RED & CONFUSED FLOUR BEETLE
Common
Name: Red flour
beetle / Confused flour
beetle
Scientific Name: Tribolium
castaneum / Tribolium
confusum
Introduction. The red flour
beetle gets its common
name from its coloration
and its habit of infesting
flour. It is one of
the most important pests
of stored products found
in the home and in grocery
stores. It is of Indo-Australian
origin and now occurs
worldwide in the warmer
climates. In the United
States, it is found
primarily in the southern
states.
The confused flour beetle
apparently got its common
name because of the
confusion regarding
its identity. It is
one of the most important
pests of stored products
found in the home and
in grocery stores. Although
of African origin, it
now occurs worldwide
in cooler climates.
In the United States,
it is more abundant
in the northern states.
Recognition. Adults of the both the
red and confused flour
beetles measure 1/8
inch long, and are reddish–brown
in color. However, red
flour beetle antennae
terminate in an abrupt,
3-segmented club. Whereas
confused flour beetle
antennae gradually widen
from the head outward.
Wings functional but
commonly flies only
short distances. Also,
the red flour beetle
has functional wings
but only flies short
distances; while the
confused flour beetle
is never observed flying.
Full-grown larvae of
both species measure
1/8 to 1/4 inch long
are yellowish-white,
and wiry in appearance.
Similar
Beetles. (1)
The black (Tribolium
audax) and false black
(Tribolium destructor)
flour beetles are black
and longer (about 1/4
inch) than the red and
confused flour beetles.
(2) The lesser mealworm
(Alphitobius diaperinus)
is also longer (about
1/4 inch in length).
(3) The yellow (Tenebrio
molitor) and dark (Tenebrio
obscurus) mealworm beetles
are dark brown to black,
and much longer (about
1/2 to 3/4 inch).
Biology. The red and confused
flour beetle females
deposit about 300 to
500 clear-white sticky
eggs on or among food
materials in cracks,
in bags, or through
the mesh of sacks containing
food. The females live
for 2 to 3 years and
lay 2 to 3 eggs per
day.
The eggs hatch in 5
to 12 days into brownish-white
larvae, which go through
5 to 18 instars (usually
7 to 8) and reach maturity
in about 30 days under
optimal conditions.
The life cycle (egg
to egg) can be completed
in only 7 weeks, or
it may require 3 months
or longer. In heated
storage facilities and
processing plants, there
are 4 or 5 generations
annually.
Habits. These beetles are unable
to feed on whole kernels
or undamaged grain.
They have been recorded
attacking grains and
grain products, peas,
beans, shelled nuts,
dried fruits, spices,
milk chocolate, drugs,
snuff, cayenne pepper,
herbarium and insect
specimens, and other
museum display and collection
items. They are mainly
attracted to flour of
high moisture content.
Although they do not
injure humans, flour
beetles do impart a
disagreeable odor and
taste to the flour and
food products they infest.
Red flour beetle adults
can fly and are attracted
to light. Confused flour beetles often crawl
towards light sources.
Cultural
Control & Preventative
Measures. The
first step towards stopping
an infestation of red
or confused flour beetles
is locating and, if
possible, removing the
food source(s) or excluding
the breeding site(s).
Beetles, larvae and
pupae can be removed
using a vacuum cleaner
fitted with a hose attachment.
Flour, meal, cereal
and other vulnerable
items should be stored
in airtight, thick-walled
containers until needed.
Infested items of value
can be heat-treated
in a warm oven (140ºF)
for 30 minutes to destroy
all stages, or deep-frozen
(0ºF or colder
for 72 hours) to destroy
eggs, larvae and adults
(but not all the pupae,
if present). Rodent
bait that has been stashed
away in structural voids
by invasive mice, as
well as dry animal carcasses
in structural voids,
may be infested by beetle
larvae and can be difficult
to locate and treat.
Infestations in large
commercial settings,
such as food processing
plants, mills and warehouses
must be addressed via
an aggressive on-site
cleaning and sanitation
program. All floor areas
(including edges and
crevices), equipment
surfaces, beams, bracework,
exhaust fan components
and other interior surfaces
on which processed cereal
and grain dust may accumulate,
must be thoroughly cleaned.
Professional
Control. A
Rottler pest management
professional will assist
in locating red and
confused flour beetle
breeding sources and
making recommendations
for preventing re-infestation.
A spot treatment of
an infested structural
void or a crack and
crevice treatment into
cabinet seams and shelf
junctures using non-residual
or residual insecticide
aerosol or dust formulations
may be applied by the
technician to stop additional
pest breeding.
Larvae that form pupae
in well-concealed cocoons
during late summer and
autumn may not give
rise to new adult moths
until the following
spring. Therefore, good
sanitation and food-storage
practices must be maintained
perpetually, once an
Indian meal moth infestation
of has been detected
and treated.
When dealing with beetle
infestations in large
commercial settings,
such as food processing
plants, mills and warehouses,
Strategically placed
insect pheromone traps
and insect light traps
are important for monitoring
infestations of these
and other insect pests.
Rottler pest management
professionals can install
and monitor these devices
to help determine the
internal breeding source(s)
of stored product pests
so that they can be
discovered and removed.
If necessary, fumigation
of the facility or space
treatment using ULV
or thermal fogging equipment
with a synergized pyrethrum
insecticide may be necessary to eliminate large pest
populations.
Locations
Serving the St. Louis Metropolitan area since 1956, including
Arnold, Ballwin, Chesterfield, Crestwood, Creve Coeur, Des Peres,
Fenton, Florissant, Kirkwood, Maryland Heights, Overland, St.
Charles, Webster Groves, Wentzville and surrounding areas.
In Illinois: Belleville, Collinsville, Edwardsville, Columbia,
Madison, Waterloo, O’Fallon, Granite City, Alton, St. Clair, Monroe
and surrounding areas.
Columbia & Jefferson City, MO and surrounding areas.
