What are the three categories in which insecticides are classified?

What are the three categories in which insecticides are classified?

• A. Stomach poisons, contact poisons, fumigants
• B. Stomach poisons
• C. Contact poisons
• D. Fumigants

Answer: (A)

Insecticides are grouped by how pests are affected or, in practical terms, how the poison reaches them: through ingestion, by contact, or as a gas that fills the space. Stomach poisons need the insect to eat treated material, so the poison acts after it’s ingested in the gut. Contact poisons work when the insect touches the treated surface, absorbing the toxin through its outside and often acting quickly on exposed pests. Fumigants are volatile gases that diffuse through cracks, voids, or porous materials, killing pests by inhalation in enclosed spaces. Together, these three cover the main ways insecticides are used in structures. The other options only name a single category, missing two essential ones.

Insecticides are grouped by how pests are affected or, in practical terms, how the poison reaches them: through ingestion, by contact, or as a gas that fills the space. Stomach poisons need the insect to eat treated material, so the poison acts after it’s ingested in the gut. Contact poisons work when the insect touches the treated surface, absorbing the toxin through its outside and often acting quickly on exposed pests. Fumigants are volatile gases that diffuse through cracks, voids, or porous materials, killing pests by inhalation in enclosed spaces. Together, these three cover the main ways insecticides are used in structures. The other options only name a single category, missing two essential ones.