What Kind of Infestation Requires Fumigation?

Pest problems come in many forms—from ants in the kitchen to mice in the attic. While many infestations can be handled with traps, sprays, or targeted treatments, some severe cases demand a more aggressive solution: fumigation.

But when exactly does fumigation become necessary? What kind of infestations are serious enough to require this method?


What Is Fumigation?

Fumigation is a pest control method that uses gaseous pesticides (fumigants) to eliminate pests within an enclosed space. The structure is sealed, and the gas penetrates every corner, crack, and crevice, killing pests hidden deep within walls, floors, or furniture.

This is different from surface spraying or baiting, which targets specific areas. Fumigation is a whole-structure solution—ideal for infestations that are widespread or hidden.


Signs You Might Need Fumigation

You may need fumigation if:

  • You've tried other treatments and pests keep returning
  • The infestation is affecting multiple areas of the property
  • The pests are hiding deep inside wood, furniture, or structural components
  • The infestation is causing structural damage
  • You’re preparing to sell or tent a property and need to clear it completely

Fumigation is not always the first line of defense, but in cases of severe or stubborn infestations, it is often the most effective.


Infestations That Typically Require Fumigation

Here are some of the most common pests that require fumigation to be fully eradicated:

1. Termites

Type of fumigation: Structural/tenting

Termites are among the most destructive pests a property can face. They live inside wood, feeding on it 24/7, often undetected until significant damage is done. If you discover:

  • Hollow-sounding wood
  • Mud tubes
  • Discarded wings
  • Frass (termite droppings)

…you could have a termite colony eating away at your walls, floors, or foundation.

Drywood termites, in particular, are often treated with whole-structure fumigation because they nest deep inside wooden structures, where sprays and baits can’t reach.

2. Bed Bugs

Type of fumigation: Container or room-specific

Bed bugs are small, resilient pests that hide in mattresses, furniture, electrical outlets, and even picture frames. They’re notoriously difficult to eliminate with sprays alone.

In cases where:

  • The infestation is large or has spread throughout multiple rooms
  • Repeated treatments have failed
  • Sensitive environments like hotels or dormitories are involved

…fumigation is one of the most thorough solutions. It reaches areas where bed bugs hide and ensures complete extermination in one treatment.

3. Cockroaches (Severe Infestations)

Type of fumigation: Structure-wide or targeted area

Cockroaches are common pests, but mild cases can be controlled with baits and traps. However, in extreme infestations—especially in commercial kitchens, warehouses, or multi-unit buildings—fumigation may be required.

Signs that a roach infestation may need fumigation include:

  • Seeing large numbers during the day
  • Persistent roach sightings after multiple treatments
  • Roaches appearing in multiple parts of the building
  • Strong, oily odor from infestation

Fumigation can eliminate all life stages, including eggs, which many treatments miss.

4. Powderpost Beetles

Type of fumigation: Tenting or spot fumigation

These small wood-boring beetles are often confused with termites. They damage hardwood and can infest furniture, flooring, and beams.

They’re hard to detect and often only noticed once the damage is significant. Because they live inside the wood, surface sprays aren’t enough. Fumigation kills the insects at all life stages, including larvae inside the wood.

5. Stored Product Pests (Warehouse or Food Storage)

Common pests: Grain beetles, weevils, moths

In commercial food production or storage, infestations by insects like flour beetles or Indian meal moths can spread quickly, contaminating large volumes of product.

Fumigation is often the only practical method for treating large amounts of stored food or warehouse goods without discarding everything.

6. Rodents (Limited Use)

Although fumigation is not typically used for rodents, in very specific industrial settings (like ships or grain silos), fumigants may be used to eliminate rats or mice that cannot be reached by traps or poisons.

In most residential or commercial settings, rodent control is handled separately with exclusion, traps, and baiting.


What Fumigation Doesn’t Work For

It’s important to understand that fumigation is not effective or recommended for:

  • Ant infestations (unless combined with other treatments)
  • Wasps, hornets, or bees (dangerous for these protected species)
  • Fleas or ticks (usually handled with sprays)
  • Wildlife like raccoons or squirrels
  • Mold or fungus (requires mold remediation, not fumigation)

Always consult a pest control professional to assess whether fumigation is appropriate.


The Fumigation Process: What to Expect

If fumigation is recommended, here’s a basic overview of what happens:

  1. Inspection – A pest control professional will assess the infestation.
  2. Preparation – You'll be asked to vacate the property and remove pets, food, and plants.
  3. Sealing – The building is sealed or tented to contain the fumigant.
  4. Fumigation – The gas is released and allowed to circulate for a specific period (usually 24–72 hours).
  5. Aeration – The building is ventilated and tested to ensure it’s safe to re-enter.
  6. Re-entry – After clearance, you can return to a pest-free environment.