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Plaster Beetles

picture of a plaster beetle

Facts, Identification & Control

General Facts

Members of the beetle family Lathridiidae commonly take residence in the walls of newly plastered buildings, which is why they are colloquially referred to as plaster beetles. These moisture-loving beetles are well known for seeking fungi or moulds growing in damp spaces.

Plaster beetles also find their way into mouldy food products and other areas containing moisture and the potential for fungus growth, like bathrooms or leaky ceilings. Adult fungus beetles are capable of flight, attracted to light, and can easily invade homes due to their small size.

Appearance / Identification

picture of a plaster beetle
Considerably small, plaster beetles only measure about 1 or 2 mm in length and are difficult to spot in dark places with their brown colouration. Due to the large number of plaster beetle species that exist, the insects may vary in shape and other physical characteristics, such as the features of their antennae.


Plaster beetles live in damp spaces, where fungus is likely to grow, and can be found throughout the world. In the wild, they seek natural protective barriers such as rocks and water sources or other damp places where mildew and fungi grow.

Ideal habitats for plaster beetles in the home include damp areas such as bathrooms, basements, and crawlspaces. Spots where water consistently leaks or runs, such as water spigots or leaky windows, also make favourable living conditions for the insects. Excessively high humidity in any environment will attract plaster beetles.


Plaster beetles feed exclusively on hyphae and spores of moulds and other types of fungus such as mildew. Though sometimes found in stored food products, they are only attracted to any mould that might be growing within.

Life Cycle / Reproduction

Female plaster beetles are capable of producing roughly 10 eggs and require optimum temperatures of around 24°C to complete a 20-day life cycle. Development time is dependent on the temperature of their environment; it takes longer as temperatures fall, with colder temperatures producing five-month-long life cycles. Before becoming adults, plaster beetle larvae must pupate as part of their metamorphosis during the life cycle.

Problems Caused by Plaster Beetles

Large populations of plaster beetles can be an alarming sight that frightens those who encounter the pests indoors. Plaster beetles may also infest damp or mouldy foods, creating unsanitary eating conditions for household residents and guests alike.

Detection / Signs of Infestation

Plaster beetle infestations may take a while to detect until large numbers of the pests become established in a given area. Signs of infestation then begin to appear as the plaster beetles leave their moisture-laden habitats and congregate near lights or window sills.

Prevention Tips

With the advent of contemporary construction techniques, new buildings are assembled with materials less prone to creating humid conditions ideal for plaster beetles. Ensuring that any new renovations dry out in a timely manner prevents mould growth, which in turn prevents plaster beetles from infesting. Disposing of food before mould can grow also contributes to preventative efforts.

Control / Removal

Employing the use of dehumidifiers is essential in eliminating the moist conditions that attract plaster beetles to basements and crawlspaces. Areas where moisture can be controlled should be checked for leaks and fixed promptly. Ensure that air vents are free-flowing to allow for suitable circulation. Plaster beetle removal may prove difficult for non-professionals, though methods involving vacuum cleaners tend to work well. For particularly large and persistent infestations, pest control professionals can apply treatments that effectively curtail the presence of plaster beetles.