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Science-based gardening information for Colorado communities from CSU Extension, Denver Botanic Gardens, and Green Industries of Colorado.

1453 – Horsehair Worms   arrow

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.

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