Termite Guide for Missouri Homeowners

Missouri Termite Risk

Missouri sits in a moderate-to-heavy subterranean termite pressure zone. The entire state — including St. Louis metro, Franklin County, and Gasconade County — has documented Eastern Subterranean Termite activity. Annual professional inspection is a standard recommendation for any Missouri homeowner with a structure that has wood contact with or proximity to soil.

What to Look For

• Mud tubes on foundation walls. Pencil-width earthen tunnels running up foundation walls or piers are the most reliable early sign of active subterranean termite activity. Check both interior and exterior foundation surfaces, particularly in crawl spaces.
• Winged swarmers near windows in spring. Termite reproductive swarms occur in Missouri from February through May. Swarmers found indoors near windows indicate an established colony nearby or within the structure.
• Hollow-sounding wood. Tap structural wood near the foundation with a screwdriver handle. A hollow sound where solid wood is expected indicates possible termite feeding. Probe suspicious areas.
• Discarded wings near windows or vents. Piles of equal-sized shed wings are a post-swarm sign. Termite wings are all the same size — this distinguishes them from flying ant wings, which are unequal.
• Frass or soil in wood. Unlike drywood termite pellet frass, subterranean termites pack their galleries with soil. Wood that reveals dark, soil-packed tunnels when probed indicates subterranean termite activity.

When to Schedule an Inspection

The optimal window for termite inspection in Missouri is February through April, before swarm season peaks. This timing allows treatment to be completed before the most active reproductive period. However, inspections are valuable any time of year — termites feed continuously and an infestation detected in summer or fall is still an infestation that warrants immediate professional attention.

Treatment Options

Liquid Soil Treatment — The industry standard. A termiticide applied to soil around and beneath the structure creates a treated zone that eliminates termites on contact and is transferred through the colony. Modern non-repellent formulations like Termidor are undetectable by termites, ensuring they carry the treatment into the colony rather than avoiding it.

Bait Systems — Stations installed in the soil perimeter attract and poison termites with a growth regulator that disrupts colony molting cycles. Most effective as ongoing monitoring and prevention rather than for active heavy infestations.

Prevention Basics

Eliminate wood-to-soil contact around the structure. Maintain 6 inches of clearance between soil and siding. Remove wood debris, stumps, and stored firewood from the foundation perimeter. Fix moisture intrusion in crawl spaces. Grade soil to drain away from the foundation.