Dark-Winged Fungus Gnat Larvae: The Marching "Worms"

A homeowner described hundreds of tiny worms moving in a cohesive group across their patio, breaking up when sprayed. Experts at BugGuide.net identified them as larvae of dark-winged fungus gnats (Bradysia spp.). Usually indoor pests of potted plants, outdoors they mass in lawns with high organic matter or thatch, then migrate en masse.

Management:

• Reduce excessive organic matter/thatch.
• Improve drainage.
• Allow soil surface to dry between waterings.
• Beneficial nematodes (Steinernema feltiae) target larvae.

The phenomenon is temporary and harmless to people and pets.