How Termite Baiting Systems Work (And When They Beat Soil Treatment)

A termite baiting system is the quiet option. No drilling through your marble floor, no hundreds of litres of termiticide pumped under the slab, no chemical smell for a week. Just a ring of plastic stations in the garden that, months later, leaves the colony that was eating your door frames dead.

That sounds like marketing, so this article is about the mechanism. How a termite baiting system actually works, what happens on installation day, why it takes as long as it does, and — the part most sales surveys skip — the specific Bangkok situations where baiting genuinely beats soil treatment, and the ones where it doesn't.

If you want the head-to-head comparison of both methods first, read our soil barrier vs baiting guide. This piece goes deeper on one side of it.

What a termite baiting system actually is

Strip away the brand names and a baiting system is three things:

• Stations. Cylindrical plastic housings sunk into the soil around the building, with slots that let termites in. Some systems also have above-ground stations that fix directly onto an active mud tube or infested timber indoors.
• Attractant. A cellulose matrix — timber interceptors or a textured cellulose material — that foraging termites prefer to the surrounding soil and wood.
• Bait. Once termites are feeding in a station, the technician adds the active bait: cellulose laced with a slow-acting insect growth regulator (IGR). In the Exterra system PestsRova installs, the active ingredient is chlorfluazuron, a chitin synthesis inhibitor.

That last word matters. Chitin is what termites build their exoskeleton from. Every time a worker moults, it needs to lay down a new chitin shell. A chitin synthesis inhibitor doesn't poison the termite outright; it stops the next moult from completing. The termite keeps feeding, keeps walking home, keeps sharing food with nestmates — and then dies at its next moult, as does everyone it fed.

How the bait reaches the queen without ever meeting her

Subterranean termite colonies in Thailand — overwhelmingly Coptotermes gestroi, the Asian subterranean termite — run on trophallaxis: mouth-to-mouth food sharing. Workers are the only caste that eats wood. Soldiers, nymphs, the reproductives and the queen are all fed by workers regurgitating processed cellulose.

That is the whole trick of baiting. You don't need the queen to visit the station. You need the workers to:

1. Find the station while foraging (they tunnel through soil in a wide radius around the nest, continuously, and bump into stations the way they bump into fence posts).
2. Prefer the bait to the house. Good bait matrices are deliberately more palatable than structural timber, and termites recruit nestmates to good food sources by pheromone trail.
3. Carry it home and share it. Because the IGR acts slowly, the workers don't die at the station. They die in the nest, weeks later, after distributing the dose through the colony.

As workers die off, the colony's food supply collapses. Soldiers and the queen starve or succumb to the IGR second-hand. The nest — which you never located and never needed to — stops functioning.

Contrast this with a fast-acting contact poison: kill the termites at the station, and the colony simply marks that spot as bad and reroutes. Slowness is the feature.

Installation day: what actually happens

A baiting install is undramatic, which surprises people who've seen a soil treatment crew at work.

In-ground stations go in around the building perimeter at roughly three-metre intervals, closer near known activity and moisture sources. For a typical Bangkok detached house on a 60–100 square wah plot, that's often a dozen to twenty stations; a townhouse with only front and back soil access may need fewer, plus more reliance on above-ground stations. Each station is sunk flush with the soil or paving, lid on top, and mapped.

Placement is the skill. Termites travel along edges and toward moisture, so stations go:

• beside air-con condensate drip points and outdoor taps
• along the foundation line where soil meets concrete
• near service penetrations (the water main, waste pipes, the electrical conduit entry)
• at the base of any planter bed or raised garden against the wall

Above-ground stations are the fast lane. If you already have an active mud tube climbing a pillar, or termites visible inside a built-in wardrobe, the technician fixes a station directly over the activity. Termites are already there, so feeding starts immediately — often the first place the colony takes bait.

Every PestsRova install ends with a station map and a photo report showing where each one sits and what was found. Keep it — it's the document your next inspection, or your buyer's inspector, will want.

The monitoring rhythm: why baiting is a program, not an event

This is where expectations go wrong. A soil barrier is applied once and starts working that afternoon. A termite baiting system works on the colony's schedule, not yours.

A realistic timeline for an active Coptotermes infestation in Bangkok:

| Phase | Typical timing | What's happening | |---|---|---| | Installation | Day 1 | Stations placed; above-ground stations on visible activity | | First monitoring | Weeks 2–4 | Checking which stations have "hits" (termite feeding on interceptors); bait added where found | | Active baiting | Months 1–3 | Heavy bait consumption; workers recruiting nestmates; bait topped up each visit | | Decline | Months 2–4 | Termites at stations look pale, sluggish, fewer soldiers; consumption drops | | Elimination | Months 3–6 | No activity at any station; indoor activity stopped; timber no longer damp | | Ongoing monitoring | Quarterly, ongoing | Stations kept charged with interceptors to catch any new colony foraging in |

Monthly visits during the active phase, dropping to quarterly once the colony is gone. The quarterly phase isn't padding: Bangkok soil contains multiple colonies, and eliminating the one eating your house doesn't stop its neighbour from finding the same pipe penetration next year. Monitoring turns the stations into a permanent early-warning ring.

Monsoon months change the rhythm slightly. Termite foraging accelerates in warm, wet soil, so station hits come faster from May to October; in the cooler dry months of December and January, activity slows and a colony that's in decline can look "gone" before it is. A good technician won't declare elimination on one quiet visit.

When a termite baiting system beats soil treatment

Here's the decision part. Baiting is the better tool when one or more of these is true:

1. You have an active infestation and want the colony dead, not deflected. Soil treatment with a non-repellent termiticide kills foragers that cross it, but its main job is exclusion. If termites are already inside the structure — behind the wardrobe, in the parquet — a barrier between soil and house can leave a population inside with no obligation to leave. Baiting targets the colony itself.

2. Your floors are expensive and you'd like to keep them. Soil treatment under an existing slab means drilling holes on a 30–50 cm grid through whatever is on top: marble, polished concrete, imported tile. The holes are patched, but you will always know where they are. Baiting needs none of that.

3. You're on a high water table or a khlong-side plot. A lot of Bangkok sits on soft, waterlogged clay, and plots near khlongs or in flood-prone districts see the water table rise into the treated zone every rainy season. Termiticide that gets washed or diluted through the soil protects for less time than the label promises. Bait sits in sealed stations and doesn't care.

4. You're in a townhouse or shophouse row. Your soil barrier stops at your property line. Your neighbour's untreated plot two doors down doesn't. In a row, termites move through shared footings and party walls, and a barrier that only covers one unit is a door with two walls missing. Baiting's colony-kill logic works across boundaries: the colony foraging under the row takes bait from your stations regardless of which unit it entered first.

5. You've got a vegetable garden, a fish pond, or a well. Termiticides are used responsibly at label rates, but some owners simply don't want hundreds of litres of any chemical in soil they grow food in. Baiting puts grams of IGR in sealed stations instead.

When soil treatment still wins

Being honest about the other side:

• New construction. Treating the soil before the slab is poured is the cheapest and most complete protection there is. Nothing beats it. We cover this in detail in our new house termite prevention guide.
• You want protection today, not in four months. A barrier works from the afternoon it's applied. If you're about to close on a sale, or about to move in, immediate exclusion matters more than colony elimination.
• There's no active colony and you just want a moat. Preventive protection for a house with no termites is a barrier's home turf. Baiting can be used preventively, but it's paying for a monitoring program to catch something that may never arrive.
• Soil access all the way around. A detached house on its own plot with soil on every side is what soil treatment was designed for.

And a lot of the time, the right answer is both: bait to kill the active colony, then barrier for long-term exclusion, then annual inspections. Any company that recommends the same method for every property before seeing it is selling a product, not solving a problem.

Baiting vs soil barrier: which suits your property?

| Your situation | Lean toward | Why | |---|---|---| | Active termites inside the structure | Baiting | Colony elimination, not deflection | | New build or major renovation | Soil barrier | Pre-slab treatment is unbeatable | | Townhouse or shophouse row | Baiting | Works across untreated neighbours | | Detached house, soil on all sides, no activity | Soil barrier | Clean perimeter, long re-treatment cycle | | Khlong-side, high water table, floods | Baiting | Stations unaffected by saturated soil | | Expensive finished floors over slab | Baiting | No drill grid | | Need protection before a sale closes this month | Soil barrier | Immediate effect | | Vegetable garden, pond, well | Baiting | Minimal chemical in soil |

What a baiting program costs in Thailand

The market runs two ways. Big-brand franchises tend to sell termite-led annual packages from around ฿8,000 a year, quoted after a sales survey, with baiting wrapped into a contract that renews. Independent operators quote the install and the monitoring separately.

PestsRova does termites differently from everything else we treat. General pest work is one flat price by home size, but termites are the one exception: a licensed termite inspection costs ฿990 (free with any year package), includes moisture and activity readings plus photographed evidence, and ends with a written fixed-price proposal. Full termite programs — whether a soil barrier using BASF Termidor HE or an Exterra baiting installation — typically run ฿5,000–15,000 depending on the structure and method, always quoted in writing after inspection and never over the phone. Annual monitoring is free on packages. The current numbers are on our pricing page, and the products themselves are listed on the products page.

Two things to check on any baiting quote, ours included:

• Is bait replenishment included? Some contracts price the stations and then bill each cartridge of bait separately. Consumption during an active infestation can be significant.
• What happens after elimination? The price should drop to a monitoring tier, not stay at active-treatment rates forever.

A full cost breakdown across methods is in our termite treatment cost guide.

Three things owners get wrong about baiting

"The stations are empty, so it isn't working." Empty stations are normal for months, especially when there's no active infestation nearby. Termites find stations by chance while foraging; a quiet station ring around a house with no termites is the system doing its job.

"I'll just buy stations online and do it myself." You can buy housings. What you can't buy over the counter is the registered IGR bait, and without it the stations are just wood in a tube — useful for detecting termites, useless for killing them. You'd also be guessing at placement, which is the entire skill.

Not sure whether you have termites at all? Our flying termites guide covers what a swarm means, and the warning signs post lists what to check before booking anything.

Getting it done

Baiting is the slow, surgical option: no drilling, minimal chemical, and a dead colony rather than a diverted one — provided someone places the stations well and actually turns up to check them. PestsRova installs the Exterra system across all Bangkok BTS and MRT zones, from Sukhumvit townhouses to detached houses out past On Nut and Bang Na, with pet- and kid-safe products, English-speaking lead technicians, and a photo report after every visit. Book a ฿990 inspection through our termite control page, or message us on LINE (@pestsrova) or WhatsApp, daily 8:00–20:00, and you'll have a written proposal for the right method — not just the one we felt like selling.