Woodworm Life Cycle: Egg, Larva, Pupa, Adult — Explained

The woodworm life cycle has four stages. Almost all of it happens inside the wood, which is why damage stays hidden for years. Understanding the cycle helps you time your checks and your treatment.

Stage 1: egg

In late spring and summer, the female lays eggs on bare timber. She uses cracks, rough end grain and old exit holes. The eggs are tiny, so you will not see them without a lens.

They hatch after a few weeks. The newly hatched grubs bore straight into the wood.

Stage 2: larva

The larva is the woodworm itself. It is creamy white, curved and soft. It spends several years inside the timber, eating as it goes.

This stage causes all the damage. The length depends on the species, the temperature and the wood. Cool, damp wood slows growth, so the stage can last longer. Our guide to woodworm larvae shows what they look like.

Stage 3: pupa

When the larva is fully grown, it moves close to the surface. It builds a small chamber and changes into a pupa. This stage is short, usually a few weeks.

The wood still looks normal from outside, because a thin skin remains. That skin is the last barrier before the beetle leaves.

Stage 4: adult

The adult chews through the skin and leaves a round hole. That hole is the first sign most people see. Adults live for only a few weeks, but they mate and lay the next batch of eggs in that time.

For the common furniture beetle, adults fly mainly from late spring to late summer. You may see them near windows, since they are drawn to light. Read the furniture beetle guide for more.

Why the cycle matters

Because the larval stage is so long, an infestation can run for years before holes appear. The holes you see show damage that began long ago. That is why a survey beats guesswork.

The cycle also explains why timing matters:

• Checks work best from late spring to late summer, when adults emerge.
• Spray protects the surface against emerging adults.
• Paste reaches the larvae deeper in thick wood.

How long does the whole cycle take?

It varies. Warm, damp wood speeds the cycle, while cold, dry wood slows it. For furniture beetle, several years is normal. Other species can take far longer, especially in old oak. See how quickly woodworm spreads for what this means for your home.

What to do with this knowledge

Inspect your timber each spring. If you find fresh dust or holes, check whether the beetle is active using our guide to active versus historic woodworm. Then decide on treatment, or request a survey to be sure.

Where you live matters, because older streets hold more old timber. See our local guides for woodworm treatment in Liverpool and woodworm treatment in Sheffield.

To go deeper, read about the common furniture beetle and the spray treatment, because the right method depends on the beetle.