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Larder Beetle

Larder Beetle Adult and Larva
Larder Beetle Adult and Larva
Larder Beetle Larva
Larder Beetle larva

Biology

Two species of beetles associated with poultry manure and litter accumulations in the Northeast are the lesser mealworm or darkling beetle, Alphitobius diaperinus, a pest of stored grain products; and the larder beetle, Dermestes maculatus, long recognized as a pest of hides, skins, and furs. Adults and larvae of both species can become extremely abundant in poultry manure and litter.

Both beetles can cause extensive damage as the mature larvae bore into structural materials, apparently seeking a safe pupation site. The lesser mealworm is also a vector (transmitter) and serves as a reservoir for several poultry disease pathogens such as acute leukosis (Marck’s disease), fowl pox, numerous pathogenic Escherichia coli serotypes, several Salmonella species, and tapeworms. Large beetle populations may become a public nuisance at cleanout time because of adult migration from the fields where the manure is spread into nearby residential areas.

Hide Beetle, Dermestes maculatus

Hide beetles are larger than darkling beetles, about 1/3 inch long, and dark brown on the top with a mostly white undersurface. Hide beetle larvae are similarly colored, thickly covered with long brown hairs, and grow to about 1/2 inch long. Scavenging hide beetles feed on bird carcasses, skins, hides, feathers, dead insects, and other animal and plant products. Broken eggs and dead birds in the manure enhance beetle populations, although large beetle populations may develop even with good sanitation.

Eggs are laid on manure and litter surfaces. Larvae hatch from eggs in 2 to 7 days, depending upon the temperature and relative humidity, and pass through an average of seven instars in 23 to 41 days or more. Larvae normally remain in the manure, but large numbers will migrate from the pit to find a safer pupation site or to move away from unfavorable conditions in the manure. Larvae bore into wood posts, beams, paneling, drywall, and insulation to create a protected pupation chamber. Adults are rarely involved in boring. Adults emerge in 6 to 15 days and live 60 to 90 days.

Management

Once a poultry house becomes infested, control is difficult because beetles migrate throughout the house, and pupation occurs in wood and insulation. A thorough house cleaning, combined with chemical control when the birds are removed, will usually suppress the population for a short time. Migration may be reduced by applying insecticide sprays to the pit walls and posts.

Applying dusts and sprays to manure and litter is fairly effective, but it can destroy any fly biological control agents present. Attaching well-sealed, angled, metal flashing to pit walls at the masonry-frame wall joints and to posts can help reduce immature beetle migration out of the pit; however, the rapid accumulation of dust and debris may make the flashing ineffective. Even if the flashing is effective, beetle dispersal into the community at cleanout time is a potential problem.

During spring and summer, when fly and beetle dispersal is a major concern, manure that must be removed from the building can be piled and tarped to kill developing pests. It is important that the manure be sealed completely under the tarp and the pile be placed in direct sunlight. Seal the tarp by filling 4-foot-long sections of 4-inch PVC pipe with sand, capping them, and placing them on the edges of the tarp around the base of the pile. When uncovering the manure pile, take care to avoid inhaling the excessive gas that accumulates under the tarp. Following a minimum of 2 weeks under the tarp, manure can be spread on fields without concern for pest dispersal.