Colour - Creamy brown to Black.
Body - Long and flattened. 12-25 mm long.
Wings - Folded in small covers.
Mouthparts - chewing.
Antennae - Short, with raised rings or bands (annulate), many segments.
Legs - short, similar length. Foot section (Tarsi) has 3 segments.
Head - Broad. Flattened. Moves on cylindrical, unprotected neck.
Thorax - about one quarter of length. Segments free.
Abdomen - Large curved claws on tail. Males and females have different shaped claws. Thorax is telescopic, long, and freely movable with 8-10 segments. Slightly flattened. Widest in the middle (i.e. slightly oval shaped).
Most active at night. Favour damp confined spaces.
Egg - Oval. <2 mm. Semitransparent. Creamy white. Smooth.
Nymph - Resemble adults. Lighter colour. Shorter antennae. Straighter claws.
Habits - Favour dark moist places; bark of trees and under debris or windrows. May fly at night for short distances. Attracted to lights. Omnivorous.
Eggs laid in a batch (15-80 eggs) often at the bottom of a short burrow. The female licks the eggs to reduce fungal attack. They hatch 2-3 weeks later. The female usually looks after the young nymphs initially but may cannibalise them later. The young moult 4-5 times which may take 40-100 days.
Habitats:Origin and History:
New infestation in WA have been associated with caravan parks. It is assumed that the earwigs probably sheltered in folded canvas awnings (a favourite earwig hide out) and were transported here from other states.
They fly short distances. Long range dispersal, of over a kilometre or two, appears to require the assistance of man.
Significance:Forficula auricularia may built up to very large numbers and become a nuisance pest. In W.A. it has delayed harvesting of windrowed crops and caused unacceptable moisture levels in stored grain. Canola pods can be damaged in swathed crops. Mature canola has been damaged by chewing. Seedling canola has been killed, especially on areas with retained stubble and header trails from the previous crop. They may eat holes in leafy vegetables or increase damage to fruit. They eat flower buds and may chew carpets and clothing.
Management and Control:In most years control is not economical. Insecticides, such as carbaryl and chlorpyrifos can provide control provided application timing and equipment are adjusted to ensure the pest receives a reasonable dose. This is often difficult because the earwigs shelter under debris during the day.
Baiting seems to be the most successful method of control. It is applied in spring in orchards; however other times of the year may be appropriate for winter crops. This is bait made by
1) Mix 200 mL Lorsban EC with 250 mL Sunflower oil
2) Mix this with 5 kg of cracked wheat or cracked sorghum
3) Allow to stand for 2-3 hours
4) Broadcast 5 kg/ha of this mix onto the infested area (with a fertiliser spreader).
5) Use gloves when making and handling this bait.
Burning debris and old windrows has given some reduction numbers.
In garden situations a trap can be made by filling a pot with crumpled newspaper or straw and leaving it upturned in the garden overnight. Earwigs will shelter in the pot and can be disposed of the next day.
Related Species:There are over 60 species of earwigs in Australia and most of them cause no damage.
Similar Species:European earwigs usually have light yellow legs and pincers, with a dark brown body and yellow stripes on its 'shoulders' and distinctive tail pincers. Most native earwigs have dark legs and pincers with reddish brown or almost black bodies and no yellow stripes.
References:CSIRO. The Insects of Australia. Melbourne University Press. (1991) p360.
Jones, D. & Elliot, R. Pests Diseases and Ailments of Australian Plants. Lothian Publishing Co. p160.
Collated by HerbiGuide. Phone 08 98444064 or www.herbiguide.com.au for more information.