Relying on moist conditions, spotting woodlice in the open is uncommon in the summer, and are typically found throughout the other three seasons. Any woodlice living without damp conditions may often die from dehydration, so they’ll rarely enter homes without damp conditions encouraging them inside. They feed on leaves, rotting wood and mould, so taking moisture out of the mix impacts their food sources. You can typically find them in the garden hiding underneath plant pots.

There are three main species of woodlouse, with about 30 in total living in the UK; the Common Wood Louse (Oniscus asellus) being the largest, growing to a length of up to 15mm. They are one of the few types of land-based crustaceans; to the eye they appear to wear grey/black armour, and some species when feeling threatened will curl up into a ball for protection.

Woodlice aren’t a risk to health and whilst contained in the garden, are useful in helping break down garden waste, particularly in compost bins. You’ll want to stop them from entering your home however and doing internal damage.

Signs of infestation

Other than seeing physical woodlice bodies, an immediate warning sign of an infestation within the home are small, oval or round holes in wooden surfaces and furniture. You may also notice bore dust and crumbling wood.

Prevention

Woodlice gain entry to homes through small cracks and crevices. If you spot signs of woodlouse activity, check for holes in walls or broken seals around doors and windows and repair these. A common place for them to reside is underneath pots or planters so keep these away from the walls of your home to prevent accidental wandering. You may also want to reconsider any vegetation right outside your home as this may also harbour woodlice.

Clean guttering regularly to avoid build-up of plant matter which may encourage infestations.

Resolve any areas of damp or mould within your home as this will limit the appeal of infestation.

Treatment

As they don’t pose any health risks, you may prefer to sweep up any live woodlice that you see and deposit them outside, away from the home where they might be encouraged back inside.

If your home has areas of damp that have attracted woodlice, improve the ventilation or increase the heating to dry these areas out.

For a dry treatment in the home, you may prefer to use chemical powders, such as the Defenders Ant Killer Powder or Zero In Ant & Crawling Insect Killer Powder; although labelled for ants, they’re effective on other crawling insects too, like woodlice. You may find these preferable for use near electrical supplies, where water-based treatments aren’t advisable. These powders can also be used outside, and won’t affect plant growth.

There’s also immediate knockdown insect killers in Zero In, including Total Insect Killer in both an aerosol spray and water-based spray. The Zero In Ultra Power Natural Insect Killer Bomb is a one-shot aerosol that kills a variety of insect pests inside the home, including flies, fleas, bed bugs and woodlice.