Example Case: A Homestay by the Lam Takhong in Pak Chong, 2026, and Green Mold on Wooden Beds

The following is an illustrative example based on situations that commonly occur after floods. It is not the account of a real person.

Ek runs a small six-room homestay not far from the Lam Takhong in Pak Chong district. Next to it is an organic vegetable plot where he has mixed Trichoderma into compost for years. At the end of September 2026, runoff from Khao Yai pushed the river over its banks and water filled every ground-floor room. Wooden beds, plywood wardrobes, mattresses and curtains sat in muddy water for days.

After the water receded, Ek and his staff hosed out the mud, dragged mattresses outside to dry and shut the rooms while waiting for an electrician. A week later, opening a room again, the musty smell was strong enough to push them back. Headboards and the backs of wardrobes were covered in white rings with bright green centers, and the mattresses were dotted with green and black. One staff member who had carried mattresses without a mask sneezed and coughed all day.

Ek wondered whether the green mold was the same Trichoderma he used in his garden, and whether it could harm guests. He asked WHD on LINE. The advice: whatever species the green mold is, mold in a guest room must be dealt with the same way. Throw away mattresses and curtains moldy inside, remove swollen plywood, wash hard surfaces, dry the rooms, and only then book disinfection spraying before reopening.

The Pak Chong, Nakhon Ratchasima Flood of 2026 (B.E. 2569): Facts from News Reports

According to Matichon and Naewna, between 22 and 28 September 2026 runoff from Khao Yai flowed into the Lam Takhong and flooded Mu Si, Khanong Phra, Pak Chong and Nong Sarai subdistricts of Pak Chong district, Nakhon Ratchasima. More than 1,000 families were affected, water reached 1.7 meters at some points, and the river level at Pak Chong subdistrict rose to 8.35 meters against a bank level of 6.50 meters (sources: Matichon and Naewna).

Nationally, Thailand's Department of Disaster Prevention and Mitigation reported, as of 06:00 on 7 October 2026, that floods had affected 27 provinces plus Bangkok, 123 districts, 984 subdistricts and 1,154,875 households, with more than 3.1 million people affected (source: Government Public Relations Department).

A note for searchers: this article covers Pak Chong district in Nakhon Ratchasima, which is a different place from Pak Chong subdistrict in Lom Sak, Phetchabun.

Runoff from forest and hills carries large amounts of soil, leaves and rotting wood. These are the natural habitat of soil fungi like Trichoderma. When mud stays in rooms, under beds and behind cabinets in a closed-up house, mold grows very quickly, especially on wood and wood-pulp products such as plywood, particleboard and the paper facing of gypsum board.

What Is Trichoderma, and Is It Dangerous?

Trichoderma is a genus of fungi living in soil, plant debris and decaying wood worldwide. It grows very fast; colonies usually start as white fluff and turn bright green or yellow-green as they form spores. In Thailand, farmers widely use certain Trichoderma species as a biological control product to suppress soil-borne plant diseases such as root and stem rot, because Trichoderma competes with the disease-causing fungi for space and food. On mushroom farms, by contrast, it is a pest known as green mold.

Whether Trichoderma is dangerous depends on the setting:

• On the farm: properly produced Trichoderma products are widely used, but users should still wear a mask and gloves when mixing the powder, wash hands afterward and follow the label, because breathing large amounts of spore dust can be irritating.
• Inside a flooded house: green mold on wood, mattresses and walls should not be left alone, whether it is Trichoderma or something else. It means materials are still wet, spores are in the air, and several kinds of mold may be growing together.

Health effects worth knowing:

• Allergy and airway irritation: airborne spores and fragments cause sneezing, congestion and coughing, and can trigger asthma in mold-sensitive people.
• Musty odors and volatile compounds: mold growing on wet materials releases the volatile compounds behind musty smells, which give some people headaches or irritated eyes and throats.
• Infection in people with very weak immunity: some Trichoderma species have been reported to cause opportunistic infections. These are rare and mostly occur in people with severe immune deficiency, transplant recipients or patients on peritoneal dialysis.

For most healthy people, low-level mold exposure does not cause serious illness, but a room with widespread mold after a flood has far more spores in the air than normal and should be handled properly. Do not assume the green mold in your home is a harmless farm product; identifying mold requires laboratory testing.

Why Green Mold Grows in Homes After a Flood, and How It Reaches the Body

Mold does not spread from person to person. It affects health when spores and fragments enter the body through:

1. Breathing: lifting mattresses, tearing out plywood, sweeping or opening long-closed rooms sends clouds of green spores into the air.
2. Skin and wounds: especially cuts on hands and feet from wading and hauling timber.
3. Eyes: dust and spores cause stinging, red, watering eyes.
4. Moldy food: bread, fruit and dry goods that got damp.

Green mold spreads quickly after the Pak Chong flood because many buildings use wooden furniture and plywood, ideal food for cellulose-digesting fungi like Trichoderma. Water up to 1.7 meters deep in places saturated these materials, and rooms shut while waiting for electricians or builders trapped the humidity. The CDC notes that mold can start growing within 24 to 48 hours after materials get wet, so a room closed for a week can be heavily colonized.

Symptoms to Watch for in a House with Green Mold After a Flood

These signs do not prove Trichoderma is the cause, but they are common when mold builds up after flooding and are worth discussing with a doctor:

• Sneezing, a blocked or runny nose and nasal itching, especially in rooms that flooded.
• A cough that will not stop after the water goes down, a sore or scratchy throat.
• Chest tightness, wheezing or asthma flare-ups.
• Stinging, red, watering eyes.
• Headaches or feeling unwell in musty rooms.
• Itchy rashes or inflamed wounds where skin touched moldy materials.
• Fever, cough or unusual tiredness in people with weak immunity, who should see a doctor promptly.

Important: high fever, calf pain after wading, red eyes with fever, yellow skin, severe diarrhea or difficulty breathing need hospital care right away, as they may point to other post-flood illnesses such as leptospirosis. This article is general information, not personal medical advice.

Who Is Most at Risk When Green Mold Appears After the Pak Chong Flood of 2026?

• People with very weak immunity, such as chemotherapy patients, transplant recipients and people on peritoneal dialysis.
• People with asthma, allergies or chronic lung disease.
• Young children and older adults who spend most of the day at home.
• Homestay, resort and shop owners and staff who strip out large numbers of mattresses, curtains and furniture.
• Farmers cleaning flooded sheds, greenhouses and compost heaps.
• Travelers with health conditions staying in rooms that have not been properly restored.

Vulnerable people should stay away during demolition and cleaning and return once rooms are dry and disinfected.

Where Green Mold Hides in Homes and Homestays After the Water Recedes

• Wooden bed frames, headboards and legs that stood in water.
• Plywood and particleboard wardrobes and kitchen cabinets, especially the backs against walls.
• Mattresses, pillows, blankets and curtains holding water inside.
• Gypsum walls and wallpaper, whose paper facing feeds mold.
• Laminate and parquet floors with moisture trapped beneath.
• Cardboard boxes, bookshelves and storerooms.
• Greenhouses, compost sacks and growing media that got wet.
• Air conditioners and filters in closed guest rooms.

If a room smells strongly musty even without visible green mold, check behind furniture and under floors before anyone stays there.

Getting a Pak Chong Homestay or Resort Ready for Guests Again

Pak Chong is a popular getaway, so many affected properties are small hotels, homestays and resorts. For these businesses, mold is not only a health question but also a question of trust. Guests notice a musty smell the moment they open the door, and people with allergies or asthma may react within minutes. A practical approach is to restore rooms in batches: finish demolition, washing and drying in one block, disinfect it, ventilate, and reopen only those rooms while work continues elsewhere. Replace mattresses and soft furnishings rather than reusing flood-soaked ones, clean the air conditioning before the first guest arrives, and keep a simple record of what was removed, washed and treated in each room. That record helps staff answer guest questions honestly and shows that the property took recovery seriously after the 2026 flood.

Why DIY Cleaning Alone Is Not Enough When Green Mold Appears After a Flood

• Scrubbing green mold off plywood leaves the surface looking clean, but swollen plywood carries mold inside and it returns. Most of it must be removed.
• Sun-drying mattresses and reusing them: mattresses soaked in muddy water hold mold and germs deep inside; sunlight only treats the outer surface.
• Bleach alone does not reach mold inside wood. Never mix it with ammonia or acidic cleaners.
• Closing rooms and running the air conditioner spreads spores if the filter is already moldy.
• Perfume or air freshener in guest rooms masks the smell briefly, and allergic guests still react.
• Assuming green mold is a harmless farm product: indoor mold is usually a mix of species and does not belong in living spaces.

What works: discard soaked materials, remove swollen plywood, wash hard surfaces, dry completely, then disinfect thoroughly.

WHO and CDC Advice: Clean First, Then Disinfect

WHO and the CDC agree that after a flood you should remove mud, discard porous items that cannot be dried, wash hard surfaces with water and detergent, dry the building as fast as possible, ideally within 24 to 48 hours, and then disinfect surfaces that touched floodwater. Wear an N95 mask, gloves, goggles and boots throughout. Thailand's Department of Disease Control gives similar hygiene advice, so WHD treats disinfection spraying as the finishing step, never a replacement for cleaning.

WHD Disinfection Spraying After the Pak Chong, Korat Flood of 2026 with CHEMGENE HLD4H

The World Health Disinfection (WHD) disinfection service uses trained technicians who spray and/or apply ULV (Ultra Low Volume) fine mist that reaches surfaces, corners, under beds and behind cabinets evenly. The product is CHEMGENE HLD4H, a medical-grade disinfectant from the United Kingdom containing Benzalkonium Chloride and Didecyldimethylammonium Chloride.

According to the service information, the product is stated to cover many viruses, bacteria and fungi, including COVID-19, RSV, influenza H1N1, H5N1 and hand-foot-mouth virus, with a claimed effectiveness of 99.99% and broad-spectrum action. The service page lists approvals or references from Thailand's Department of Medical Sciences, Mahidol University, NHS England and the EN 14476:2013+A2:2019 standard.

Being transparent about Trichoderma: WHD's pages do not name Trichoderma specifically. Trichoderma belongs to the fungi group the product says it covers, and WHO and CDC advise cleaning and then disinfecting flood-contaminated surfaces. For test data on this specific organism, please ask the WHD team. Spraying does not replace removing plywood, mattresses and materials that mold has penetrated, and disinfectant should not be sprayed onto crop beds or compost where you intend to use a biological product.

According to the company, customers include hospitals, schools, shopping malls, airports, offices, airlines, banks and residential buildings. A current promotion includes a free CHEMGENE spray bottle and WELLGIENIC wet wipes, and a tax invoice is available for homestays, resorts and shops that need accounting records.

WHD is based in Bang Khae, Bangkok 10160, with no branch in Nakhon Ratchasima. Upcountry jobs begin with consultation and assessment by phone or LINE using photos and floor area, then a visit date is arranged. Same-day visits cannot be guaranteed, and pricing is given only after assessment. If guest rooms still smell musty, ask about the complementary residential ozone disinfection service.

WHD's Post-Flood Spraying Process for Homes and Homestays with Green Mold

1. Survey and assessment: water depth, how long rooms stayed closed, furniture types, where green mold or musty smells appear, and how many guest rooms, using photos and video on LINE.
2. Mud removal and washing first: discard mattresses, curtains and swollen plywood, wash hard surfaces with water and detergent, and dry rooms as much as possible.
3. Zoning: by guest room, bathroom, kitchen, lobby and storeroom.
4. Spraying: technicians spray and/or apply ULV mist with CHEMGENE HLD4H over walls, floors, beds, cabinets, doors, handles and corners, with no people, guests, pets or plants in the zone.
5. Waiting and re-entry: according to the service information, wait about 30 minutes before normal use, always following the technicians' on-site timing. Ventilate and rinse food-contact surfaces with clean water.

WHD does not claim zero residue, so wait for the time the technicians give before letting guests back in.

10 Reasons to Book Disinfection Spraying After a Flood When You Find Trichoderma Green Mold

1. Forest runoff brought soil, leaves and rotting wood, rich sources of mold, into buildings.
2. ULV mist reaches under beds, behind cabinets and into wall gaps that cloths miss.
3. CHEMGENE HLD4H is stated to cover viruses, bacteria and fungi.
4. It helps address germs from mud and sewage at the same time.
5. Technicians wear protective equipment, so staff and family avoid mold dust.
6. It is a sensible final step before reopening rooms to guests.
7. It suits homes, homestays, resorts, restaurants and community buildings. See the disinfection service page.
8. The work is systematic, zoned by room, with advice on spots to keep watching.
9. Tax invoices are available for accommodation businesses and shops.
10. Consult first on 065-556-6294 or LINE @whd268 and request test data. See the CHEMGENE HLD4H page.

Before and After Disinfection Spraying

Checklist to Prevent Trichoderma Green Mold After the Korat Flood of 2026

• Wear an N95 mask, goggles, rubber gloves and boots.
• Air out long-closed rooms before working inside.
• Wet moldy areas before removal; never dry-sweep.
• Discard mattresses, pillows, curtains and plywood that are swollen or moldy inside.
• Never mix bleach with ammonia or acidic cleaners.
• Use fans or dehumidifiers once visible mold is gone, and open windows on sunny days.
• Clean or replace air conditioner filters before use.
• Watch behind furniture and under floors for two to three more weeks.
• If you use Trichoderma products on your farm, store them away from living areas and dispose of flood-soaked bags as the label advises.
• Before spraying, put away food, dishes and guest supplies; keep people, guests, pets and plants out; return at the time the technicians give.

Frequently Asked Questions: Trichoderma After Floods and Disinfection Spraying

What is Trichoderma?

A fast-growing soil and wood fungus that turns bright green when it forms spores. Farmers use it to control plant disease, but it also grows on damp wood and materials indoors.

Is Trichoderma harmful to people?

For most people the main issue is allergy and airway irritation. Infections are rare and mostly affect people with very weak immunity. See a doctor for symptoms.

What should I do about green mold in my house after a flood?

Wear an N95 mask and gloves, wet the mold, discard soaked materials, wash hard surfaces, dry completely, then disinfect.

Is the green mold in my house Trichoderma?

Not necessarily. Penicillium and Aspergillus can also look green. Only lab testing can tell, but the cleanup is the same.

Does using Trichoderma in my garden make my house moldy?

Using it on crops as labeled does not; post-flood dampness is the main cause. Still, store the product away from living areas and wash hands after use.

Can I sun-dry a moldy flooded mattress and keep using it?

Not recommended. Mattresses soaked in muddy water hold mold and germs deep inside and should be discarded.

Can a cough that will not stop after a flood be caused by mold?

Possibly, especially if it worsens at home, but there are many causes. See a doctor.

Does disinfection spraying get rid of Trichoderma?

The product is stated to cover fungi as a group, but WHD's pages do not name Trichoderma specifically. Spraying treats washed surfaces; ask WHD for test data.

When can guests return after spraying?

According to the service information, after about 30 minutes, but follow the technicians' on-site timing and ventilate first.

Do you serve Pak Chong and Korat in 2026?

WHD is based in Bang Khae, Bangkok, with no Nakhon Ratchasima branch, but offers consultation and assessment for upcountry jobs at 065-556-6294 and LINE @whd268 before scheduling.

The Water Has Gone Down in Pak Chong. Let WHD Help You Finish the Job.

Discard moldy items, wash and dry, then talk to WHD about disinfection spraying for your home, homestay, resort or shop.

View the Disinfection Service

Call 065-556-6294 · LINE @whd268

References

• Matichon, Pak Chong flood 2026: https://www.matichon.co.th/region/news_5909108
• Naewna, Pak Chong flood 2026: https://www.naewna.com/n/?p=84225
• Government Public Relations Department, DDPM data as of 7 Oct 2026: https://www.prd.go.th/th/content/category/detail/id/33/iid/548715
• World Health Organization: https://www.who.int/news-room/fact-sheets
• CDC Floods: https://www.cdc.gov/floods/
• Department of Disease Control, Thailand: https://ddc.moph.go.th/