Biscuit Beetle

Do you have black beetles in your food cupboards?

It’s possible you have a biscuit beetle infestation.

These biscuit beetle pests will make their home in stored products including vegetables, spices, cereals, drugs, and even dried flowers.

Biscuit beetles are typically found in kitchen cupboards or pantries. Biscuit beetles will target and damage stored foods like flour.

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Biscuit Beetle (Stegobium Paniceum)

The biscuit beetle, scientifically known as Stegobium paniceum, stands out for its interesting life cycle and effects on products that are preserved. This little but dangerous bug is frequently discovered in pantries and storerooms. It can seriously harm a wide range of dry commodities, including wheat, grains, spices, and dried fruits.

Understanding the biology, behaviour, and control methods of the biscuit beetle is essential for experts in the food sector as well as homeowners who want to safeguard their products against infestation.

Getting rid of Beetles​

These beetles will attack a wide range of stored products including dried vegetables, spices, chocolate, cereals, drugs and even dried flowers.
They commonly get found in association with birds’ nests. The adult beetle does not feed but will fly from the source of infestation and will lay its eggs in other areas.

They are related to the common furniture beetle species and, as one might expect, are capable of chewing into fairly hard materials. An infestation might, therefore, spread into the fabric of a building, behind polystyrene tiles etc.

Stegobium Paniceum: Basic Information

Stegobium Paniceum

Definition and Classification

Stegobium paniceum, commonly known as the drugstore beetle or biscuit beetle, is a tiny brown insect classified under the order Coleoptera and family Anobiidae. It is commonly referred to as the drugstore beetle due to its historical association with infesting pharmaceutical products.

Physical Characteristics

Physical Characteristics

These beetles are small, with cylindrical bodies measuring about 2–3.5 mm long. They’re dark brown to reddish-brown in colour and have distinct longitudinal grooves on their wing covers. Because of their striking resemblance, biscuit beetles are frequently confused with the common furniture beetle, sometimes known as a woodworm. Therefore, it is recommended to call in a professional to confirm the identification of the pest.

What Do Biscuit Beetles Look Like?​

Key Features

Adult beetle length is 2mm – 3mm
Colour – reddish brown
Shape – oval
Covering – a dense covering of yellowish hairs
The head is hidden under the hood-like prothorax. Easily mistaken for the common furniture beetle or the cigarette beetle. The larvae are active initially but become fat, sluggish and eventually incapable of movement. A fully-grown larva is about 5mm long.

(stegobium paniceum)
Eggs are laid individually in foodstuff. Each female produces about 100 eggs. First stage larvae are active and readily crawl through small openings, thereby contaminating packaged foods. Once a food source gets located, the larva becomes less mobile with each moult.

After four larval moults, the insect larva constructs a small round cell from food particles and saliva, in which to pupate. Adults bite their way out of the cocoon and wander in search of a mate, often a considerable distance from the larval development site. In common with other insects, development times are influenced by temperature, relative humidity, moisture content, quantity and quality of food. The following figures are therefore only a guide.


Egg8 – 37
Larvae5 – 150
Pupa9 – 18
Adult in cocoon7 – 12*
*non-feeding42 – 56

The complete life cycle takes between 12-33 weeks.

The optimum temperature range is 25-28°C; development ceases below 17°C.

Habitat and Distribution

Habitat and Distribution

They are widely distributed worldwide, preferring warm climates but capable of surviving in colder regions due to indoor heating.

They are commonly found in pantries and kitchens, infesting dry food items like flour, cereal, pasta, and spices. These beetles are adept at penetrating cardboard, paper, and plastic packaging, making them a persistent nuisance in home storage areas.

Additionally, they hide in the cracks and crevices of shelves and cabinets, coming out only to eat and lay eggs.

Life Cycle of Stegobium Paniceum

Life Cycle of Stegobium Paniceum

The life cycle of this beetle comprises four stages – egg, larva, pupa, and adult beetle.  Temperature, moisture content, food quality, and quantity all affect how quickly an organism develops during its life cycle. There is only one generation per year at cool temperatures (below 15 °C), two at moderate temperatures, and maybe five at warmer temperatures (over 23 °C).

Egg Stage

Egg Stage

Females lay up to 100 eggs at a time, which hatch into larvae within a week. They lay their eggs directly on or near food sources, ensuring that emerging larvae will have immediate access to nourishment. Warmer temperatures generally accelerate development, leading to quicker hatching times.

Larval Stage

Larval Stage

Larvae go through several instars over weeks or months, depending on environmental conditions, before entering the pupal stage. The larval stage is usually the longest stage of the beetle’s life cycle.

Their larvae, which resemble grubs, are white and shaped like crescents. They dig into food products during this stage, which is the most harmful because they leave behind a trail of frass, which is a fine powdery residue.

Pupal Stage

Pupal Stage

The transition from larvae occurs inside silk-like cocoons, where they stay for one to two weeks before emerging as adults.

Pupation usually takes place at the food source or in close proximity to a protective area. The pupae are initially white, but they get darker as they grow. The cells of the larvae reorganise into the adult form during this stage, which is a time of big change.

Adult Stage

Adult Stage

Once matured into adults, these insects live for roughly two months, feeding and reproducing regularly during that time frame. Because adults can fly and are drawn to light, sightings around windows and light fixtures are possible.

Soon after emerging, females start mating and producing eggs to complete the life cycle. Under ideal circumstances, the entire life cycle from egg to adult can be finished in as little as six weeks, allowing for several generations annually.

Behaviour and Diet of Stegobium paniceum

Behaviour and Diet of Stegobium paniceum

As an omnivorous species found mainly near stored food products in homes, it has adapted well to human environments. These beetles exhibit specific behaviours that make them efficient pests in domestic and commercial settings.

Adult biscuit beetles are most active in the evening and at night. Because they can fly and are drawn to light, you may see them near windows and other light fixtures. But despite their ability to fly, they tend to remain close to food sources, minimising their need for extensive movement.

Common items in their diet include flour, cereal, pasta, spices, and dried fruits. They are also known to infest animal-based products such as dried meats, fish and pet foods. Due to their adaptation to low moisture levels, beetles may survive in a variety of situations and can even feed on foods with low moisture content.

Feeding Habits

This beetle can eat an impressive variety of foods, including cereals, spices, dried fruits, leather book bindings, and even lead sheets containing radium! Such a broad diet allows Stegobium paniceum to thrive in diverse environments, from pantry shelves to libraries, where it can cause significant damage to stored goods and archival materials.

The ability of biscuit beetles to consume such a wide range of food items reflects their opportunistic feeding behaviour, where they exploit available resources to meet their nutritional needs. This adaptability is a key factor in their success as pests, as they can infest and proliferate in virtually any environment where suitable food sources are present.

Mating Behaviour

Mating Behaviour

After mating, females lay their eggs near suitable food materials, ensuring ample nourishment once hatched, while males continue seeking other mates until death. This reproductive strategy maximises the chances of survival for Stegobium paniceum offspring, as eggs are deposited in close proximity to food sources where larvae can readily access nourishment.

Male beetles spend the majority of their adult lives engaged in mating activities because they have an innate desire to pass on their genes and protect their lineage.

Environmental factors, population density, and the availability of potential mates all have an impact on mating behaviour of Stegobium paniceum. During periods of optimal environmental conditions and abundant food resources, mating activity may peak, leading to increased reproductive success and population growth. However, factors such as competition for mates, predation pressure, and habitat disturbance can also impact mating behaviour and population dynamics.

Understanding the factors that influence biscuit beetle mating behaviour is essential for developing effective pest management strategies that target reproductive processes and disrupt population growth.

Impact of Stegibrium Panaceum on Human Life

Impact of Stegibrium Panaceum on Human Life

Damage to Stored Products

Stegobium paniceum can cause severe damage to stored food products, resulting in financial losses and potential health risks.

In commercial settings such as warehouses, grocery stores, and food processing plants, infestations can result in the contamination of large quantities of food. This often necessitates the disposal of affected products, which can be costly.

In addition to causing direct damage to food products, Stegobium paniceum can cause structural damage to packaging and storage materials.

The larvae’s burrowing behaviour creates holes and tunnels in cardboard boxes, paper packaging, and even plastic containers. This not only damages the packaging but also compromises the integrity of stored food, making it more susceptible to further infestations by other pests.

In libraries and museums, where the beetles may infest books, manuscripts, and dried plant specimens, the damage can be irreplaceable, affecting valuable and sometimes historical items.

Health Risks

Although they don’t directly harm humans, their presence indicates contaminated food, which could lead to illnesses if consumed.

The presence of beetles and their larvae in food products can lead to contamination with frass, cast skins, and dead insects. Consuming contaminated food can cause gastrointestinal distress and allergic reactions in some individuals.

There is also the risk of secondary contamination, where beetles transfer harmful microorganisms to food products.

Although the beetles themselves are not known to transmit diseases, the conditions they create can encourage the growth of mould and bacteria, further compromising food safety.

Economic Impact

The infestations have been known to shut down businesses temporarily for pest control measures, leading to significant economic losses.

During these shutdowns, businesses face direct costs associated with pest eradication, including professional extermination services, fumigation, and the disposal of infested products. These measures, while necessary to ensure the complete elimination of beetles, can be costly and time-consuming.

Businesses may need to invest in extensive cleaning and sanitation procedures to remove all traces of the beetles and their larvae. This often involves deep cleaning of storage areas, production lines, and packaging facilities. The cost of replacing infested food products, which must be discarded to prevent further contamination, adds to the financial burden.

In the case of severe infestations, companies may also need to repair or replace damaged storage infrastructure, such as shelving, containers, and packaging materials.

Management and Control of Stegibrium Panaceum

Management and Control of Stegibrium Panaceum

If you find beetles walking around, you need to look hard for the food source of the larvae because they like dark, warm, and unoccupied places. Infestations frequently originate from rarely-used dried foods like spices or flour. Getting rid of old and unused food should get rid of an issue.

When no food supply is visible, adult beetles may be observed near air vents and fireplaces. Wasps or birds may have laid these eggs in the attic. Bread that birds have dropped down the chimney shouldn’t be left unattended in fire places either. It should be possible to successfully eradicate this issue by practicing good hygiene and blocking the attic entrance that nest-builders use.

Biscuit Beetle Treatment Prices​

Beetle treatment starts from £125 and this typically gets rid of the infestation. However, the number of treatments required will depend on the level of biscuit beetles present and the size and conditions of the area needing treatment.

To gain the actual cost of control call for an inspection visit and free quote to eradicate the beetles.

Call Your Local Pest Control Office

0114 349 1098

01709 794258

01226 397691

0113 390 4270

Prevention Methods

Regular inspection of stored foods, coupled with good hygiene practises, is key. Storing susceptible items in sealed containers also helps prevent infestation. 

Store dry food products in airtight containers made of glass, metal, or heavy-duty plastic. This prevents beetles from accessing the food and laying eggs. Ensuring that these containers are properly sealed can significantly reduce the likelihood of an infestation.

Additionally, avoid storing food in cardboard or paper packaging, as biscuit beetles can easily penetrate these materials.

Pest Control Techniques

Pest Control Techniques

Insecticides or heat treatment can be used where necessary, along with professional pest management services if required.

When preventive measures and integrated pest management (IPM) strategies are insufficient to control Stegobium paniceum infestations, additional pest control techniques may be necessary.

Insecticides can be used to target adult beetles and larvae, effectively reducing population levels. These insecticides should be applied according to label instructions and safety guidelines, preferably by trained professionals, to ensure their proper and safe use.

Heat treatment is another option for eliminating Stegobium paniceum infestations. Exposing infested items to high temperatures above 60 °C (140 °F) for a specified duration effectively kills all life stages of the beetle, including eggs, larvae, and adults.

Professional pest management services may be required for heat treatment to ensure its effectiveness and safety.

Natural Predators

Some natural predators include spiders, wasps and certain types of beetles, which help control population levels naturally. These predators feed on adult beetles and their larvae, helping to reduce population levels naturally.

By introducing or encouraging natural predators in the environment, it is possible to achieve sustainable pest control without the use of chemical insecticides. However, the effectiveness of natural predators may vary depending on factors such as habitat conditions and predator-prey interactions.

Integrating natural predators into an overall pest management strategy can complement other control methods and contribute to long-term pest control solutions.

Research and Studies on Stegobium paniceum

Research and Studies on Stegobium paniceum

Research plays a crucial role in understanding the behaviour, biology, and ecological interactions of Stegobium paniceum and in developing more effective control methods to manage infestations.

By investigating various aspects of the biscuit beetle’s life cycle, habitat preferences, and feeding behaviour, researchers aim to unravel the complexities of this pest species and identify vulnerabilities that can be targeted for control.

Recent Findings

A study showed that lavender oil effectively repels these pests, while another found improved trapping techniques using specific pheromones.

The volatile compounds present in lavender oil act as a deterrent, preventing beetles from approaching and infesting stored food products. This finding opens up the possibility of using botanical repellents derived from essential oils as part of integrated pest management strategies for controlling biscuit beetle populations.

Ongoing Research

Ongoing research continues to explore various aspects of Stegobium paniceum biology, behaviour, and control. One area of focus is the development of safer and more sustainable pesticides that effectively target biscuit beetles while minimising harm to non-target organisms and the environment.

Researchers are also studying genetic factors influencing beetle reproduction and population dynamics, aiming to identify vulnerabilities that can be exploited for more effective control strategies. Integrated pest management (IPM) approaches are also being studied to see how well they work.

IPM combines multiple control methods to get rid of beetles for good while reducing the need for chemical insecticides.

By advancing our understanding of Stegobium paniceum biology and behaviour and developing innovative control methods, ongoing research aims to provide homeowners, businesses, and pest management professionals with more effective tools for managing biscuit beetle infestations.

Biscuit Beetle Control UK​

Treatment of an infestation of these beetles should start with identifying the source of the outbreak and the extent of product contamination.

Any infested foodstuffs should get destroyed, and the infested areas of the building, shelving, cracks and crevices should be treated using a residual insecticide.

Apex pest control services offer local professional pest control experts to deal with bugs and beetles. Contact us for help and more information on 0114 3491098

Call Your Local Pest Control Office

0114 349 1098

01709 794258

01226 397691

0113 390 4270

Popular Biscuit Beetle Questions​

Also known as Drugstore Beetles, they are small brown beetles 2 to 3 mm long. Biscuit beetles are relatives of the woodworm beetle and may sometimes be mistaken for woodworm. They like to infest hard, dry, starchy foods such as cereals and spices. Biscuit beetles will enter packages which are not tightly closed and will bore through cellophane, tin foil and cardboard to reach foods.

The beetles are not dangerous, but they can be a nuisance when they infest food cupboard. Also, the beetles are often associated with old bird nests in roof spaces.
Biscuit beetles are widespread throughout the world and are likely to have been spread by the transfer of goods.  Its American name ‘Drugstore beetle’ comes from its ability to breed in a dried vegetable matter of any kind, even poisonous substances.

How long Biscuit Beetles Live for

The female biscuit beetles will lay eggs freely in a food source or crevices near to it. The conditions need to be 20ºC or more – this is the average room temperature the eggs will hatch and explore the surrounding
area. The young larvae crawl through tiny spaces to reach foodstuffs.

Biscuit beetles can survive without food for up to eight days. After around two months, depending upon the temperature, the larvae
pupate in a cocoon. Sometimes within the food until 1 to 2 weeks later the adults hatch.
The adult beetle will bore its way through food and packaging to emerge, making holes which can look somewhat like woodworm.

The adult beetles do not eat, and they wander around for about 3 to 4 weeks. Which in that time they will breed and lay more eggs. They will regularly go away from the original site and get
found on work surfaces and other locations in the room. They may sometimes be found
on window sills, as they get attracted by light.

They are small, dark brown or reddish-brown beetles measuring about 2–3.5 mm long with distinct longitudinal grooves on their wing covers.

Their presence may indicate contaminated food, leading to potential health risks and causing severe damage to stored goods, causing financial loss.

Stegobium paniceum is commonly found in residential and commercial environments, particularly in areas where stored food products are stored or processed. They can infest pantry shelves, storage closets, kitchen cabinets, and other areas where food items are stored.

Signs of a Stegobium paniceum infestation include the presence of small, dark brown or reddish-brown beetles near stored food products, as well as the presence of larvae, pupae, or shed skins in infested items. Additionally, damage to food packaging, such as holes or chew marks, may indicate beetle activity.

To prevent Stegobium paniceum infestations, it is important to store dry food products in airtight containers made of glass, metal, or heavy-duty plastic. Regularly clean pantry shelves and storage areas to remove food crumbs and residues that can attract beetles. Inspect new food purchases before storing them, and discard any infested items promptly.

While Stegobium paniceum infestations primarily affect stored food products and non-food items, they are not typically harmful to pets. However, pets may accidentally ingest infested food items, which can lead to gastrointestinal discomfort or other health issues. It is important to store pet food securely and inspect it regularly for signs of beetle activity.

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