Triazole fungicides

Chemical class Triazole fungicides – group includes bitertanol, cyproconazole, difenoconazole, epoxiconazole, fenbuconazole, fluquinconazole, flusilazole, flutriafol, hexaconazole, ipconazole, myclobutanil, penconazole, propiconazole, prothioconazole, tebuconazole, tetraconazole, triadimefon, triadimenol, triticonazole
Chemical Structure Chemical structure of Triazole fungicides
CAS Numbers Bitertanol (55179-31-2), Cyproconazole (94361-06-5), Difenoconazole (119446-68-3), Epoxiconazole (135319-73-2), Fenbuconazole (119611-00-6); Fluquinconazole (136426-54-4), Flusilazole (85509-19-9), Flutriafol (76674-21-0), Hexaconazole (79983-71-4), Ipconazole (125225-28-7), Myclobutanil (88671-89-0), Penconazole (66246-88-6), Propiconazole (60207-90-1), Prothioconazole (178928-70-6), Tebuconazole (107534-96-3), Tetraconazole (112281-77-3), Triadimefon (43121-43-3), Triadimenol (55219-65-3), Triticonazole (131983-72-7)
Mode of action 3 – Demethylation inhibitors
Target pests Control powdery mildews, rusts and leaf-spot
Hosts Range of crops including field crops, orchards, vegetables and turf
Formulations Emulsifiable concentrate, suspension concentrate (flowable concentrate), paint, liquid, water dispersible granules, other liquid applied undiluted, flowable concentrate for seed dressing, suspoemulsion, dust, powder, wettable powder, emulsion (oil in water), microencapsulated
Home garden use No
No of Australian Approvals and Registrations

Bitertanol – 2 active constituents, 1 product

Cyproconazole – 6 active constituents, 5 products

Difenoconazole – 9 active constituents, 20 products

Epoxiconazole – 11 active constituents, 39 products

Fenbuconazole – 3 active constituents, 1 product

Fluquinconazole – 2 active constituents, 6 products

Flusilazole – 1 active constituent, no registered products

Flutriafol – 12 active constituents, 68 products

Hexaconazole – 7 active constituents, 5 products

Ipconazole – 1 active constituent, 2 products

Myclobutanil – 8 active constituents, 38 products

Penconazole – 4 active constituents, 5 products

Propiconazole – 23 active constituents, 86 products

Prothioconazole – 3 active constituents, 4 products

Tebuconazole – 28 active constituents, 107 products

Tetraconazole – 3 active constituents, 2 products

Triadimefon – 7 active constituents, 30 products

Triadimenol – 8 active constituents, 38 products

Triticonazole – 3 active constituents, 12 products

Poison schedule

Bitertanol – No Schedule.

Cyproconazole – Schedule 5

Cyproconazole except in preparations containing 10 per cent or less of cyproconazole.

Difenoconazole – Schedule 5.

Epoxiconazole – Schedule 5.

Fenbuconazole – Schedule 5.

Fluquinconazole – Schedule 6.

Flusilazole – No Schedule.

Flutriafol – Schedule 6

Flutriafol except in fertilisers containing 0.5 per cent or less of flutriafol.

Hexaconazole – Schedule 5

Hexaconazole except in preparations containing 5 per cent or less of hexaconazole.

Ipconazole – Schedule 5

Ipconazole in preparations containing 2 per cent or less of ipconazole.

Schedule 6

Ipconazole except when included in Schedule 5.

Myclobutanil – Schedule 5.

Penconazole – Schedule 5.

Propiconazole – Schedule 5

Propiconazole in preparations containing 20 per cent or less of propiconazole.

Schedule 6

Propiconazole except when included in Schedule 5.

Tebuconazole – Schedule 5.

Tetraconazole – Schedule 5

Tetraconazole in preparations containing 20 per cent or less of tetraconazole.

Schedule 6

Tetraconazole except when included in Schedule 5.

Triadimefon – Schedule 5

Triadimefon in wettable powders containing 25 per cent or less of triadimefon.

Schedule 6

Triadimefon except:

  1. When included in Schedule 5; or
  2. In fertilisers containing 5g/kg or less of triadimefon.

Triadimenol – Schedule 5.

Triticonazole – Schedule 5.

Australian Health-based guidance values

Bitertanol: ADI – 0.01 mg/kg bw per day (1982)

Cyproconazole: ADI – 0.01 mg/kg bw per day (1990)

Difenoconazole: ADI – 0.01 mg/kg bw per day (1990)

Epoxiconazole: ADI – 0.01 mg/kg bw per day (2002)

Fenbuconazole: ADI – 0.006 mg/kg bw per day (2003)

Fluquinconazole: ADI – 0.005 mg/kg bw per day (1997)

Flusilazole: ADI – 0.002 mg/kg bw per day (1987)

Flutriafol: ADI – 0.01 mg/kg bw per day (1991)

Hexaconazole: ADI – 0.005 mg/kg bw per day (1990)

Ipconazole: ADI – 0.015 mg/kg bw per day (2010)

Myclobutanil: ADI – 0.03 mg/kg bw per day (1987)

Penconazole: ADI – 0.007 mg/kg bw per day (1986)

Propiconazole: ADI – 0.04 mg/kg bw per day (1983)

Prothioconazole: ADI – 0.01 mg/kg bw per day (2006)

Tebuconazole: ADI – 0.03 mg/kg bw per day (2010)

Triadimefon: ADI – 0.03 mg/kg bw per day (1987)

Triadimenol: ADI – 0.06 mg/kg bw per day (1988)

Triticonazole: ADI – 0.02 mg/kg bw per day (1997)

 

Bitertanol, cyproconazole, difenoconazole, fluquinconazole, flusilazole, flutriafol, hexaconazole, ipconazole, myclobutanil, penconazole, propiconazole, tebuconazole, triadimefon, triadimenol and triticonazole: No Australian ARfD established

Epoxiconazole: ARfD – 0.2 mg/kg bw (2002)

Fenbuconazole: ARfD – 0.2 mg/kg bw (2003)

Prothioconazole: ARfD – 0.03 mg/kg bw (2008)

Tetraconazole: ARfD – 0.2 mg/kg bw (2002)

Key issues

  • Triazole fungicides share common metabolites, the free triazole compounds 1,2,4-triazole, triazole alanine, and triazole acetic acid. The concern is the risk from cumulative exposure to triazoles fungicides and their metabolites.
  • Based on US EPA and Health Canada assessments, Australian label instructions may be inadequate to protect workers - REIs and PPE need to be reviewed.

Stakeholder perspective

  • Highly important for disease management in a number of crops.
  • Some resistance is reported. Despite this, triazole fungicides are considered effective in a number of crops.
  • Considered an essential chemical in chemical rotation strategies for disease management.
  • It is used by the Department of Agriculture and Water Resources as a residual insecticide for interceptions of invertebrates of biosecurity concern and for disinfestation of aircraft and livestock vessels.

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