07/24/2025

The Asian Cockroach: a Unique Pest Challenge

By David Moore, II, BCE, Dodson Pest Control

Not everything is what it seems.  Recently, I have been asked to consult on a number of cases of flying German cockroaches that are coming from outside.  I know instantly that is not the case.  A pest that has been growing in numbers over recent years is the Asian cockroach and you can be very easily fooled by this pest if you are not careful.

Though often mistaken for its close relative, the German cockroach, the Asian cockroach poses unique challenges in pest management due to its outdoor habitat, flying ability, and light-attracted behavior. Asian cockroaches are nearly identical in appearance to German cockroaches, which can lead to misidentification. They both look very similar in size, shape, color, and identifying markers on their pronotum.

The best way to distinguish them is through behavior and habitat. Asian cockroaches are strong fliers and are often seen flying into homes through open doors and windows, especially at dusk, while German cockroaches are usually found indoors and do not fly readily.  Additionally, Asian cockroaches are found outdoors in mulch, lawns, and leaf litter, while Germans are found on the interior mostly in kitchens and bathrooms.

Unlike most cockroach species, Asian cockroaches are outdoor dwellers. They prefer moist, shaded environments (mulch, leaf litter, ground cover), areas with abundant organic material, and will fly toward light sources at dusk and night (e.g., porch lights, TV screens, lamps).

This species is primarily nocturnal and becomes active in the evening. Their strong flying ability often causes them to enter homes through open windows, doors, or attic vents, especially when drawn to indoor lights.

While Asian cockroaches are less likely than German cockroaches to establish infestations indoors, they still pose concerns as a nuisance pest. In particular, they are often misidentified as German cockroaches.  In large numbers, their presence can overwhelm residential yards and create an impression of an indoor infestation even if they're mainly coming from outside.

Control of Asian cockroaches can be broken down into some simple steps.  First is outdoor habitat modification.  Talk to the homeowner about reducing their mulch thickness, managing leaf litter in their yard, trimming vegetation, and trying to limit overwatering their lawns.  Second is light management.  Talk to them about limiting light leakage out of the structure and switching to sodium bulbs to reduce the attractiveness of the structure.  Structural exclusion might be necessary as well in some situations.  For chemical controls, repellent insecticides might be necessary to help prevent Asian cockroaches from entering a structure.  Some insecticidal baits might help the situation but remember these are free-flying insects. Insecticidal treatments might not be as effective as preventative measures, which can be applied to the landscaping and structure for control.

The Asian cockroach presents a unique pest challenge due to its outdoor lifestyle and strong attraction to light. Though often mistaken for the German cockroach, its behavior, habitat preference, and flight capability set it apart. Effective management of Asian cockroaches relies heavily on habitat modification, light control, and preventive exclusion measures, with chemical treatments serving as a secondary strategy.