Earwigs fall into the category of “occasional invaders.” They are outdoor pests that sometimes find their way indoors. When that happens, it’s not always easy to convince your customer that, despite the ominous looking pincers, earwigs are pretty harmless.
Earwigs (order Dermaptera) are found outside in the usual moist areas around foundations: in mulch, under boards, logs, stones, or in potted plants, or heavy ground covers, or leaf or grass piles- where they feed on dead insects or plant material. They usually end up inside when these outdoor hiding places get too dry. Like other foundation pests, they enter around doors and windows and any other openings, but will also climb outside walls. They’re active at night and are attracted to outdoor lights. They are accidentally carried inside in potted plants, firewood, or even in newspapers.
Indoor earwig problems-
When earwigs find their way indoors, they are usually present only in low numbers and insecticide treatment is rarely necessary. They don’t survive long indoors unless it is very damp. Indoors, earwigs feed on food scraps, live or dead insects, mould, or houseplants. Prime indoor hiding places are cracks and crevices near high humidity sites like kitchen, bathroom, and laundry room sinks, in houseplants, stacks of damp newspaper, etc. Concentrate any insecticide treatment near floor level, treating beneath cabinets and around baseboards. Avoid crushing earwigs as they release a disagreeable odour.
Outdoor earwig control-
Earwig control needs to start outside with (a) removal of harbourage sites- remove wood piles, debris, leaf piles, etc., (b) moisture control-rake away mulch to leave a dry zone around the foundation, (c) light management- reduce or shield outside lights, and (d) pest-proofing- add door thresholds. Earwigs can be difficult to control outside with insecticides since they hide during the day in soil, mulch, or cracks and crevices. They also have unique tarsal pads that allow them to walk through insecticide with very little contact. Granular baits though do seem to work well against earwigs when used around foundations. A residual perimeter treatment, including the bottom of siding, can help prevent infestation of the structure.
Earwigs are one of the few insects that exhibit maternal care. The female cleans and moves her 40 or so eggs around in her underground nest so they don’t get mouldy. She guards the eggs from other earwigs and will move them if she feels threatened. She then cares for and feeds the newly hatched young in the nest until they are ready to fend for themselves.