What Are Booklice and How to Get Rid of Them?

The short answer: Booklice are tiny (1–2 mm) pale insects that feed on mould and starch, they are not true lice and don’t bite. They appear in damp, humid environments (humidity >60%). The simplest control: reduce humidity below 50%, they will dehydrate and die. Also remove mouldy paper, cardboard, and damp clutter. They are harmless but annoying.

1. Confirm it’s booklice

• Size 1–2 mm, pale yellowish-white or greyish, soft-bodied, no wings.
• Long thread-like antennae, they crawl fairly fast.
• Often found on damp walls, in old books, behind wallpaper, and in cardboard boxes.
• They are not lice, they belong to a different order (Psocoptera).

2. Where do they come from?

• They thrive in high humidity, new renovations with damp wallpaper, basements, and bathrooms are common.
• They feed on mould spores and starchy glues, book bindings, wallpaper paste, cardboard adhesives.
• They can be introduced with infested cardboard, books, or furniture.

3. Step 1: reduce humidity (the golden rule)

• Use a dehumidifier to bring indoor relative humidity below 50%, at this level, booklice cannot survive.
• Ventilate rooms, open windows or use exhaust fans.
• Fix leaks and dry out wet areas.
• I’ve seen booklice vanish within 3–4 days of consistent dehumidification.

4. Step 2: remove mould and food sources

• Wipe down walls, shelves, and baseboards with a damp cloth to remove mould.
• Throw away damp cardboard boxes, old newspapers, and mouldy paper, these are their main food.
• Store books in dry, ventilated places, use silica gel packs in bookcases.
• Clean behind furniture and in cupboards to eliminate dust and mould.

5. Step 3: seal cracks and clean

• Caulk cracks in walls and baseboards to remove hiding places.
• Vacuum corners and crevices to remove eggs and adults.
• Use a HEPA vacuum to trap allergens from mould spores.

6. Step 4: chemical control (rarely needed)

• Since they die from dryness alone, insecticides are usually unnecessary.
• However, if you have a persistent problem, you can spray dinotefuran-containing insecticide along baseboards and in wall voids, but it’s overkill if humidity is controlled.

7. Long-term prevention

• Keep your home well-ventilated and dry.
• Regularly inspect areas prone to moisture, under sinks, around windows, and in basements.
• Use a hygrometer to monitor humidity, target 40–50%.

Common mistakes

• ❌ Using insecticides without reducing humidity, they will come back.
• ❌ Ignoring mould, it’s their primary food; remove it.
• ❌ Storing items in damp basements, dry them out or relocate.

Mini FAQ

Q: Do booklice damage books?

A: They can feed on the paste and mould on book bindings, but they don’t eat paper fibres like silverfish do.

Q: Can booklice live on humans?

A: No, they are not parasitic; they need fungi and high humidity.

Q: How do I know if my humidity is too high?

A: Use a hygrometer; if it reads above 60%, you’re at risk.

Your booklice control list

• Measure humidity, aim <50%.
• Run dehumidifier and fans.
• Remove damp cardboard, paper, and mouldy items.
• Wipe down shelves with vinegar solution.
• Seal cracks and vacuum.
• Monitor humidity weekly, prevention is simple.