Garden millipedes (Oxidus gracilis) are challenging to control around structures and often are the cause of service callbacks. These arthropods are associated with moist, decaying organic matter (landscape beds, leaf litter, etc.) and typically go unnoticed until populations swell. They then “migrate” onto nearby sidewalks, driveways, abutting patio slabs and even up the structural foundation — typically following heavy rain.
Millipede management must start early in the year to prevent population buildup and should first focus on non-chemical strategies. Overturn or remove decomposing landscape mulch, pine straw or similar ground cover, and replace it with new material. Also consider changing irrigation practices or landscape bed drainage patterns.
Chemical control options include granular baits and certain residual sprays. For the latter, use a high-volume approach with a low concentration/dilution rate. Thoroughly soak the habitat (per the label) to achieve acceptable efficacy.