Chemical class Carbamate insecticide and acaricide
Chemical Structure Chemical structure of Methomyl
CAS Number 16752-77-5
Mode of action 1A – Acetylcholinesterase (AChE) inhibitors
Target pests Insect pests
Hosts Agricultural crops including cereals, cotton, fruit, ginger, legumes, mint, oil seed crops, tobacco, potatoes, vegetables, pastures, and peanuts
Formulations Bait, liquid concentrate, emulsifiable concentrate, soluble concentration and aqueous concentrates
Home garden use Yes
No of Australian Approvals and Registrations 12 active constituents, 27 products
Poison schedule

Schedule 6

Methomyl in fly-baits containing 1 per cent or less of methomyl and not less than 0.002 per cent of denatonium benzoate as a bittering agent.

Schedule 7

Methomyl except when included in Schedule 6.
Australian Health-based guidance values

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

No Australian ARfD established

Key issues

  • Potential mammalian developmental and reproductive effects require evaluation.
  • The use of methomyl is restricted in the United States due to human toxicity concerns.
  • Use on grapes was removed in the EU due to unacceptable worker exposure.
  • No Australian ARfD has been established.  Potential dietary exposure concerns arise when considered against JMPR and EU ARfDs.
  • EFSA assessment indicates methomyl poses high acute risk to insectivorous birds, aquatic organisms, bees and non-target arthropods. It is moderately persistent and highly mobile and hence presents off-target risk from run-off.

Stakeholder perspective

  • Methomyl is considered highly important for pest management in citrus, lettuce, macadamia, nectarine, peach, persimmon and stone fruit.
  • Important in managing Western Flower Thrips and Helicoverpa spp.
  • Important where other control options are less effective for Heliothis control.
  • Its use in cotton production is limited. Cotton growers tend to avoid methomyl, as, relative to other chemicals, it is detrimental to maintaining beneficial insects.  Alternatives are available for pest management in cotton.
  • Used widely in the management of fruit fly and various insect pests across a diverse range of cropping situations in WA.

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