of larvae can identify an
emerging pest population or locate one in
existence. Pheromone traps are effective in
monitoring adult male populations.
A characteristic of this insect and many
other stored product moths, is the ability to
diapause. This period of slowed or sus-
pended growth or dormancy can be initiated
in response to cold temperatures, large pop-
ulation levels, or short photoperiod. An
unheated warehouse that cools during the
winter may give the appearance that control
has been achieved, when in fact the larval
population has diapaused and will resume
activity, typically in the spring, when envi-
ronmental conditions favor growth (Mason,
2003).
Mediterranean Flour Moth: The wingspan
of the adult Mediterranean flour moth is
approximately 2.5 cm. The forewings are
pale gray with transverse black lines and
flecks; whereas the hind wings are gray to
dirty white. Other characteristics, including
diapause, are similar to the Indianmeal
moth. Pheromone trapping is very effective
for this insect.
Flour Beetles: Adult red flower beetles
and confused flour beetles are approxi-
mately 0.3 to 0.5 cm long. Each antenna of
the red flour beetle ends abruptly in a 3-seg-
mented club, while the antennae of the con-
fused flour beetle gradually enlarge. The
sides of the red flower beetle’s thorax are
curved; whereas sides of the confused flower
beetle’s thorax are nearly straight. Red
flower beetles are not strong flyers but have
that capability while confused flour beetles
do not fly. These beetles are major pests of
flour. They rely on other insects or rodents
to first damage the kernels, since they can-
not feed on whole grains. Flour beetles may
be found in grain fines, peas, beans, other
vegetables, dried fruit, chocolate, spices,
rodent baits, botanical drugs, dried milk,
peanuts, and forest products. Both speciesLow-Moisture Food Manufacturing and Storage Sanitation 275