How to Keep Horse Flies Away from the Pool

Where Do Horse Fly Larvae Live?

Horse fly larvae live near water and in damp soil -- a completely different environment from the flying, blood-feeding adults:

Larval Habitats

1. Damp mud along ponds and streams -- The most typical horse fly breeding site. Larvae live in the wet mud above the waterline, preying on small creatures that pass by.
2. Marshes and wetlands -- In waterlogged soil, horse fly larvae burrow into the mud and feed on small aquatic insects and worms.
3. Rice paddies and ditch edges -- The damp soil along irrigation ditches on farms often harbors horse fly larvae.
4. Under rotting plant piles -- The bottom of leaf litter piles and decomposing aquatic vegetation, where it's moist and rich in organic matter.

Larval Appearance and Behavior

• Shape: Spindle-shaped, tapered at both ends, about 15-25 mm long.
• Color: Pale green or yellowish-brown, blending with the mud for camouflage.
• Body: Each segment has ring-like ridges that help them move through mud.
• Mouthparts: Predatory, capable of catching and sucking out small insects and worms.
• Breathing: A breathing tube at the tail end extends above the water surface.

How They Differ from Maggots

• Horse fly larvae are predators that eat other small creatures; house fly larvae (maggots) feed on decaying organic matter.
• Horse fly larvae live in damp soil; maggots live in garbage and feces.
• Horse fly larvae are spindle-shaped with ring-like ridges; maggots are cylindrical and smooth.

How to Reduce Horse Fly Larval Breeding

The key to reducing horse flies around your home is disrupting larval breeding sites:

5. Keep yard drainage clear. Eliminate puddles and persistently wet areas.
6. Regularly clean pond edges to reduce mud and silt buildup.
7. Clear leaf litter, dead weeds, and rotting vegetation from the yard.
8. Trim shrubs that extend to the water's edge so sunlight can reach the ground and keep it dry.