I have been getting questions about these little worms crawling around outside and inside of people’s homes. Millipedes and centipedes are minor nuisance pests that tend to move into houses during brief periods in the fall or spring. Millipedes may feed on tender seedlings in greenhouses and gardens. Control is rarely necessary. If required, it primarily should involve moisture control because these arthropods are susceptible to drying.
Millipedes and centipedes generally are found in small numbers in damp locations around the yard. Occasionally, they become unusually abundant or move into homes, where they may cause considerable concern to homeowners.
The most common millipedes are dark brown and reach 1 to 1 ½ inches when full grown. They are round and elongated, with many small legs. When dead or disturbed, they tend to curl into a tight coil.
Millipedes do not bite or pose any danger to humans. They feed on rotting organic matter such as leaves and wood and rarely feed on tender green leaves and roots. They spend almost all their time in moist areas, such as under rocks or logs and in lawn thatch.
Movement into houses often is sudden and sporadic. Most millipede movement takes place in September and October and again in mid spring. Invasions often take place shortly after a period of wet weather and end as suddenly as they start.
Because millipedes require high moisture, they usually die in a home within a day or two. Chronic problems are associated with damp conditions. Measures taken to dry out moist areas usually are sufficient. The hard body of the millipede, however, remains intact for a considerable time after it is dead.
Because millipedes cause no damage in homes other than minor annoyance, the best way to handle infestations is to wait a few days for the problem to subside, then vacuum the bodies that remain. Remove debris and other favorite habitats from around building foundations to help reduce problems. Seal or caulk openings around the foundation to reduce future millipede problems.
Where problems are more severe, spray a band on the foundation exterior with an insecticide to prevent movement into homes.
If you have any further questions, please contact Clint Perkins with the Smith County Extension Office, 1517 W. Front St. in Tyler, or call 903-590-2980.