We’ve just turned the corner from spring into summer and that means it’s prime time for wood cockroaches. Now if you don’t have a treed lot or woods around your home, even at a distance, this may not apply to you. You may never have even seen a wood cockroach, or you may have seen one and assumed it was a regular ol’ cockroach that you brought home from the grocery store.

IT’S NOT YOUR TYPICAL INDOOR COCKROACH

But if like many of us, your property has trees, stumps, heavy wood mulch, or lots of ground debris, you may be very familiar with the Pennsylvania wood cockroach, Parcoblatta pennsylvanica. Since this medium-sized cockroach feeds on decaying organic matter, prefers damp areas, and nests in rotting wood, it is associated with trees and tree litter. It is not known as an indoor cockroach and, in fact, does not survive long inside, except in very damp conditions. Nevertheless, it gets into homes often enough to be considered a seasonal pest.

Wood cockroaches are active at this time of year. Around homes, these roaches can be found in firewood, mulch, in stumps or hollow trees, under cedar shake shingles, in potted plants, and in roof gutters. You may see any stage of this roach outside your home, but are most likely to see the winged males inside. This is mating season for these cockroaches and the males are attracted to lights and female pheromones. 

MALE AND FEMALE ROACHES LOOK VERY DIFFERENT

Female Parcoblatta pennsylvanica wood roach. Note the short wings.

The winged male wood cockroach is about one inch long, light to dark brown with a pale yellow edge around the body. The female is smaller and wider, about ½ inch long, dark brown, with short, non-functional wings. The wingless nymphs are shiny, reddish-brown.

Wood roaches can be carried indoors on firewood or plant pots, but they often enter around doors or windows after being drawn there by a combination of bright outside lights and mating pheromones. It’s not that they necessarily want to be in your home, they just found a convenient opening. Females crawl in and go into hiding once indoors and male roaches are quiet during the day but may fly to indoor lights at night.

KEEPING WOOD ROACHES OUT IS JOB ONE

Since these cockroaches are not year-round, reproducing indoor pests like some other cockroaches, seasonal control of wood roaches is a prevention issue and can be an outdoor job. Efforts should be directed at keeping them out with pest-proofing or sealing of entry points, light reduction (see Porch Lights Attracting Bugs? Choose a Better Bulb), and often insecticide treatment around windows, doors, and other entry points.

Colonial Pest can help with wood cockroach control. Customers enrolled in our Preventative Maintenance Program automatically receive a twice a year exterior treatment directed at pests around foundations, and that includes wood cockroaches. 

For more on wood cockroaches and their control, see:

• Late Spring is When Wood Cockroaches Appear
• How to Keep Wood Roaches Out of Your Home
• Wood Cockroaches Are Only Temporary