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University
of Rhode Island GreenShare Factsheets
Larder
Beetle
Dermestes lardarius (Linn.)
Coleoptera: Dermestidae
Large numbers of small, brown, hairy larder beetle larvae
often appear suddenly in the spring, alarming homeowners. Larder
beetles attack all products of animal origin, including feathers,
horn, skins, ham, bacon, dried beef, hides, hair, beeswax,
and similar products. In recent years, they have been found
in increasing numbers in dry pet foods containing a mixture
of cereal and animal products. Adult beetles are occasionally
found on flowers, where they feed on pollen.
The adult is a small, black beetle, 6 to 9 mm (1/4 to
1/3 inch) in length, with a pale, yellowish-brown to reddish
band across the anterior half of its wing covers. On this band
are six black dots, three on each side of the middle line.
The larder beetle larva tapers towards both ends and may reach
16 mm (5/8 inch) when fully grown. The larva has a brown, hairy
body, white undersurface, and two short, curved stiff spines
on the top of the last abdominal segment.
Larder beetles usually enter homes in May and June seeking
food on which to deposit their eggs. If no food can be found,
the beetles deposit their eggs in cracks and crevices about
the pantry and other areas where the larvae will be able to
find food. Larder beetles frequently follow heavy cluster fly
infestations, as the beetles readily feed and lay their eggs
on the fly carcasses. Large numbers of nearly full-grown larder
beetle larvae consume the last of the cluster flies or other
food upon hatching, work their way out of the partitions in
the house, and wander about, ending up in sinks, tubs, bureaus,
beds, etc. This invasion can last from two to four weeks. Similar
problems can result from mice, birds or squirrels nesting in
the walls. Under favorable conditions, there may be more than
one generation per year. The larder beetle can complete its
life cycle in 40 to 50 days.
- Controlling cluster flies is often helpful in reducing
larder beetle infestations (see URI Greenshare Factsheet
on cluster flies). Seal baseboards
and other possible openings into attics and partitions.
- Keep smoked meats in cold storage. Farm-cured meats
should be carefully wrapped in cloth or paper immediately
after smoking.
- Store all meat products in sealed containers.
- Catch the beetles and larvae by hand and destroy. Use
cheese as a bait to trap the beetles.
- Infestations in dry pet food may be controlled by
heating to 135 degrees F for 30 to 45 minutes or by freezing
for several days. Microwaving should be equally effective.
Adapted from G.R. Nielsen,
University of Vermont Extension, 1999
Pesticides
are poisonous! Read and follow all safety precautions on labels.
Handle carefully and store in original containers out of reach
of children, pets or livestock. Dispose of empty containers
immediately, in a safe manner and place. Pesticides should never
be stored with foods or in areas where people eat.
When trade names are used for identification, no product endorsement
is implied, nor is discrimination intended against similar materials.
Be sure that the pesticide you intend to use is registered for
the state of use.
The user of this information assumes all risk for personal injury
or property damage.
For more
information, call the URI CE Gardening and Food Safety Hotline
at 1-800-448-1011 or (401)874-2929 from outside Rhode Island;
Monday-Thursday between 9 am and 2 pm.
University
of Rhode Island Cooperative Extension provides equal program
opportunities.
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