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.
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
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
- 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.
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.
from G.R. Nielsen, University of Vermont Extension, 1999