Smoky brown cockroach vs Australian cockroach
These two are easy to mix up. Here's how to tell a smoky brown cockroach from an Australian cockroach, and whether either one bites or stings.
Smoky brown cockroach
Periplaneta fuliginosa
Australian cockroach
Periplaneta australasiae
≠The key differences
Smokybrown cockroach is more uniformly dark brown to blackish and usually lacks the pale pronotal and wing-base bands seen in Australian cockroach.
⚖︎Side by side
| Smoky brown cockroach | Australian cockroach | |
|---|---|---|
| To humans | Allergen potential | Allergen carrier |
| Size | About 30-40 mm body length | 25-35 mm body length |
| Colours | Dark brown, Chestnut brown, Tan (nymphs) | Reddish brown, Dark brown, Pale yellow, Greenish band (appears olive) |
| Family | Blattidae | Blattidae |
| Habitat | Prefers moist outdoor habitats: tree cavities, leaf litter, mulch, compost, storm drains; enters buildings seeking moisture and shelter | Warm, humid environments: leaf litter, mulch, compost, greenhouses, sewers, and buildings (especially kitchens, basements and boiler rooms). |
| Range | Native to East Asia; now established in warm temperate and subtropical regions worldwide, including the southeastern United States, Hawaii, parts of Australia and other warm regions | Probably native to tropical Asia or Africa (not Australia, despite the name); now widespread in tropical and subtropical regions worldwide and established in heated buildings and greenhouses in cooler areas. |
| Active | Nocturnal; active year-round in warm climates and in heated buildings; peak activity at night | Nocturnal; most active at night. Peak activity in warm seasons or year-round in tropical/subtropical areas. |
| Pest? | Yes | Yes |
🔍How to spot a smoky brown cockroach
- Uniformly dark brown to nearly black adult with fully developed wings that extend beyond the abdomen
- Body length about 30-40 mm, flattened oval shape typical of Periplaneta cockroaches
- Attracted to light at night and commonly found around tree cavities, mulch and other moist outdoor sites
- Males are more slender and better fliers than females; nymphs are wingless and lighter in color
🔍How to spot an Australian cockroach
- Reddish-brown body about 25-35 mm long with a pale yellow ring or margin on the pronotum.
- Distinct pale yellow streak along the outer edge of each forewing near the base.
- Long antennae and spiny legs; nymphs are wingless and uniformly darker.
?Frequently asked questions
What is the difference between a smoky brown cockroach and an Australian cockroach?
Smokybrown cockroach is more uniformly dark brown to blackish and usually lacks the pale pronotal and wing-base bands seen in Australian cockroach.
Is a smoky brown cockroach or an Australian cockroach more dangerous?
Smoky brown cockroach: Allergen potential. Australian cockroach: Allergen carrier. Smoky brown cockroaches do not bite or sting as a defensive behavior and are not venomous, but they contaminate food and surfaces with bacteria and allergens; exposure can worsen asthma and allergic reactions. Australian cockroaches are not venomous and do not pose a direct toxic threat, but they can contaminate food and surfaces with bacteria and allergens.
Identification from photos is never certain: don't handle insects you can't identify, and get medical advice for bites, stings or allergic reactions.