Tiny holes in a pack of dried pepper or in coffee beans, and sesame-seed-sized brown beetles coming out of the cabinet: this is the drugstore beetle (Stegobium paniceum) or its relative the cigarette beetle (Lasioderma serricorne). Both are well-known stored-product pests.
Part of the household beetles guide; here we explain how to tell them apart and how to clean your home of them.
Size: Small reddish-brown beetles about 2 to 3 mm long, and both species can infest stored dry foods.
Food: Drugstore and cigarette beetles feed on flour, spices, herbs, pasta, tobacco, and other dry foods.
Sign: Small insects inside packages, crumbs and tiny holes in bags, and an unfamiliar smell in stored foods.
Common mistake: Spraying shelves without discarding contaminated packages; the source is inside the food itself, not around the shelf.
Rule: Throw away every suspect package, vacuum the shelves, then keep dry goods in airtight containers.
How Do You Tell Them Apart?
They look alike, but some details tell them apart:
- Size: About three millimeters each.
- Drugstore beetle: Mostly reddish-brown, with lengthwise lines on the wing covers, and antennae ending in three large segments.
- Cigarette beetle: Light brown and smooth with no lines, and saw-toothed antennae.
- Flight: Both fly toward light.
- If touched, they curl up and play dead.
What Do They Eat?
Both feed on a very wide range of dry materials:
- Spices and herbs: Pepper, turmeric, cumin, tea, and medicinal herbs.
- Dry foods: Flour, pasta, biscuits, and nuts.
- Animal foods: And bird seed.
- Non-food materials: Books, paper, tobacco, and dry medicines.
Signs of Infestation
- Tiny holes: In packages, grains, and tablets.
- Fine powder: At the bottom of the package, from larval droppings.
- White larvae: Small, C-shaped, inside the food.
- Adults: On windows or on shelves.
Elimination Plan
The source is almost always an infested package, and treatment rests on removing it and cleaning around it.
- Inspect all packages: Dispose of the infested ones in a sealed bag outside the home.
- Freezing: Suspect but sound foods are frozen for a week.
- Clean the shelves: With a vacuum along cracks and corners, then wipe them.
- Glue traps: To monitor adults.
- Treat cracks: With a residual spray on empty shelves only when necessary.
How Do You Prevent Their Return?
- Airtight containers: Glass or metal.
- Buy quantities that will be used: Within months.
- Rotate stock: Oldest first.
- Inspect new food: Before putting it in storage.
Life Cycle Length
In warmth the life cycle from egg to adult is completed in about two months, which means several generations a year.
- Larvae: Feed for weeks inside the food.
- Pupae: Transform inside a small cocoon.
- Adults: Live a few weeks, feed little but lay eggs.
Monitoring Tools
- Pheromone traps: Specific to the cigarette beetle, to catch males.
- Glue traps: Near shelves and windows.
- Monthly inspection: Of spices and long-stored foods.
Why Do They Infest Spices in Particular?
Dry spices are rich in oils and nutrients and are kept in warm places in the kitchen, making them an ideal environment for these beetles. Larvae can even grow in materials that others avoid, such as hot pepper and curry. That is why infestation often appears from an old bag of spices or a forgotten tea tin, then moves from it to the rest of the pantry through flying adults.
How Do You Inspect Your Pantry Step by Step?
- Take all packages out and place them on a clean surface under good light.
- Inspect open and old packages first: spices, herbs, nuts, and pet food.
- Look for tiny exit holes and for fine powder or silken threads.
- Shake a suspect package over a white sheet of paper so larvae and adults show up.
- Inspect shelf corners and cracks, and behind them, with a flashlight.
Common Mistakes
- Leaving packages open or poorly sealed for months.
- Throwing away only one package and neglecting the neighboring ones.
- Cleaning shelves with water alone without removing residue from the cracks.
- Relying on spray pesticides instead of removing the source.
When should you visit a branch?
If infestation appears in a commercial store or restaurant kitchen, or in a library or museum holding books and manuscripts, or if it returns despite cleaning the whole pantry, visit your nearest Orkida branch with a photo or a sample and we will point you to the right product.
Tips for Storing Spices and Dry Medicines
Store spices in tightly sealed glass or metal containers, and avoid keeping large quantities of ground spices for a long time. Buy small quantities that will be used within months, and keep dried herbs and herbal preparations in closed containers away from heat. Keep dry medicines and supplements in a closed cabinet away from the kitchen.
How Do You Treat Books and Paper?
If infestation appears in books or papers, take them out and inspect the covers, edges, and surrounding shelves. Put suspect books in a sealed bag and freeze them for a suitable period, then shake them out well and move them to a clean place. Vacuum the shelves before putting them back. For large libraries or valuable collections, visit your nearest Orkida branch with a photo or a sample and we will point you to the right product.
Products from the Orkida Store
We start with cleaning and removing the source, and use residual treatment for cracks only and away from exposed food. We advise following the label dose and the safety interval.
- K-Othrine Partix insecticide for bed bugs, ants, cockroaches, and beetles, 1 L: K-Othrine Partix (deltamethrin) is a residual spray for cracks, empty shelves, and corners where beetles gather, used away from exposed food.
- K-Othrine 0.05 DP for cockroaches, ants, and scorpions, 1 kg: K-Othrine dust for closed voids behind shelves and walls and places the spray does not reach.
- American Catch Master ready-to-use glue trap for rats and crawling insects, 72 boards: Glue traps for monitoring, which reveal the beetle species and activity and track the result of treatment.
Frequently Asked Questions
How do I tell drugstore beetles from cigarette beetles?
The cigarette beetle is smooth with no lines, and the drugstore beetle has lined wing covers. Treatment is almost the same.
Is infested food dangerous?
It does not cause known diseases by itself, but it spoils the taste and contaminates the food, so it is preferable to throw it away.
Why do they come back after cleaning?
There may be a hidden infested package or larvae in the shelf cracks, so check the whole pantry.
Do they eat medicines?
They may feed on dry medicines and herbal preparations, so store them tightly sealed.
Does freezing kill all stages?
Freezing for a sufficient period kills almost all stages, and it is advised to keep the food in a sealed package during freezing to avoid moisture.
Can I use dry foods after freezing?
If there are not many larvae and visible droppings, they can be used, but it is better to discard heavily infested foods.
Image credit: Siga, Wikimedia Commons (CC BY-SA 3.0)