by Cole Sikes/Alabama Electric Cooperative Service
No other animal can seem more supernatural than a centipede. These creatures can be particularly disturbing when they invade your home. An Alabama Cooperative Extension System entomologist aims to educate homeowners about centipedes and control them.
Alien or arthropod?
In Alabama, one of the most troublesome home invaders is the garden millipede, Oxidus gracilis, also commonly known as the greenhouse millipede. Homeowners are starting to go on high alert after finding a few of these species in their homes.
“Centipede invasions have long been a problem for many Alabama residents,” said Xing Ping Hu, an entomologist with Alabama Extension. “These insects usually move after heavy rains and a period of dry, hot weather during the summer and fall. The cause of centipede migration appears to be a combination of too much or too little humidity as well as temperature changes.
Finding one of these segmented arthropods in your home can feel like an alien invasion. Like most insects, many of them can become a nuisance. Hu wants Alabamians to heed the warning that these creatures are becoming increasingly active and are already appearing near and inside homes. Centipedes are not harmful to humans or animals, do not bite, infest food or reproduce indoors.
Centipedes belong to a group of arthropods closely related to insects and spiders. They have two pairs of legs on each body segment except the first three. This feature distinguishes them from six-legged insects, eight-legged spiders, and centipedes, which have a pair of legs on each body segment.
Unlike the large, worm-like centipedes, garden centipedes have flat, brown or black-colored bodies with pale, cream-colored legs. They are smaller than other centipede species, about half to three quarters of an inch or 18 to 23 millimeters in length. Young centipedes are small, white to pale in color and have fewer legs. They develop more segments and legs and become darker as they age.
The nature of centipedes
Native to Asia and not the United States, centipedes are detritivores, meaning they eat all kinds of dead and decaying organic matter. This can include leaf litter, mulch, roots, fruit, rich soil, and even grass thatch in lawns. Sometimes they feed on seeds and live plants when no other food is available and become a pest in greenhouses.
Garden millipedes are nocturnal. During the day, they remain inactive and normally congregate in cool, moist areas. They breed in compost heaps, fallen leaves, rotting logs, under rocks in the ground and flower pots. They often go unnoticed due to their hidden habitats until large numbers appear around and inside homes.
Adults mature and begin mating in July and August. During this period, they can be seen climbing on the exterior walls of houses, on sidewalks and on grass. Adults tend to dig tunnels and lay eggs in the ground. They usually overwinter as adults and may live for one or more years.
Friend or enemy?
Although they look evil, centipedes are a positive member of our ecosystems. They serve as important decomposers that remove decaying materials. They also serve as food for many predators such as reptiles, amphibians, birds, mammals and other insects.
According to Hu, at certain times of the year, centipedes become restless and migrate from their normal living places. They appear in patios, driveways, garages, window wells, crawl spaces and basements.
Migrations are often associated with climatic changes or during humid rainy periods. Following heavy rains, thousands of millipedes will emerge from their normal habitat to breathe and wander in search of drier places to survive. This time is when heavy home invasions happen.
Despite their tough exoskeletons, centipedes are very susceptible to desiccation or severe dehydration. Once they abandon their natural habitats and crawl inside a building or carport, they quickly shrivel up and die. Centipedes will not survive without constant exposure to moisture.
Since centipedes do not live indoors for more than a few days, treatment inside homes and buildings is not necessary. Spraying areas with insecticides does little to reduce their numbers. Even if you can kill the ones there, other centipedes will continue to wander away from their breeding sites.
“A vacuum cleaner or a broom and dustpan are often the quickest and most appropriate method of removing them,” Hu said. “Place the centipedes in a plastic bag, seal the bag, and put the bag in an outdoor trash can.”
If you decide to control a centipede housebreaking, it is important to practice Integrated Pest Management (IPM) plans. These plans can be chemical free while providing a great amount of home defense. Chemical options are available but may not provide complete control. Below are some tips for IPM.
Tip 1: Reduce humidity and breeding sites around structures
Perform routine maintenance to create a dry environment around homes and structures by keeping any water runoff away. This eliminates water buildup from leaking pipes, irrigation, and air conditioning condensation.
Eliminate millipede food sources and habitat by keeping your landscape free of leaf debris and grass clippings.
If a layer of mulch is preferred, make it no thicker than two to four inches.
Dethatch your lawn because centipedes thrive in dense layers of plant material just above the soil surface.
Mow and edge your lawn closely so it can dry out faster and reduce habitat opportunities for centipedes.
Keep garbage cans, water barrels and potted plants away from the foundation of the house.
Do not place flower beds and gardens next to structures, especially near crawl spaces and basements.
Remove stones, logs, firewood and other objects near the foundation of the house.
Keep basements and crawl spaces ventilated by installing a dehumidifier and vents. Homeowners can also install a plastic vapor barrier to cover the crawl space floor.
Tip 2: Prevent access to structures
Seal cracks and crevices in walls and foundations where centipedes and other pests could enter. Block weep holes on brick facings and fill large voids in walls around drain pipes and vents with non-toxic steel wool. Put caulk or foam around the steel wool to hold it in place.
Install weatherstripping or brooms on exterior doors.
Caulk around windows and door frames as well as door sills.
Seal cracks behind baseboards where wet ground can attract centipedes as hiding places.
Tip 3: Chemical control
You must read and follow the label for application. This is the most important tip for chemical applications.
Apply EPA-approved organic products such as diatomaceous earth (DE) powder. Treatments should be applied directly to potential entry points such as cracks, crevices, drain holes, voids, utility and pipe penetrations, vents, doors, windows and visible spaces in walls and foundations. DE is not toxic, but it causes insects to dry out and die by absorbing oils and fats from the cuticle of insect skin. It is especially deadly to crawling insects. It remains effective if dry and undisturbed.
Products containing residual contact insecticides for perimeter applications include gamma-cyhalothrin, dinotefuran, bifenthrin, cyfluthrin or carbaryl. Insecticides should be applied around the perimeter of the house and structure in a band of five to twenty feet around potential entry points. You can also rake thick layers of mulch to allow treatment of exposed soil. Of all formulations, water-resistant powders offer the longest residual activity.
Keep creepy creepers out of your home during wet seasons. Study the areas around the house and understand the habits of centipedes better than before. To learn more about centipedes as well as other insects, please visit the Alabama Extension website at www. aces.edu.