An 18-Hole Golf Course Could Not Sell Its Twilight Rounds Because Mosquitoes Attacked From Hole 12 Losing 7 Million Baht a Year
Last updated: 7 Sep 2026 | 6 Views |
A true story from an 18-hole golf course in Pathum Thani, Thailand
An 18-Hole Golf Course Could Not Sell Its Twilight Rounds Because Mosquitoes Attacked From Hole 12 — Losing 7 Million Baht a Year
How a single swarm made an entire time band unsellable, and quietly removed seven million baht a year from the books without ever appearing in a report
An 18-hole course in Pathum Thani could not sell a single full twilight round for two years, even though morning tee times were always full. The cause was not price and not course condition. It was mosquitoes rising from the irrigation canal and holding ponds from four in the afternoon, driving players to quit at hole 12. This is the real arithmetic of what that cost, and how the AIROFOG AT35 thermal fogger brought the evening back.
Thanakorn, 51, has managed an 18-hole course beside the Rangsit canal for nine years. He remembers exactly when the problem sharpened. It was not the year a competing course opened, and not the year the economy softened. It was the year the housing project next door filled its land and left a scatter of standing water behind. From that year on, mosquitoes stopped being an annoyance and started eating revenue.
The number that kept him awake was simple. Morning rounds from six to ten sold out nearly every day. Twilight rounds from three in the afternoon, which should be the most profitable band because working people play after work, sold at only 34 percent of capacity, even after the course had cut twilight pricing twice.
What Thanakorn found after standing at hole 12 for seven consecutive days was that players did not dislike the course. Players could not tolerate the mosquitoes. And one person who cannot tolerate them usually takes a group of four away with him, permanently.
Hole 12 is where the players disappeared
Hole 12 sits against the irrigation canal, with the sprinkler system holding pond behind the green. It is the shadiest corner of the property, the stillest, and the most humid. At midday it is the corner players love because it is cooler than anywhere else. After four in the afternoon it becomes the densest mosquito zone on the course.
Thanakorn decided to count properly. He had a caddie in a light shirt stand still for three minutes beside the hole 12 green at five in the afternoon while he filmed it. Forty-one mosquitoes landed on her arms and legs in three minutes. At the same spot at nine in the morning, the count was three. That was no longer a feeling. It was evidence he could take to the owner.
More importantly, hole 12 sits at the middle of the round. A group teeing off at three thirty reaches it around five fifteen, exactly at peak density. So they quit there, at the point where the walk back to the clubhouse is shortest. The course loses the full green fee it should have earned, the dinner it should have sold, and the next booking it should have taken.
When he pulled two years of booking history, the pattern was brutal. Of players who quit mid round in a twilight slot, only 11 percent booked another twilight round within six months. Of players who finished all 18, 63 percent came back.
What the caddies never told the manager
The 26 caddies carry the heaviest load, because they are on the course every day, several rounds a day, and unlike players they cannot walk off. When Thanakorn finally asked in earnest, he learned that several were wearing two long-sleeved layers in 34 degree heat, and some wrapped cloth around their legs under their trousers.
A caddie the staff call Pi Nuan told him she had dengue two years earlier. Six days in hospital, nearly ten thousand baht of lost income. Since then she declined twilight rounds whenever she could. The result was that the course had barely half as many caddies willing to work evenings as mornings, which capped how many twilight groups it could accept regardless of demand.
None of this appears in the financial statements. The course does not pay the caddies' medical bills directly. It pays in labour that is not there, in an evening tee sheet it cannot fill, and in the cost of replacing people who leave for work that does not carry the risk.
Thanakorn put it plainly. He had run the course for nine years and had only just understood that he was not competing with other courses. He was competing with how a person feels standing in beautiful evening light being bitten badly enough to lose their swing.
The one-line review that cost an entire corporate account
Last March a group of 24 from a large company played a twilight round as a site visit before booking their annual tournament. They played to hole 14 and asked to stop. Two days later a one-line review appeared on the course's page: beautiful course, but too many mosquitoes to finish a round.
That single line collected more than 180 reactions and a dozen comments from people saying the same thing. Thanakorn replied as graciously as he could, but the damage was already done. The company held its tournament elsewhere. The event was worth roughly 380,000 baht.
Worse, two other companies that had made enquiries that same year simply went quiet. He can never prove the review was the reason, but he knows that anyone about to commit several hundred thousand baht reads the reviews first.
A golf course is not a restaurant. A single customer carries very high lifetime value and can stay for years. Losing one corporate account is not one lost sale. It is a recurring revenue line that stops arriving every year thereafter.
The night he decided to change the whole approach
One evening after closing, Thanakorn sat with 24 months of revenue by time slot. He highlighted every twilight round that had sold below half, then added up the gap. The figure was roughly 7,100,000 baht a year, before counting the food and drink that should have followed each round.
He compared that against what the course had spent trying to solve mosquitoes over two years: repellent handed to players, mosquito coils at every tee, eight electric traps around the clubhouse, and a contracted spraying truck once a month. Around 190,000 baht a year, with no measurable improvement at all.
His conclusion that night was precise. He had invested correctly in how people felt, and incorrectly in the mechanism. Repellent protects one body for an hour. Traps work within a few metres of themselves. And a monthly contractor arrives when the course is empty, which is almost never when the mosquitoes are out.
The next morning he started researching thermal foggers the course could own and run on its own schedule rather than a contractor's. That search is what led him to the AIROFOG AT35.
What it actually costs
The lost twilight revenue is the largest number by far
Twilight should be the highest-yield band on a golf course because it is when working people are free. At 34 percent of capacity, the annual gap reached seven million baht — dozens of times the cost of a quality thermal fogger, and more than several whole line items in the course maintenance budget.
The health of caddies and grounds staff
Caddies, mowing crews and irrigation technicians are outside for hours during the exact window when mosquitoes are densest. Dengue, chikungunya and Zika are not distant risks here. One illness means lost income for that person and lost labour capacity for the course for days or weeks.
Reputation damage that is harder to repair than dead turf
A dead patch of fairway can be regrown in six weeks. The sentence too many mosquitoes to finish a round stays online for years and is the first thing a prospect reads. Corporate buyers committing hundreds of thousands read it especially carefully.
Concentration and the quality of the game itself
Golf demands stillness. Being bitten mid-swing produces bad shots, and after enough bad shots what a player carries home is not I played poorly but this course is not enjoyable. That is the feeling that stops them returning.
Why the usual fixes do not work
Repellent and coils handed out to players
They genuinely help, for one body and for a short window. Perspiration during a round strips topical repellent within an hour, and coils are nearly useless outdoors in any breeze. Above all they treat the endpoint. They do not remove a single mosquito from the property.
Electric traps around the clubhouse
They work within a limited radius and attract mosquitoes toward a light source, which can concentrate them nearby rather than reduce them. And the course's problem was never the clubhouse. It was hole 12, nearly a kilometre away.
A contracted spraying truck once a month
The contractor comes on his schedule, not on the mosquitoes'. Usually mid-morning or early afternoon, when mosquitoes are deep inside vegetation and the droplets never reach them. And once a month is far too infrequent against a species that goes from egg to adult in roughly seven to ten days.
Larvicide in the ponds alone
Treating standing water is correct and worth doing, but a golf course is surrounded by water it does not control: puddles on neighbouring land, public drainage channels, containers in the housing estate along the fence. Adult mosquitoes fly in fresh every day and do not respect the boundary line.
Aerosol cans for spot treatment
Fine for a restroom or a small shelter, but an 18-hole property covers hundreds of rai. Covering it would take hundreds of cans per pass. It is neither economical nor fast enough to fit the window before the twilight tee times start.
What the course actually needed was fewer adult mosquitoes across a wide area, before the players arrived
Traced to the root, the problem was not that players failed to protect themselves and not that the course was unclean. It was that a large adult mosquito population sheltered in dense shrubs, under mature tree canopies, along the canal bank and around the holding ponds, then emerged together in the late afternoon. So the task was equally clear: reduce that sheltering adult population before it emerges.
The tool that actually does this at golf course scale is a thermal fogger, because fog does something aerosols and traps cannot. It drifts into dense vegetation, under leaf surfaces and into the crevices where mosquitoes rest, and it stays airborne long enough to actually contact them rather than dropping straight to the ground like coarse droplets.
But the fogger has to belong to the course rather than be hired by the visit, because the required timing is every day before the twilight window, and no contractor will supply that daily at a price that makes sense. Ownership gives the course control over timing, frequency and which spots get emphasis.
And the machine has to be durable enough to run daily for years in humidity, close to water, and in constant contact with chemicals. That is precisely why Thanakorn chose the AIROFOG AT35, with a body built from 100 percent stainless steel.
10 reasons the AIROFOG AT35 thermal fogger solves it
1. Fog reaches the vegetation where mosquitoes actually rest
The whole point of golf course mosquito control is reaching the harbourage, not spraying open air. The AIROFOG AT35 produces a fog light enough to drift into ornamental shrubs, under mature canopies, along canal banks and around holding ponds — the places mosquitoes wait out the day.
2. A 100 percent stainless steel body that survives daily use in a wet environment
A golf course is a punishing environment for equipment: sprinkler humidity, evaporation off the ponds, and corrosive chemicals. Machines with plastic or coated-metal bodies typically degrade within a year or two. The AT35's full stainless construction lasts far longer, which is exactly why its cost per year beats a cheap machine you replace repeatedly.
3. Light enough to carry across all 18 holes
There is no cart path to every corner of a golf course, especially along canal edges and behind greens. The AT35 is a shoulder-carried unit light enough for one person to walk it in, or ride a cart to it, and treat the exact spots that need it — which are usually the spots a truck cannot reach and where the mosquitoes are worst.
4. Runs both water-based and oil-based formulations
Courses need to rotate chemistry to slow resistance, and areas near ponds or greens may call for a gentler formulation. The AT35 accepts both, which keeps your annual chemical plan flexible instead of locking you to one product the way some machines do.
5. Fogging happens when mosquitoes are actually active, not when a contractor is free
Owning the machine means staff fog at three in the afternoon every day, before the twilight window opens — which matches mosquito behaviour precisely. This is the difference that changes outcomes: one correctly timed application beats ten badly timed ones.
6. Covers a large area within a tight time window
There is not much time before twilight tee times. The AT35 delivers enough output that two staff can cover the primary risk zones of an 18-hole property in about ninety minutes, which fits the real gap between the morning field clearing and the evening field arriving.
7. Compliant with Thai government standard equipment specifications
For courses operated by government agencies, state enterprises or the armed forces — of which Thailand has a considerable number — the AT35 meets the official standard equipment schedule, so procurement clears easily and acceptance inspection does not require reinterpreting the specification.
8. Certified to German and British standards
These certifications are not a sticker on a box. They mean the machine has been tested for safety and for consistency of droplet size, which is the single most important variable determining whether fog drifts into vegetation or falls uselessly to the ground.
9. 100 percent quality control before dispatch
Every unit is run-tested before it leaves the warehouse rather than sampled by batch. For a course that needs to fog every day without a gap, confidence that the machine works from day one is worth more than a few thousand baht of discount.
10. A Thai service centre with genuine parts and technicians with over 10 years of experience
This matters most over the long run. Foggers have wear parts that consume themselves with use. Having genuine parts and skilled technicians inside Thailand means the course is not idle for a month waiting on an overseas shipment — and stopping for even two weeks lets the mosquito population return to where it started.
Before the thermal fogger
- Twilight rounds selling at 34 percent of capacity
- Players regularly quitting mid-round between holes 12 and 14
- Caddies declining evening work, capping the tee sheet
- A public review stating the course had too many mosquitoes to finish
- A corporate tournament worth 380,000 baht lost to another course
- 190,000 baht a year spent on repellent, coils and contracted spraying with no improvement
After the thermal fogger
- Twilight rounds at 79 percent of capacity within two months
- Mid-round walk-offs in the twilight band down below 3 percent
- Enough caddies accepting evening work to fill the tee sheet daily
- New reviews three months later describing pleasant, comfortable evening play
- Two corporate tournaments won back the following year
- Food and beverage revenue after twilight rounds up 51 percent
The three-step process
1. Survey and map the property's risk points
Walk all 18 holes with the grounds team and mark every point of standing water, dense shrubbery, canal edge, holding pond, grass clipping pile and still-air corner, then rank them. Most courses discover the genuine risk points number only 12 to 18, not the whole property. Knowing them makes fogging faster and uses far less chemical.
2. Fog on a fixed schedule, before the twilight window every day
Begin around three in the afternoon, after the morning field clears and before evening players arrive. Two staff carry the AT35 on foot or by cart along the mapped route. Fog daily for the first two weeks to break the breeding cycle, then move to alternate days or a seasonal schedule.
3. Measure with numbers, not impressions
Establish three fixed counting points on the course. Have a staff member stand still for three minutes at the same time each week and record the count, alongside round completion rates and twilight revenue. Those two data sets will tell you precisely where to increase or reduce frequency.
From someone who uses one
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Why timing matters more than the amount of chemical
The most common misconception in wide-area mosquito control is that more product produces more result. In practice, timing outweighs volume by a wide margin. Aedes mosquitoes, the dengue vector, feed heavily in two windows: early morning and the hour before dusk. Fogging at midday under strong sun means fogging vegetation where mosquitoes are sheltering deep inside, in heat that disperses the fog before it can work.
On a golf course the most productive window is roughly three to four in the afternoon. The sun has softened, surface temperature is falling, wind is dropping — so fog holds at the height you want it for longer — and mosquitoes are just beginning to move out of shelter, before the twilight field arrives.
Wind is the factor most often ignored. Above roughly 10 kilometres per hour, droplets are carried out of the target zone before contacting anything. Choosing calm periods saves chemical and improves results simultaneously. A course that logs weather alongside its mosquito counts will see the correlation clearly within a month.
Finally, consistency beats intensity. A light application delivered on time every day for the first two weeks outperforms a heavy monthly application by a margin that is not close, because it actually interrupts a reproductive cycle that completes in seven to ten days.
What a course should do alongside fogging
A thermal fogger handles adult mosquitoes very well, but if breeding sites are left untouched, new generations simply replace what you removed. The courses that get the best results always do both: fog the adults, and reduce the standing water they can control.
The overlooked spots on a golf course are consistent: saucers under ornamental planters near the clubhouse, old tyres stored behind the equipment shed, gutters blocked with leaf litter, uncovered wash-down water drums, and drainage channels where flow has slowed. These are small sites that produce enormous numbers.
For large holding ponds that cannot be drained, the usual approach is larvivorous fish such as guppies, a chemical-free method that also fits the environmental image a course wants. Pair it with mowing and thinning the shrubbery around the pond edge to reduce adult resting habitat.
Last is talking to the neighbours. Many courses adjoin vacant land or housing estates. Coordinating with the municipality or the landowner to deal with standing water outside the fence measurably reduces the number of mosquitoes flying in, at essentially no cost beyond the conversation.
Frequently asked questions
Can a thermal fogger be used while players are on the course?
Not in the area being treated. The correct approach is to fog while a zone is temporarily closed — typically between the morning field clearing and the twilight field arriving — and allow roughly 30 to 60 minutes before players enter. In practice this is easy, because most courses already have that gap between bands.
Will fogging damage the turf or the greens?
Not when using an insecticide registered for the purpose at the manufacturer's specified dilution. The cautions are simple: do not hold the nozzle close to a green, and do not exceed the stated concentration. Grounds teams should trial a small area for a week first for peace of mind.
How many machines does an 18-hole course need?
Two is the practical answer for 18 holes, because it lets two staff take nine holes each and finish within about ninety minutes. Very large properties or courses with many risk points may want three. A 9-hole course is usually fine with one.
How often should we fog?
Daily for the first two weeks to break the breeding cycle, then two to three times a week through the rainy season when mosquito pressure peaks, and once or twice a week in the dry season. The number that should drive the decision is your weekly mosquito count, not the calendar.
What does each application cost?
The running costs are fuel and chemical, which for an 18-hole property typically land in the low hundreds of baht per application. Compared with contracted spraying billed at thousands of baht per visit, ownership pays for itself within a few months for any course that needs to fog regularly.
Can ordinary staff operate it?
Yes. The AT35 is designed to be straightforward, and general grounds staff learn it in a single training session. The points to emphasise are personal protective equipment, mixing at the correct ratio, and cleaning the machine after every use — which is the single biggest factor in how long the machine lasts.
If it breaks down, how long is the wait?
AIROFOG maintains a service centre and genuine parts in Thailand, with technicians carrying more than 10 years of experience, so there is no month-long wait on overseas shipments. For a course fogging daily this matters more than the purchase price, because two weeks without fogging returns the population to baseline.
How do government-operated courses procure this?
The AIROFOG AT35 conforms to Thailand's government standard equipment schedule, so the specification and budget line can be written under the standard equipment category without reinterpretation. The World Health Disinfection team has delivered to many government agencies and can help prepare the supporting procurement documents.
Seven million baht a year, against one machine
What Thanakorn's story teaches is not really about mosquitoes. It is about diagnosing the right problem. He cut prices, he improved the course, he increased marketing. None of that was wrong. None of it addressed the thing that was actually making players walk off the property.
When he stopped guessing and started measuring, it took seven days to locate the problem and two months to solve it. What he spent was less than the revenue gap he recovered in the first month alone.
If your course has a twilight band that will not sell, caddies who avoid evening work, or reviews that mention mosquitoes, that is not something to endure any longer. It is a solvable problem with a real tool, and it resolves faster than you would expect.
Talk to the World Health Disinfection team about the right model and number of machines for your property, along with guidance on chemistry and a fogging schedule.
See the machine and pricing — click here
Call 065-556-6294 or add LINE @whd268
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