Chemical class Organophosphorus insecticide
Chemical Structure Chemical structure of Trichlorfon
CAS Number 52-68-6
Mode of action 1B – Acetylcholinesterase (AChE) inhibitors
Target pests Parasites, red worms, pin worms, round worms, bots, grubs, army worms and insect pests
Hosts Fish tanks, lawn, a range of fruit and vegetable crops, rice, cattle and horses
Formulations Liquid concentrate, emulsifiable concentrate, oral paste, oral granules, pellets, misc. fish tank medication and soluble concentrate
Home garden use Yes
No of Australian Approvals and Registrations 4 active constituents, 8 products
Poison schedule

Schedule 6

Trichlorfon except metrifonate included in Schedule 4
Australian Health-based guidance values

ADI: 0.002 mg/kg bw per day (1986)

No Australian ARfD established

Key issues

  • If residues are present at the level of MRLs, estimated dietary intakes may exceed the EU ARfD.
  • Australia has established MRLs but there are no CODEX MRLs. Potential trade risk.
  • Close to 50 adverse experience reports have been received by the APVMA. Most of these incidents occurred in horses which included adverse effects to the mouth, and one fatality.
  • With respect to home garden uses, there is potential for high exposure leading to unacceptable health risks.
  • High leaching potential. Highly toxic to fish.

Stakeholder perspective

  • Highly important chemical for pest management in a number of horticulture crops.
  •  With respect to the control of fruit spotting bug in macadamias, trichlorfon is a key chemical in pesticide rotation strategies.
  • Low importance and little use in grain crops.
  • Used widely in the management of fruit fly in WA and Qld.

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