Tiny insects running around a food cupboard can be alarming, especially when they appear among flour, cereals or other stored goods.
Booklice are common, and finding them does not automatically mean your home needs insecticide treatment.
Booklice are also known as psocids. Despite the name, they are not true lice and do not bite people.
What do booklice look like?
Booklice are very small, usually around 1 to 2 mm long. They have soft, flattened bodies, long antennae and are usually pale cream, grey or light brown. The insects commonly found indoors are generally wingless.
Because they are so small, they can be difficult to identify. A clear close-up photograph may help distinguish them from other insects found in cupboards.
Biology and life cycle
Booklice develop from eggs into nymphs, which look like smaller versions of the adults. The nymphs grow through a series of moults before becoming adults. Warm, damp conditions can help them develop and reproduce more quickly.
Booklice feed mainly on moulds and other microscopic growth. This can occur around damp food, paper, cardboard, book bindings and other materials. Flour, cereals and similar stored goods can provide suitable conditions if they become damp.
Why have I found booklice in my food cupboard?
Booklice may be brought into the home with food, packaging or other stored goods. They can then increase in number if there is moisture in the cupboard or in the products stored there.
Their presence is not, by itself, proof of poor housekeeping. Condensation, a small leak or dampness in a cupboard can create conditions for mould and microscopic growth, which booklice feed on.
Are booklice harmful?
Booklice do not bite or sting people and are not known to spread disease. They can contaminate stored food, so discard any affected products, especially if they are damp or show signs of mould.
Seeing them in numbers can be upsetting, but spraying the cupboard is unlikely to deal with the reason they are there.
What should I do if I find booklice?
Check the food and packaging in the affected cupboard. Discard products that contain insects or are damp or mouldy. Vacuum the cupboard carefully, including corners, shelf joints and cracks, then empty the vacuum cleaner.
Avoid washing the area with lots of water. This can add moisture and prolong the conditions booklice need. If the cupboard needs cleaning, use as little moisture as possible and let it dry fully.
Check for condensation, damp patches or leaks. Keep the cupboard dry, improve airflow where possible and store replacement flour, cereals and other dry goods in airtight containers.
How can booklice be controlled?
The main step is to remove the damp conditions that allow booklice and the mould they feed on to persist. A dehumidifier may help if the surrounding area is humid. Any leak or other source of dampness should be dealt with.
Vacuuming removes visible insects. Once affected goods are removed and the area is dry, booklice are much less likely to persist.
Guardian does not recommend insecticide treatment for booklice. Spraying does not address the moisture that is allowing them to survive, and a water-based treatment could add moisture to the area.
When should I contact a pest professional?
If booklice keep appearing after you have removed affected goods, vacuumed and dried the area, there may be an ongoing source of moisture or the insects may have been misidentified.
Guardian can help identify what you have found and advise on the most sensible next step. For booklice, this is usually checking for dampness and drying the area rather than applying insecticide.
Contact Guardian Pest Control
Tell us where you have found the insects and what they look like. A clear photograph may help us identify them.
