What is a 'contact kill' vs 'stomach poison' mode of action?

What is a 'contact kill' vs 'stomach poison' mode of action?

• A. They are identical
• B. Stomach poisons kill on contact
• C. Contact kill agents kill pests on contact; stomach poisons require ingestion
• D. Contact kill requires ingestion

Answer: (C)

A key idea is how a pesticide acts: whether it works at the moment the pest touches it or only after the pest eats or drinks it. A contact kill product is effective on contact—when the pest touches the treated surface or area, the toxin acts quickly and can kill without the pest needing to ingest anything. A stomach poison, on the other hand, must be ingested; the toxicant acts in the gut after the pest swallows it, so contact alone won’t produce the lethal effect. That’s why the correct description is that contact kill agents kill pests on contact, while stomach poisons require ingestion. The other statements don’t fit this distinction: they either claim they’re identical, or that stomach poisons kill on contact, or that contact kill requires ingestion. Some products may have multiple modes depending on formulation, but the general definitions follow this difference.

A key idea is how a pesticide acts: whether it works at the moment the pest touches it or only after the pest eats or drinks it. A contact kill product is effective on contact—when the pest touches the treated surface or area, the toxin acts quickly and can kill without the pest needing to ingest anything. A stomach poison, on the other hand, must be ingested; the toxicant acts in the gut after the pest swallows it, so contact alone won’t produce the lethal effect.

That’s why the correct description is that contact kill agents kill pests on contact, while stomach poisons require ingestion. The other statements don’t fit this distinction: they either claim they’re identical, or that stomach poisons kill on contact, or that contact kill requires ingestion. Some products may have multiple modes depending on formulation, but the general definitions follow this difference.