Millipedes

Pest Management Fact Sheet #5029

James F. Dill, Pest Management Specialist
Clay A. Kirby, Insect Diagnostician

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Description & Biology

Millipedes usually go unnoticed in the summer because of their nocturnal habits and tendency to disperse. The common species are found in dark, damp, and cool places. They feed almost entirely on decomposing organic matter, which would seem to make them beneficial to the environment. However, for many people, they can become a nuisance in and around homes.

Maine’s common millipedes (which are diplopods, not insects) are up to 3/16″ thick and up to 1¼” long. The body of a millipede has many segments, with two pairs of legs on each segment.

: Millipede on a potato

Water-saturated soil forces millipedes to the surface in search of drier ground. In the fall, they also search for better over-wintering sites. When one or both of these conditions exist (i.e. during wet, fall weather), it is common for large numbers of millipedes to be found in garages, and to a lesser extent, in basements.

Management

Sanitation is the most important factor in suppressing populations of millipedes. One’s goal needs to be to deprive the creatures of their habitat. As when dealing with slugs, earwigs, sowbugs and the like, never give millipedes a place to hide. Any kind of debris or decomposing organic matter is likely to attract millipedes. Even mulch can become a good habitat. You should also locate gaps in doors and other household entry points, then incorporate barriers such as door sweeps to plug the gaps.

If an unbearable amount of millipedes are getting into the house, application of a residual pesticide may be warranted. Outside, spot treatments around areas where millipedes are gaining entry may help. Materials that can be used in this way (and also as band treatments of synthetic pyrethroids) include: permethrin, bifenthrin, deltamethrin, and cyfluthrin or Sevin (carbaryl). If millipedes are getting in through cracks and crevices in the foundation, these can also be treated.

Once millipedes are in the house (typically the garage and/or the cellar), they usually do not live very long. For this reason, we suggest that you just sweep them up and dispose of them, rather than using a pesticide.

When Using Pesticides

ALWAYS FOLLOW LABEL DIRECTIONS!

Pest Management Unit
Cooperative Extension Diagnostic and Research Laboratory
17 Godfrey Drive, Orono, ME 04473
1.800.287.0279 (in Maine)

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