Earwigs

What are earwigs?

Earwigs are yellowish brown insects, up to 13-15 mm long (about ½in), that have a pair of distinctive pincers or forceps on their rear end.

Symptoms

• Flower petals and young leaves are eaten; older foliage is reduced to a tattered network of veins
• Inspect plants by torchlight on a mild night to find earwigs feeding on the flowers and foliage 
• Other nocturnal pests that could be responsible are slugs, snails or caterpillars

Control

Prevention

• Earwigs hide in sheltered places during the day and emerge to feed after dark
• Avoid growing susceptible plants against wooden fences, which provide daytime hiding places

Non-chemical control

• Trap earwigs by placing upturned flower pots loosely stuffed with hay or straw on canes among plants being attacked
• Every morning shake out the pots and remove the earwigs
• This may not protect plants when earwigs are abundant, but it is a useful means of monitoring their numbers

Chemical control

• Before resorting to chemicals remember that earwigs are omnivores and can be of benefit in the garden by eating small insect pests and their eggs
• If damage is extensive, spray at dusk on mild evenings when earwigs are likely to be active with deltamethrin (Bayer Sprayday Greenfly Killer) or lambda-cyhalothrin (Westland Plant Rescue Fruit & Vegetable Bug Killer)

Download

Pesticides for gardeners (Adobe Acrobat pdf document outlining pesticides available to gardeners)

Biology

Earwigs overwinter as adult insects in the soil and other sheltered places.

• Batches of eggs are laid in the soil in midwinter and again in early summer
• Female earwigs remain with their eggs until they have hatched
• The immature nymphs are smaller versions of the adult insect 
• Earwigs come out to feed at night during late spring to early autumn, and prefer soft tissues to older foliage
• They can eat small insects and eggs, as well as plant material