In the past week, the extension office has received several calls from homeowners concerned about insects massing in and around their homes. Most of the sightings have been in the basement area inside homes or around driveways and patios outside.
From the samples homeowners have shown me, these mass infestations are millipedes. Millipedes aren’t insects, they’re more closely related to lobsters and shrimp. They are also known as rain worms or thousand-legged worms. Most millipedes are brown to black in color, and can range from less than 1 inch to more than 2 inches in length. They typically feed on decaying vegetation and are often found in damp areas.
Millipedes are known for mass migrations, usually in the spring during heavy rains. Because of the unseasonably wet weather we are experiencing, millipedes are making their way indoors and to the higher ground of patios and driveways. Luckily, millipedes cause little harm to humans. They are not poisonous, but some species do emit fluids that may cause allergic reactions in certain people. They don’t carry diseases and are not known to damage any food inside the home. However, millipedes will often produce a foul odor or leave a stain when disturbed.
Large numbers of millipedes massing inside your home is an indicator of a large population living normally outside your home. Removing some of their preferred shelter, such as rocks, mulch, leaf litter and thick grass, can help control large buildups of millipedes. Millipedes enter homes through small exterior openings and cracks. Caulking cracks and crevices can help prevent entry points. Proper fitting of windows and doors should also be checked.
If millipedes have already entered your home, it is best to sweep or vacuum them up. Indoor pesticide use against millipedes is often not warranted. If needed, dust insecticides such as Drione or Delta dust can help control millipedes quickly. Both of these products provide a quick knockdown and residual control to help control future infestations.
Dusts may not work well in areas that are consistently moist, such as basements. If moisture is present, use Delta dust for control. It’s deemed the only waterproof insecticidal dust on the market.
If millipedes are a persistent issue, you can use insecticides labeled for outdoor use around the home and driveway such as Talstar PL granules. Sprinkle granules around affected areas in a 24-inch wide band around affected areas. There should be no need to treat the entire lawn. Remember, millipedes are beneficial in consuming decaying plant tissue, so we want to keep them around, just not in our homes.