Fairfax Master Naturalists
Hammerhead Worm
They’re weird, gross, toxic, invasive and… here.
There seems to be an increase in sightings of hammerhead worms in the area, according to the Virginia Master Naturalists Fairfax Chapter. This is in addition to reports on the Nextdoor online platform, including from one woman whose dog was bitten by a hammerhead worm.
Hammerhead worms are an invasive species originally from Southeast Asia. They may have arrived in America as early as the 1890s. They have spread throughout the United States, but an increase in local sightings this summer has drawn new attention to the weird beings.
They feast on earthworms, snails and slugs, and may stun or kill their prey with toxins similar to those found in pufferfish.
“Cutting them or smashing them may result in regeneration. They also emit a toxin, so grabbing them barehanded or getting parts on you may result in toxic burns,” according to Virginia Master Naturalists.
You can kill them by putting them in a bag and freezing them, by soaking them in a bleach/water mixture, or by covering them in salt. Dead worms should not be composted because eggs can survive and bring new worms.
If you see one, take a photo before you kill it — and email the photo (in Fairfax County) to pestmail@fairfaxcounty.gov. In Fairfax County or the City of Alexandria, residents can also upload a photo to iNaturalist or EDDMaps.org.
