Extension > Garden > Diagnose a problem > What insect is this? > General/curiosity insects > Insect relatives 1 inch and larger > Horsehair worms

Horsehair worms

Phylum nematomorpha

Kristin Dorman-Johnson, National Park Service

Gary Averbeck, Veterinary Pathobiology, University of Minnesota

Description: Several inches to over 14 inches long. Long, very slender worms. Sometimes found emerging from a large insect, e.g. grasshopper, or other anthropod.

Where/When: Found on the ground or on plants, especially near water sources, such as puddles, swimming pools, and horse troughs.

Significance: Beneficial as a recycler of decaying organic matter. Does not harm people or plants. Can sometimes be a nuisance indoors.

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