Earwigs
Also known as European earwig, Common earwig, Forficula auricularia
In short
Earwigs are night-active insects with pincers at the tail. They eat both plants and small insects: they can rag the petals of dahlias and other flowers and damage seedlings, but they also eat aphids and insect eggs and are useful predators on fruit trees.
How it looks
Elongated, flattened, reddish-brown insects about 2 cm (3/4 inch) long with a pair of forceps-like pincers (cerci) at the end of the body; males have curved pincers, females straighter ones. Short, hard wing covers hide folded wings, but they rarely fly. Nymphs look like small, paler, wingless adults. By day they hide in tight, dark, moist places — under pots, in rolled leaves, flower heads and debris.
Signs
Ragged, irregular holes in leaves and petals, often at night; flower petals eaten (dahlias, chrysanthemums, clematis, zinnias, marigolds); seedlings chewed; shallow gouges in soft fruit. Earwigs found hiding in flowers or under pots in the morning.
Life cycle
In autumn and winter, females lay masses of 30 or more eggs in a soil chamber and guard them and the young nymphs. There is usually one generation a year, though females may produce two broods.
What favours it
Dark, cool, moist hiding places such as mulch, ivy, weeds, debris and stacked pots near plants.
Prevention
- Reduce hiding places close to vulnerable plants: clear debris and dense weeds.
- Check flowers and seedlings at night to confirm earwigs are the cause before acting.
Treatment
Start with the first step and move down only if the problem persists.
- Tolerate them where damage is light, especially on fruit trees where they eat aphids.
- Trap them: place upturned pots loosely stuffed with straw on canes, rolled damp newspaper or short bamboo tubes near plants, and empty them each morning away from the plants you want to protect.
- Use sticky bands on stems or trunks to stop them climbing.
- If damage is severe, baits containing spinosad can be used, though baits often work poorly where other food is plentiful — follow the product label.
Pros and cons
Pros
- Eat aphids, insect eggs and other small soft-bodied insects; can give useful aphid control on fruit trees.
Cons
- Damage petals, young leaves, seedlings and soft fruit.
Look-alikes
- Rove beetles
- Also have short wing covers and a long body, but lack the tail pincers and are mainly predators.
- Slugs and snails
- Leave slime trails and smooth-edged holes.
Affected plants
Dahlias, chrysanthemums, clematis, zinnias, marigolds, seedlings, soft fruit and sweetcorn silks.
Related
Sources
Written in our own words from these sources. Check a product label before using any treatment.