Earwigs

Earwigs are omnivorous, they feed on other small invertebrates and plant material. They can reduce fruit aphid problems but they may feed on flowers and leaves of clematis, dahlia, chrysanthemums and occasionally other plants.

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Earwigs and the damage causes to a cosmos flower. Credit: RHS/Entomology.

Quick facts

Common name Common earwig
Scientific name Forficula auricularia
Plants affected Mainly dahlia, clematis and chrysanthemum
Main symptoms Young leaves and flower petals are eaten. Earwigs present on the plants after dark
Most active May-September

What are earwigs?

The common European earwig is a brown insect, it is up to 13-15 mm long (about ½in), and has a pair of distinctive pincers or forceps on their rear end.

There have been several other species of earwig found in Britain only one of these is widespread but only occasionally seen the lesser earwig, Labia minor. It is half the size of the common earwig (about 6mm). It can be found in compost heaps and does not damage plants.  Further information on this species can be found at the Orthoptera and allied insects webpage
 

 

Symptoms

  • Earwigs can be beneficial on fruit trees where they eat aphids
  • Flower petals and young leaves can be eaten; older foliage is sometimes reduced to a tattered network of veins
  • Inspect plants by torchlight on a mild night to find earwigs feeding on the flowers and foliage 
  • Earwigs hide in sheltered places during the day and emerge after dark to feed
  • Other nocturnal animals that might be responsible for similar damage are slugs, snails or caterpillars

Control of fruit aphids

On fruit trees earwigs can give good control of fruit aphids and do not cause damage to the trees or fruit. Providing shelters such as flower pots loosely stuffed with hay in trees can help increase numbers.

Control

On fruit trees earwigs should be encouraged as they are useful predators of fruit aphids.

Check susceptible plants frequently from spring onwards so action can be taken before a damaging population has developed. When choosing control options you can minimise harm to non-target animals by starting with the methods in the non-pesticide control section. If this is not sufficient to reduce the damage to acceptable levels then you may choose to use pesticides. Within this group the shorter persistence pesticides (that are usually certified for organic growing) are likely to be less damaging to non-target wildlife than those with longer persistence and/or systemic action.

Non-pesticide controls

  • Where possible tolerate earwigs in the garden, they are part of the natural balance and in some cases, especially fruit trees and shrubs can help reduce aphid numbers
  • Trap earwigs by placing upturned flower pots loosely stuffed with hay or straw on canes among plants being attacked (This can also provide useful shelter when encouraging earwigs in fruit trees). Every morning shake out the pots and remove the earwigs (Do not do this if encouraging earwigs in fruit trees) This may not protect plants when earwigs are abundant, but it is a useful means of monitoring their numbers

Pesticide control

The RHS believes that avoiding pests, diseases and weeds by good practice in cultivation methods, cultivar selection, garden hygiene and encouraging or introducing natural enemies, should be the first line of control. If chemical controls are used, they should be used only in a minimal and highly targeted manner.

Before resorting to pesticides remember that earwigs are omnivores and can be of benefit in the garden by eating some other invertebrates.

  • Organic contact insecticides containing natural pyrethrinrum (e.g. Bug Clear Gun for Fruit & Veg, Neudorff Bug Free Bug and Larvae Killer). Several applications of this short persistence products may be necessary to give good control
  • More persistent contact-action insecticides include the synthetic pyrethroids lambda-cyhalothrin (e.g. Westland Resolva Bug Killer), deltamethrin (e.g. Provanto Ultimate Fruit & Vegetable Bug Killer, Provanto Sprayday Greenfly Killer) and cypermethrin (e.g. Py Bug Killer)
  • A systemic containing the active ingredient Flupyradifurone (Provanto Smart Bug Killer) is available for use on ornamentals and selected edibles
  • The systemic neonicotinoid insecticide acetamiprid (e.g. Bug Clear Ultra) is also available

Follow label instructions when using pesticides. On edible plants make sure the food plant is listed on the label and follow instructions on maximum number of applications, spray interval and harvest interval. Plants in flower should not be sprayed due to the danger to bees and other pollinating insects. Inclusion of a pesticide product does not indicate a recommendation or endorsement by RHS Gardening Advice. It is a list of products currently available to the home gardener.

Downloads

Pesticides for gardeners (pdf document)
 
 
 
 

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 nymphs look like smaller versions of the adult insect 
  • Earwigs are one of the few insects where the adults show some parental care, protecting the eggs and nymphs from predators and fungal infections
  • Female earwigs usually have straight pincers at the rear end, whilst those of males are curved. The pincers are harmless although they may be raised in self defence
  • Earwigs are largely nocturnal, coming out to feed at night during late spring to early autumn and prefer soft tissues to older foliage
  • Earwigs also feed on aphids and some other invertebrates and can help reduce infestations particularly in fruit trees

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