A new invasive species of worms has been spotted in Virginia, posing a threat to the local wildlife and pets. These worms, known as hammerhead worms or broadhead planarians, have distinctive shovel-shaped heads and striped bodies that can grow up to 15 inches long.
They secrete a neurotoxin that can paralyze and dissolve their prey, which include earthworms, snails, and slugs.
How did they get here?
Hammerhead worms are native to Southeast Asia, but they have been introduced to other parts of the world through the horticultural trade. They can hitchhike in the soil of potted plants or in mulch and compost. They can also regenerate from fragments, so cutting them into pieces does not kill them but creates more worms.
According to the US Department of Agriculture’s National Invasive Species Information Center, hammerhead worms were first reported in the US in 1891. Since then, they have spread to at least 30 states, mostly in the eastern and southern regions. They prefer warm and moist habitats, such as gardens, greenhouses, and forests.
Why are they a problem?
Hammerhead worms are voracious predators that can decimate the populations of native earthworms and other soil-dwelling animals. This can have negative impacts on the soil quality and fertility, as well as the food web of the ecosystem. Earthworms play an important role in aerating and enriching the soil, as well as providing food for birds, mammals, and amphibians.
Hammerhead worms can also pose a danger to pets and humans if they come into contact with their toxic mucus. The mucus contains tetrodotoxin, a potent neurotoxin that is also found in pufferfish and blue-ringed octopuses. The toxin can cause numbness, tingling, nausea, vomiting, and in severe cases, paralysis and respiratory failure. However, the toxin does not penetrate the skin easily, so it is unlikely to cause harm unless it is ingested or enters the bloodstream through a wound.
How to deal with them?
If you encounter a hammerhead worm in your yard or garden, do not touch it with your bare hands. Wear gloves or use a tool to pick it up and dispose of it safely. You can either put it in a sealed container with rubbing alcohol or salt water, or expose it to direct sunlight or high temperatures to kill it. Do not cut it into pieces or flush it down the toilet, as this may help it spread further.
You can also prevent hammerhead worms from invading your property by inspecting any plants or soil materials that you bring home from nurseries or garden centers. Look for any signs of worms or fragments on the surface or under the pots. You can also use natural predators, such as chickens or ducks, to control the worm population.
If you find a hammerhead worm that you cannot identify or that looks different from the common species, you can report it to your local extension office or submit a photo to iNaturalist , a citizen science platform that helps document biodiversity.