By Chris Williams on May 24, 2018.

Domestic cockroaches are those that live and reproduce inside homes or other structures. The very common German cockroach is the best known, but American cockroaches and Oriental cockroaches will sometimes reproduce inside.

One cockroach that is not a domestic cockroach but causes great alarm when it appears indoors is the wood cockroach. It doesn’t reproduce inside though and it usually doesn’t survive long in drier indoor air (see Wood Cockroaches Are Only Temporary). Male wood roaches fly and are more active at night, while females usually remain hidden.


There are 12 different species of Parcoblatta wood cockroaches. In our northeast region, Parcoblatta pennsylvanica, also known as the Pennsylvania wood cockroach, is the most common.

The male Pennsylvania wood cockroach looks more like a regular cockroach than the female does. He is medium-brown, about an inch long, with long antennae. The long wings that cover his back have a pale margin around the edges. He uses those wings to fly to lights at night. The female is smaller and darker in color with only very short wings that don’t cover her abdomen. In fact, she can’t fly. She also has a lighter margin along the sides of her wings and thorax.

Wood cockroach nymphs are wingless and a shiny dark brown. Most people wouldn’t even recognize them as cockroaches, maybe thinking they are beetles instead. Since wood cockroaches can also be easily confused with domestic pest roaches that can reproduce indoors, it’s a good idea to have any new cockroach invaders identified.


Wood cockroaches inhabit woods where they are found under bark, in stumps, in hollow trees, or in ground litter or mulch, so it follows that if you have a wooded property, you may at some time be visited by wood roaches. In Massachusetts and New Hampshire, May into June are the months with the most wood cockroach complaints and that’s because of increased activity during their mating season.

Male wood roaches end up inside homes, usually in one of three ways: (1) they are sometimes carried inside in firewood where they are hiding or spending the winter under bark; (2) since they fly to lights at night, in spring they can end up around porch or yard lights, in rain gutters, or even near windows with bright lights inside; (3) if a female wood cockroach has already found her way inside, males may follow her pheromone signals to get inside as well. In these last two cases, keeping wood roaches out may depend on how well sealed your home is. Missing screens or door thresholds, or small openings around foundations or rooflines can provide entry points.

Help prevent wood cockroach invasions by pest-proofing your home (Colonial Pest can do that), managing outdoor lighting, and by keeping wood mulch, leaf litter, and firewood piles away from the house. We can also treat around the outside perimeter of your home to stop cockroaches (and other pests) before they can get inside.

See also: Wood Cockroaches Are Making Their Appearance in Our Area




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