Millipedes are long, segmented arthropods common in Florida’s humid environment, often becoming a nuisance when they migrate indoors. These creatures are detritivores, feeding primarily on decaying organic matter like leaf litter and mulch, and they are highly dependent on moisture to survive. Millipedes are not harmful to humans or pets since they do not bite or sting. However, some Florida species can release a foul-smelling, irritating fluid as a defensive mechanism. Their presence inside a home is usually accidental, as they cannot breed or live for long in dry indoor environments.
Identifying Florida Millipedes and Understanding Their Triggers
Identifying a millipede is simple, as they are distinct from their predatory cousins, the centipedes. Millipedes have a rounded or cylindrical body shape and possess two pairs of legs on almost every body segment, causing them to move slowly with a wave-like motion. Centipedes, conversely, have flattened bodies and only one pair of legs per segment, allowing them to move much faster. Common Florida species include the Yellow-Banded Millipede and the Florida Ivory Millipede, which are often dark-colored with distinct yellow or red markings.
Millipedes are driven indoors by sudden shifts in moisture levels outside the home. Heavy rainfall saturates the ground, flooding their habitats and forcing them to seek higher, drier ground. Conversely, prolonged dry spells can also trigger an invasion as they desperately search for moisture. The presence of large numbers of millipedes inside a home indicates a significant population thriving just outside the structure.
Millipedes thrive in areas rich with organic debris near the foundation, such as thick layers of mulch, dense thatch, grass clippings, or leaf litter. They often hide under stones, boards, or wood piles during the day, emerging at night to crawl across patios and foundations.
Exclusion and Habitat Modification (Preventing Entry)
Long-term management relies heavily on making the outdoor environment near the home less hospitable and physically blocking entry. This proactive approach focuses on eliminating the moisture and food sources that attract these creatures. A crucial first step is to create a dry, bare barrier zone immediately surrounding the foundation.
Mulch, pine straw, and organic debris should be raked back to create an open space of at least six to twelve inches from the foundation wall. This dry barrier helps expose the soil to sunlight, reducing the moisture millipedes need for survival. Firewood and lumber should be stored off the ground and placed a minimum of 20 feet away from the structure to remove potential hiding spots.
Water management is equally important in Florida’s rainy climate. Ensure that all gutters and downspouts are clean and direct water runoff at least five feet away from the foundation to prevent soil saturation. Adjusting irrigation systems to water the lawn in the morning allows the soil surface to dry out before nightfall when millipedes are most active. For areas where a dry barrier is difficult, replacing organic mulch with inorganic materials like pea gravel or crushed stone can significantly reduce moisture retention.
Physical exclusion involves sealing off all potential entry points, as millipedes can squeeze through surprisingly small gaps. Inspect the foundation and use high-quality caulk to seal any cracks, crevices, or utility line penetrations.
Install tight-fitting door sweeps on all exterior doors, opting for brush or vinyl-fin types that create a robust seal against the threshold. Check that all window screens are intact, and ensure the weather stripping around the frames is fully sealed. For crawl spaces, adding fine-mesh screening to vents allows for proper ventilation while preventing millipedes from entering.
Active Removal and Control Methods
When millipedes have already infiltrated the home, the immediate action is physical removal. Since millipedes cannot survive long indoors due to desiccation, sweeping them up or using a vacuum cleaner is an effective indoor control method. Collected millipedes should be immediately disposed of in a sealed plastic bag in an outdoor garbage container to prevent them from crawling back out.
For persistent invasions requiring chemical intervention, a perimeter treatment with a residual insecticide is the most effective approach. Insecticides containing synthetic pyrethroids, such as bifenthrin, cyfluthrin, or lambda-cyhalothrin, are recommended for their rapid action and long residual effect. These products are applied as a liquid barrier three feet up the foundation wall and three to ten feet out onto the surrounding soil and landscape. Granular formulations, which are watered into the soil, are also effective for treating broader lawn areas where millipedes are abundant.
Insecticidal dusts are useful for targeting specific, hard-to-reach void spaces where millipedes might hide or enter. These dry, moisture-resistant dusts can be puffed into wall voids, behind electrical outlets, and into cracks and crevices around utility lines. The dust adheres to the millipede’s exoskeleton, leading to dehydration and death. Any chemical application should be a supplement to, not a replacement for, the primary exclusion and habitat modification strategies.