Subterranean Termites. How to Spot Them and Stop Them

Workers are wingless and light caramel. Soldiers have long, narrow amber heads with no eyes.¹ The insects are small next to drywood and dampwood termites, but mature colonies hold hundreds of thousands.¹

You will see the mud before the insects. Workers build shelter tubes from saliva, soil and bits of wood or drywall.¹ Ohio State says the tubes also contain feces and cellulose.²

Swarmers and tubes are the clues. Pellets and kickout holes point to drywood termites instead. Back to the termite hub for all three types.

A swarm starts it. Winged adults fly, pair up and lose their wings. Most die in flight to predators.¹

A surviving pair digs a chamber in the soil, seals it and lays eggs. After a year the new colony may have only about 75 insects.¹ A queen later lays thousands of eggs in a day.¹

Kings and queens live a decade or more, and Ohio State says up to about 20 years.^1,2 If they die, neotenic reproductives take over egg laying.² That is why one treated spot may not end a colony.

• Shelter tubes on foundations, walls or pillars near soil.²
• Swarms of winged termites and shed wings, often near windows.²
• Hollow tunnels that follow the grain and skip the harder summerwood.¹
• Darkened or blistered wood that a screwdriver pushes through.¹
• Lumps in paint over wood.²

Live termites in the wood mean the colony is active.¹ Heavily damaged wood can look hollow while its surface stays intact.²

The risk is to your house. These termites prefer decayed wood, but they can move into sound wood too.¹ A 2,400 square foot home may sit over several colonies with hundreds of thousands of foragers.¹

They also damage soft items next to infested wood, such as leather and Styrofoam.² The sources we used list no disease threat to people. Handle treatment chemicals by the label and keep pets and kids away from treated soil.³

UC IPM says there are no reliable over-the-counter termite products in California. The best methods are for licensed pros only.¹ Ohio State says the same for Ohio.²

Pros use two main tools. A liquid termiticide goes into the soil around the building by drench or injection. Nonrepellent products like fipronil and imidacloprid work at low doses.¹ Or they use bait stations, placed about every 10 feet in Ohio. Baits can take months or years to finish a colony.^1,2

Fumigation and heat do not work on these termites.¹ You can break shelter tubes to cut access, but that only buys time.¹ Fix the moisture too.²

Fixr lists liquid soil treatment at $4 to $14.50 per linear foot and baiting at $8 to $12 per linear foot. Each bait monitoring station costs about $40.⁵

A one-time inspection runs $150 to $350. The overall typical job is $450 to $2,000.⁵ A home with a long foundation or a crawl space with many piers costs more. Ask if the quote includes a re-treatment warranty.

• Keep structural wood at least 12 inches above the soil.¹
• Keep foundation areas ventilated and dry.¹
• Remove stumps, stored lumber and untreated fence posts that touch the ground.¹
• Use pressure-treated lumber where wood meets the weather.¹
• Keep gutters and grading moving water away from the foundation.³
• Inspect every 3 to 5 years.¹

Ohio swarms come in spring and early summer. Winter swarms are uncommon but can happen near warm areas of a building.²

In California, Reticulitermes swarm in the afternoon in spring or fall on clear days after a soaking rain.¹ They forage year-round, with little activity from November to February and high but erratic activity in summer.¹

The eastern subterranean termite is the Ohio species. The state's risk is rated moderate to heavy.² Only certified professionals should treat it.²

Ohio companies need a commercial applicator license from the Ohio Department of Agriculture. Category 10b covers termite control, and category 12 covers wood-destroying insect inspections. Licenses expire each Sept. 30.⁶

Back to the termite hub for Ohio and California together.

Reticulitermes is the most destructive subterranean termite in California. Heterotermes aureus is the worst in the Sonoran Desert of the southeast. The Formosan subterranean termite is limited to a small area near San Diego.¹

Most lenders require a wood destroying pests and organisms inspection. The Structural Pest Control Board lets you check whether one was filed in the last two years.⁷ Get several inspection reports before you pick a company.⁴