We believe our reader has discovered horsehair worms! Horsehair worms are long, thin worms that resemble threads or pieces of hair, as their name so cleverly suggests. They vary in color from a light yellow/tan to a dark brown/black. Horsehair worms can be found as individuals or in masses of up to 100 worms! They are almost always found in or near water.

While adult horsehair worms are free-living organisms, at immature stages they are parasites. Young horsehair worms develop inside the bodies of arthropods such as crickets, grasshoppers, cockroaches, beetles, and other insects. When the horsehair worm is fully developed, it ejects itself from its host body, killing the host in the process. Horsehair worms need a moist environment to survive, so they wait until their host is in or near a body of water to leave its body. Large masses of horsehair worms are most often found after heavy rains, as our reader has witnessed.

Although horsehair worms are considered parasites when it comes to arthropods, they are not dangerous towards humans, domestic animals, or plants. Therefore, no control measures are needed in order to manage horsehair worms. If our reader wants to get these worms off his patio, he can try washing them off the patio and into the neighboring lawn using a hose, or sweeping them away using a broom! Either way, he should know that horsehair worms are generally considered to be beneficial to the environment and not a pest species!

To wrap up, we believe the dozens of white worms our reader found on his patio are horsehair worms. These worms are often found in large groups after heavy rains! Since they are not dangerous or thought of as pests, our reader doesn’t need to worry about them!