The answer to 'when to treat for fumigation' is that fumigation is typically used as a last resort for severe pest infestations that cannot be effectively treated with other methods. Fumigation involves releasing a toxic gas into a home or building, which kills all pests inside. It is an intensive process that requires the entire structure to be sealed and evacuated for several days.
Fumigation is generally only recommended when other pest control methods have failed, or when dealing with a major infestation of pests like termites, bed bugs, or rodents. It's important to work with a licensed professional pest control company to ensure the fumigation process is done safely and effectively.