Triamiphos

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Triamiphos is an organophosphate pesticide and fungicide once used to control powdery mildew on apples and ornamental plants. It was one of the early systemic fungicides, and the US manufacturer stopped selling it in 1998.

What it is and how it works
- It combines a triazole fungicide piece with a phosphoramide group.
- Its toxicity comes from inhibiting the enzyme acetylcholinesterase, which is important for nerve signaling. This can cause symptoms similar to other organophosphate pesticides.

History and use
- Triamiphos was first made in 1960 and early on was widely used because it could move inside plants (systemic action).
- Long-term safety testing didn’t start until 1974, and over time other pesticides replaced it.

Toxicity and health effects
- Acute toxicity depends on how fast acetylcholinesterase is inhibited. If inhibition happens very quickly (about 70%), respiratory failure can occur, which can be fatal without treatment.
- In rat studies, acetylcholinesterase inhibition appeared at about 1 ppm during short-term exposure; in multi-generation studies, effects appeared at 0.5–2.5 ppm. A no-effect level was estimated around 0.1 ppm.
- The active metabolite mainly affects red blood cells, and it doesn’t readily enter the brain, so effects are largely muscarinic and nicotinic rather than central nervous system.
- Antidotes like atropine have been used in animal studies to treat severe poisoning.

Other findings
- Some studies suggested changes in cholesterol and lipid metabolism in rats, but later research did not confirm these results.
- There are no well-established human data for Triamiphos poisoning, but it is thought to have toxic effects similar to other organophosphate pesticides.

Current status
- Triamiphos is generally considered discontinued for use as a pesticide. As with other organophosphates, safety concerns and availability of alternative products have limited its use.