Dithiocarbamates—priority 1

Chemical class Dithiocarbamates—group includes mancozeb, metiram, propineb, thiram, zineb and ziram
Chemical Structure Chemical structure of Dithiocarbamates
CAS Number Mancozeb (8018-01-7), Metiram (9006-42-2), Propineb (12071-83-9), Thiram (137-26-8), Zineb (12122-67-7), Ziram (137-30-4)
Mode of action M3—Multi-site activity
Target pests

Weeds—winter grass and fat hen

Soil-borne pests—nematodes and symphilids

Fungal diseases—rhizoctonia, pythium, phytophthora, sclerotinia and clubroot of crucifers
Hosts Various ornamental, food (fruit, vegetables, rice) and fibre crops, turf
Formulations Wetable powder, water dispersible granules, dry flowable, soluble powder, suspension concentrate (flowable concentrate), granular, dust, dry flowable, suspoemulsion, flowable concentrate for seed dressing, paint and aqueous concentrate 
Home garden use Yes
No of Australian Approvals and Registrations

Mancozeb—14 active constituents, 70 products

Metiram—1 active constituent, 3 products

Propineb—1 active constituent, 2 products

Thiram—6 active constituents, 28 products

Zineb—2 active constituents, 2 products

Ziram—2 active constituents, 4 products
Poison schedule

Mancozeb—Schedule 5.

Metiram—Schedule 5.

Propineb—Schedule 6.

Thiram—Schedule 6

Thiram except in paint containing 0.5 per cent or less of thiram.

Zineb—Schedule 5.

Ziram—Schedule 6

Ziram in granular preparations
Australian Health-based guidance values

Mancozeb: ADI – 0.006 mg/kg bw per day (1992)

Metiram: ADI – 0.02 mg/kg bw per day (1988)

Propineb: ADI – 0.0005 mg/kg bw per day (2007)

Thiram: ADI – 0.004 mg/kg bw per day (1995)

Zineb: ADI – 0.005 mg/kg bw per day (1992)

Ziram: ADI – 0.01 mg/kg bw per day (1995)

Mancozeb, metiram, zineb and ziram – No Australian ARfD established

Propineb: ARfD – 2 mg/kg bw (2010)

Thiram: ARfD – 0.1 mg/kg bw (2010)

Key issues

  • The risk posed by members of this group can be cumulative based on a common mechanism of toxicological action and therefore it is important that the group is looked at as a whole. For example, mancozeb, maneb and metiram are known to cause thyroid toxicity by the formation of a common metabolite - ethylene thiourea (ETU). Because of this common metabolite involved, cumulative risk needs to be considered.
  • Dietary exposure estimates indicate an exceedance of the ADI for some of the dithiocarbamates. It would be beneficial to establish a group ADI to allow refinement of the dietary exposure assessment.
  • Some dithiocarbamates do not have an Australian ARfD. Preliminary calculations using European values indicate acute dietary intake concerns.
  • Some dithiocarbamates are used repeatedly in a crop growing season and therefore workers will be exposed repeatedly. Current labels lack limits on repeated applications or combinations with other dithiocarbamates.
  • There have been multiple residue detections exceeding MRLs.

Stakeholder perspective

  • Dithiocarbamates are highly important for pest management in many horticulture crops.
  • In pulse crops, dithiocarbamates are important for integrated pest management (IPM) and are used in rotation with chlorothalinol and triazoles.
  • Dithiocarbamates are also used for seed treatment in post-entry quarantine situations
  • Access to these chemicals needs to be maintained.

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