Millipedes, Sowbugs, Pillbugs and Centipedes

In and Around the Home

Occasionally millipedes, sowbugs, pillbugs and centipedes may be found in moist areas of the home, such as in rotting wood or under piles of moist debris in basements, near patio doors, and in garages. Out-of-doors they are not uncommon and may be seen near foundation walls, under logs, in piles of leaves and in gardens. Occasionally large numbers of millipedes leave the soil and crawl onto and into (if there are openings through which they can enter) houses where they may be an extreme nuisance to home dwellers. In a few instances invasions have been noted after periods of extremely wet weather and persist for a few weeks or until cold weather.

Description

Millipedes, sometimes called "thousand leggers," have elongate segmented worm-like bodies with short antennae and 2 pair of legs per body segment. They crawl slowly across the ground, and when disturbed, roll themselves into a coil. In New York State, those most often seen around the home are brownish in color, rounded in profile and about 1 to 1-1/2 inches in length. A few species which occur in wooded areas, however, mayexceed 4 inches in length. A second more flattened form of millipede is not uncommon.

Sowbugs and pillbugs are oval dark-gray, hard shelled arthropods with 7 pairs of legs. They reach about ½ inch in length. They too are found in moist places under debris or in damp soil where decaying vegetation is the usual food, but like millipedes, they can cause some damage to young plants. Pillbugs can roll up into a tight ball when disturbed, sowbugs do not roll up as tightly.

Centipedes ("hundred-leggers") are elongate, short-legged, flattened arthropods with 15 or more pairs of legs. There is one pair of legs per body segment and the antennae are prominent. When disturbed, centipedes often run for cover. Centipedes can deliver a somewhat painful, venomous bite and should be handled with appropriate care. These arthropods are not likely to infest houses unless conditions are quite moist and prey is abundant.

 

Biology and Life History

Centipedes, sowbugs, pillbugs and millipedes are primarily nocturnal, avoiding light. Millipedes, sowbugs and pillbugs normally live outdoors where they feed on decaying vegetation. Occasionally they will attack the stems and roots of young plants, or they may feed on tubers or vegetables stored in cellars or basements. This, however, most frequently happens in the presence of previous damage.

Millipedes deposit eggs in clusters in the soil throughout the summer. Young hatch from the eggs and undergo a series of molts, during which the number of segments is increased. It often takes more than one year to reach sexual maturity. The females of sowbugs and pillbugs carry the young in a pouch on the underside of her body until the young leave the pouch. They may have 2 or more broods per year. Sowbugs often live to be 2 years old.

Centipedes are predaceous, feeding on insects, spiders and other small animals. They do not cause damage to plants.

Management

In the home millipedes, sowbugs and centipedes may be swept up and disposed of out-of-doors. Correct the conditions that lead to excess moisture indoors repair cracks in foundations and caulk around basement windows and other entryways. Keep ground level entrance areas free of decaying leaves and debris. Out-of-doors removing mulches or piles of leaves or other organic matter from areas adjacent to the foundation can help reduce the number of these arthropods. This removes the cover and allows the areas to dry out some; conditions that millipedes, centipedes, sowbugs and pillbugs do not favor. Trim shrubs or other plantings to promote air circulation near foundations, patios, and other similar places to allow additional drying.

For millipedes and sowbugs outside of the home, if necessary, use Baygon, bifenthrin, cyfluthrin, deltamethrin, permethrin, or resmethrin near foundations, entryways, near basement doors and windows, and other areas where millipedes occur. In very moist years large numbers of millipedes may move near foundations to escape excessive soil moisture, and control may be difficult.

For the occasional invasions of large numbers of millipedes, one may have better success by sweeping them up and disposing of them or moving them a good distance away from the home rather than by repeatedly using insecticides.

 

The House Centipede (Scutigera coleoptrata Linaeus)

The house centipede differs from the above related arthropods in that it is fragile, gray to light brown, long legged and about 1 inch in length. It is the only common house infesting centipede. It is sometimes observed running across floors at great speed.

House centipedes prefer to live in moist areas, but they forage actively at night and may be found in drier areas of the home as well. They are predaceous, feeding on insects, spiders and other small animals. They do not cause damage to plants.

Management Of House Centipede
In the home where house centipedes are present, controlling the insects or spiders that they may be feeding on is a good first step toward reducing their numbers.

 

Prepared by: Carolyn Klass, Senior Extension Associate, Cornell University, and Edgar M. Raffensperger, Department of Entomology, Cornell University, 5/73. 1/91 Revised

Pesticide recommendations obtained from: Part I Guide to Pest Management around the Home - Cultural Methods, Cornell Misc. Bulletin S74I and Part II Guide to Pest Management around the Home - 2003-2004 Pesticide Guidelines, Cornell Misc. Bulletin S74II.

This publication contains pesticide recommendations. Changes in pesticide regulations occur constantly and human errors are still possible. Some materials mentioned may no longer be available, and some uses may no longer be legal.

Recommendations and pesticide use may vary depending on on which state you live in.

Read the label before applying any pesticide.

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