Subject: Worm-like pests in potted plant
Location: New York
January 3, 2014 8:28 am
I noticed so many worm-like pests in my potted house plants.
Please can you identify them and let me know if they are harmful to the plants or us?
Signature: Anil Antony
These are not worms, but rather Millipedes in the class Diplopoda, creatures with two pairs of legs on each body segment. Millipedes are generally benign creatures. According to BugGuide: “Most eat decaying plant material, but a few spp. occasionally can be carnivorous. Some may also occasionally eat living plants.” We believe they are Flat-Backed Millipedes in the order Polydesmida. According to BugGuide, they have “18 to 22 body rings” which is what we have counted on the specimens in your photo. BugGuide also notes of the Flat-Backed Millipedes: “The largest millipede order, and the only one that produces cyanide as a defense.” The amount of cyanide that would be released by a single threatened Millipede would not have much of an effect on humans. They were most likely introduced to the potted plant at the nursery. Since these millipedes are in indoor plants, you might want to consider controlling them. We do not provide extermination advice.