Contact your local county Extension office through our County Office List.

   
Planttalk Colorado™ is sponsored by Colorado State University Extension, Denver Botanic gardens, and the Green Industries of Colorado. For additional information on gardening, see Plant Select® and Extension Publications.

1453 – Horsehair Worms   Arrow divider image - marks separation between nested pages that are listed as breadcrumbs.

Horsehair worms, also known as Gordian worms, are a startling oddity, usually spotted during summer rainy periods. They are a thin worm from four to 14 inches long and range in color from brown to clear yellow or white. They are normally found near ponds, streams, birdbaths, pet water dishes and livestock watering troughs. These creatures writhe slowly contouring their hair-like bodies into intricate knots.horsehair worms

In the spring, horsehair worms develop as parasites in bodies of grasshoppers, crickets, cockroaches and some beetles. When mature, they leave the host to lay eggs. About 3-4 weeks later, the larvae hatch. These larvae must parasitize an invertebrate host to develop. The worms spend the winter in the water.

These roundworms are considered beneficial since they parasitize and kill harmful pests like grasshoppers, crickets, beetles, cockroaches and slugs. They do not infect humans, pets, livestock or attack plants. No control measures are recommended.

Tell us what you think!

Do you have a question? Try Ask an Expert!