On this page
How to identify it
- Adult males grow to about 1 inch, with longer, thinner abdomens and long wings covering the abdomen; males fly well.[1][4][3]
- Females have wider abdomens and short, non-functional wings that often leave the abdomen tip exposed (see below on size).[1][4]
- They are light brown to nearly black. Adults and large nymphs often have a pale, creamy or clear edge on the shield behind the head, and in some species the pale edge runs onto the outer margin of the front wings.[1][2][4][3]
- Inside a house they behave differently from pest roaches: they are active by day as well as at night, don't hurry out of sight when approached, and wander around rather than gathering in one spot.[2]
- Twelve Parcoblatta species occur in North America, seven of them in Pennsylvania; only adult males can reliably be identified to species, but all have similar habits.[1][5]
Look-alikes
| Look-alike | How to tell them apart |
|---|---|
| American cockroach | Much larger, up to 2 inches, and reddish brown; Iowa State notes the wood roach is slightly smaller with a similar flat, oval shape.[1][2] |
| Oriental cockroach | Dark brown to nearly black; females lack wings and males have short wings like female wood cockroaches. Minnesota notes the Oriental cockroach lacks the light bands near the head.[1][4] |
Where it lives
Native across North America in wooded areas with leaf litter and rotting logs.[1]
Biology and life cycle
Egg cases are laid in summer and hatch in about a month; nymphs overwinter and mature the next spring, sometimes taking up to two years. Adults can also live up to two years.[1]
They live under loose bark, in rotting logs, woodpiles, dead trees and leaf litter and under stones, and feed on decaying plant matter as decomposers.[1][3][4]
They can be very abundant in southeastern pine forests, where the broad wood cockroach makes up more than half the biomass in the diet of the endangered red-cockaded woodpecker.[5]
Males fly to lights at night in rural areas; Iowa State puts their flights in late May through June. Large numbers sometimes collect in clogged rain gutters and crawl spaces.[1][2][3]
Damage and signs
- Not considered pests: they get in through foundation cracks and gaps around doors and windows, on firewood, or after being drawn to porch lights, and they don't harm the house, furnishings or the people in it.[1][2][3]
- Homes with cedar shake shingles in wooded areas sometimes have wood cockroaches living under the shingles, which mimic their natural habitat.[1]
Health risk
They don't feed or reproduce indoors and die within a few days from dehydration; Iowa State calls their presence indoors strictly a temporary annoyance.[1][2]
Control
Prevention
For roaches living under cedar shakes, Penn State says replacing the roofing or trimming trees to let in sun and dry the roof may be the only long-term fix.[1]
Keep them out
Caulk foundation cracks and gaps around doors and windows, keep screens tight-fitting, add door sweeps, and seal openings where pipes and wires pass through walls.[1][3][2]
Sanitation
Bring in only as much firewood as you'll burn in a few hours, move woodpiles and debris away from the house, remove decayed and fallen logs close to the building, and turn off porch lights at night.[1][2][4]
Traps and physical control
An occasional wood cockroach indoors can simply be picked up and removed.[4]
Pesticides
Sprays and dusts that work on household cockroaches do little against wood roaches. Iowa State calls an outdoor barrier treatment around doors, windows and the foundation a last resort and says spraying firewood does no good.[2]
Where sources disagree
Female size: Penn State says females grow to about 3/4 inch, while Minnesota gives about 1/2 inch for the Pennsylvania wood cockroach. Iowa State gives 3/4 to 1 1/4 inches for wood roaches in general.[1][4][2]
Attraction to lights: Penn State and Minnesota describe flying males coming to lights, while Kentucky says both sexes are attracted to lights.[1][4][3]
Insecticides: Minnesota suggests treating the outside of the building around doors and windows with a residual insecticide when larger numbers are getting in, while Iowa State says such barrier treatments are a last resort and of very limited benefit.[4][2]
Family: Penn State Extension and GBIF place wood cockroaches (Parcoblatta) in the family Ectobiidae, while iNaturalist and the ITIS database still list them under Blattellidae.[1][6][8][7]
Common questions
- Do wood cockroaches infest houses?
- No. They wander in by accident, can't survive the dry indoor air, and don't breed indoors.[1][2][3]
- Why do I see wood roaches on warm nights near lights?
- Adult males fly and are drawn to lights at night, especially in rural areas, so turning off porch lights during their flight season helps.[1][2][4]
Sources
- Penn State Extension, “Wood Cockroaches (updated January 19, 2026).” extension.psu.edu/wood-cockroaches (accessed 2026-11-11)
- Iowa State University Extension and Outreach, “Wood Cockroach (Yard and Garden).” yardandgarden.extension.iastate.edu/encyclopedia/wood-cockroach (accessed 2026-11-11)
- University of Kentucky Entomology, “Cockroach Elimination in Homes and Apartments (ENTFACT-614).” entomology.ca.uky.edu/ef614 (accessed 2026-11-11)
- University of Minnesota Extension, “Cockroaches.” extension.umn.edu/household-insects/cockroaches (accessed 2026-11-11)
- Proceedings of the National Academy of Sciences, via PubMed, “Eliyahu et al. (2012), Unusual macrocyclic lactone sex pheromone of Parcoblatta lata, a primary food source of the endangered red-cockaded woodpecker.” pubmed.ncbi.nlm.nih.gov/22184232/ (accessed 2026-11-11)
- Global Biodiversity Information Facility (GBIF), “Parcoblatta Hebard, 1917 (GBIF Backbone Taxonomy).” api.gbif.org/v1/species/1997469 (accessed 2026-11-11)
- Integrated Taxonomic Information System (ITIS), “Parcoblatta Hebard, 1917, TSN 102418.” www.itis.gov/servlet/SingleRpt/SingleRpt?search_topic=TSN&search_value=102418 (accessed 2026-11-11)
- iNaturalist, “Parcoblatta pennsylvanica taxon page (order and family).” www.inaturalist.org/taxa/129141 (accessed 2026-11-11)