The Asian cockroach is a relative newcomer to the United States, making its debut here only in the mid-1980’s. When they were first discovered, the pest control worker collecting them simply assumed them to be German cockroaches. Which when you see them is no surprise.
Because Asian cockroaches look nearly identical to German roaches. In fact, it originally took specialized testing for researchers to realize they were dealing with something new.
These tricksters aren’t your typical home invaders. They might look just like their German relatives but their behavior reveals stark differences.
Keep reading to find out more about these differences, learn about the Asian cockroach’s behavior and discover tips for keeping your home safe from these unusual little pests.
How to Identify an Asian Cockroach
Asian cockroaches (Blattella asahinai) look so much like German cockroaches (Blattella germanica) that even a professional will be hard-pressed to tell the difference. Both species are small and brown-colored. Both have wings and dark bands running down from their heads along their backs.
The details that distinguish the two species are fine: If you look very closely (much more closely than a living cockroach will let you) you can see that the border of an Asian cockroach’s abdomen is white while that of a German roach is colored.
Where Do Asian Cockroaches Live?
The first U.S. Asian roaches were discovered in 1986 in Lakeland Florida, most likely having hitched a ride here in goods imported from Japan. By then, they’d already built up a significant population and spread across the state. Since then, the species has expanded to other states, massing in huge populations in many outdoor areas.
They’re most prevalent in southern states, including Florida, Alabama, Georgia, South Carolina and Texas. In some areas around Tampa, FL, these cockroaches live in incredibly dense groups–as many as 250,000 per acre!
The Asian cockroach is an outdoor species that most commonly lives in shaded areas. They especially like living in mulch and grass, where their numbers can rise into the ten thousands. They’ll also infest compost piles and feed on the organic material inside.
Asian cockroaches rarely invade homes and other buildings. However, since they’re attracted to lights, they sometimes fly through open windows and doors to land on the lights and television screens inside. These cockroaches aren’t the ruthless home invaders that German roaches can be, but there’s still a risk that they’ll multiply rapidly once they’ve come indoors.
The Life Cycle of Asian Cockroaches
An average female Asian roach lays 4 egg cases over its lifetime with several dozen eggs in each. Asian cockroach nymphs are smaller than German nymphs; their egg cases are smaller, too. Their life spans are relatively short–only between 100 and 175 days.
Asian cockroaches are fairly seasonal. You can expect to see larger populations of adults in the spring and late summer. Nymph populations are at their peak during the summer months as they grow and molt.
Will You Come into Contact with Asian Cockroaches?
Asian roaches are nocturnal and become most active just after the sun sets. They’re quick to fly around outdoors and indoors. While they’re flying, you might mistake them for moths because of their size. Meanwhile, their “twins,” the German roaches, can’t fly very well at all.
Asian cockroaches have a strong attraction to every kind of light and even fly toward lightly colored surfaces. When they enter homes they’ll land on lamps, TVs, porch lights and more. These roaches are so strongly attracted to lights that they’ll fly from room to room as the lights are turned off in one and on in another.
Asian roaches can fly as far as 120 feet at a time. It can be pretty startling to see groups of them fly away at the same time. You might disturb a large number of them when tending to landscaping or mowing the lawn and, suddenly, find yourself surrounded by flying bugs. Don’t panic!
Luckily, Asian cockroaches won’t bite. They’re almost certainly flying away from you because you’re a dangerous threat. Of course, these flying cockroaches can still be frightening, especially in places where they gather in the thousands!
Asian Cockroaches Are Dangerous Pests
Though they’re less likely than other cockroach species to invade your house and become a huge problem, they’re still dangerous pests to have hanging around your property. Asian cockroaches have a similar diet to their relatives–that means garbage, decomposing waste and other unpleasant things.
Their unsavory diet leads them to pick up all kinds of bacteria that they could potentially carry into your home. Even outside, they’ll contaminate any surfaces they touch, including garage equipment, countertops and gardening tools.
Asian cockroaches have also become a threat to lettuce producers in Florida. Though they don’t eat lettuce, their huge numbers can force many crops to be discarded when cockroaches (living or dead) are found in them.
How to Get Rid of Asian Cockroaches
Asian cockroaches are tricky pests to control. It’s difficult to target them with pesticide sprays or baits because they can spread across large areas of land.
Their tendency to fly into houses (instead of climbing in through holes or cracks) also means standard perimeter sprays won’t work. These bugs go after the lights–especially bright white lights and yellow incandescent bulbs–and don’t enter through any specific pathways that can be blocked.
The most effective methods of controlling Asian cockroaches include bait in the form of pellets because it can be spread widely outdoors, covering gardens and lawns. Controlling a large population will be a long-term battle involving regular applications of the bait and careful monitoring of how the cockroaches respond.
If you have concerns about Asian cockroaches around your home, it’s probably best to call a pest control professional. They’ll be able to assess the problem and decide how to treat it going forward.
Tips for Preventing Asian Cockroaches in Your Home
Preventing Asian roaches mainly involves keeping the area around your house tidy and unattractive to these insects. By removing damp piles of leaves and keeping grass short, you can take away some of these insects’ potential habitats.
Researchers have found that oak leaf litter and rubber mulch are especially attractive to Asian cockroaches. Clearing litter and choosing another type of mulch could be effective parts of your cockroach-prevention plan.
Comprehensive cockroach control involves keeping the inside of your home clean, too. Dirty dishes and crumbs can provide easy sources of food for cockroaches and other pests. Though Asian roaches typically stay outside, you’ve already discovered that they’ll fly into houses when lights are on. You don’t want them to take a liking to your home once they’re inside.
Wash dishes and wipe counters each night to remove spills, crumbs and cooking leftovers that could attract pests. Change garbage bags as soon as they’re full to remove strong smells. Don’t forget to sweep and vacuum your floors, too.
It’s important to keep storage areas organized so pests have fewer places to hide. Practicing good cleaning habits and keeping a tidy home and garage are good general pest prevention tips that apply to Asian cockroaches and other roach species.
Asian cockroaches are primarily outdoor pests that can multiply into huge populations in grassy areas and gardens. They’re unwelcome insects and difficult to control, especially once they’ve established themselves as the primary pest in the area. But with a strategic plan (and, in some circumstances, help from a professional) you can keep these cockroaches away from your home.
Frequently Asked Questions
Yes, Asian cockroaches have fully formed wings that enable them to fly long distances. Their ability to fly lets them spread out quickly across fields and lawns, forming large populations. You might be startled by a group of them flying away if you’ve started mowing the lawn or sprayed the garden mulch with a hose. Don’t worry; they’re more scared of you and won’t stick around.
Yes, Asian cockroaches are strong fliers. Unlike German cockroaches which rarely fly, and American cockroaches which simply glide, these pests can fly over 100 feet at a time. Sometimes, they fly into homes and buildings toward light bulbs, TV screens and other light sources.
Asian cockroaches don’t bite humans (or pets). They’re quick to fly away from people and other animals. Indoors, it might appear that these flying roaches are following you from room to room. In fact, they’re simply following the lights–as you leave one room and turn off the lights, they’ll fly to the next room’s lamps and ceiling lights.
1. Richman, Dina L. (2017) Asian Cockroach, Blattella asahinai Mizukubo. IFAS Extension. Retrieved from https://edis.ifas.ufl.edu/in277
2. Retrieved from https://urbanentomology.tamu.edu/cockroaches/asian-cockroach/
3. Williams, Larry (2013) Asian Cockroach – Is it a Pest of the Home or the Garden? IFAS Extension. Retrieved from http://nwdistrict.ifas.ufl.edu/hort/2013/08/12/asian-cockroach-is-it-a-pest-of-the-home
4. Trap Assisted Scouting for Asian Cockroach Management. (2018)
5. Snoddy, Edward T. and Arthur G. Appel (2013) Mulch Preferences of the Asian Cockroach. Journal of Economic Entomology. Retrieved from https://doi.org/10.1603/EC12032