What type of poison acts when pests inhale gas through their spiracles?

Fumigants are specifically designed to act as gaseous pesticides that can be inhaled by pests through their spiracles, which are the openings through which insects breathe. When pests come into contact with these gases, the fumigants penetrate their respiratory system and lead to toxicity. This method of action allows for the extermination of pests even when they are not in direct contact with the poison, as the gaseous state can permeate spaces where pests might be hiding.

In contrast, systemic poisons would be absorbed by the plant and affect the pest when it feeds on the plant, while stomach poisons require the pest to ingest them for them to be effective. Contact poisons work through direct contact with the pest's body but do not specifically target their respiratory system as fumigants do. Understanding how fumigants operate helps pest control professionals effectively choose and apply treatments for various pest infestations.